This book contains the Polkadot Fellowship Requests for Comments (RFCs) detailing proposed changes to the technical implementation of the Polkadot network.
polkadot-fellows/RFCs
(source)
Table of Contents
Polkadot$ / Polkadot Dollar / PDD (exact name TBD) is a new DOT-collateralized stablecoin deployed on Asset Hub. It is an overcollateralized stablecoin backed purely by DOT. The implementation follows the Honzon protocol pioneered by Acala.
Availability (bitfield) votes gain a preferred_fork flag which expresses the validator's opinion upon relay chain equivocations and babe forks, while still sharing availability votes for all relay chain blocks. We make relay chain block production require a supermajority with preferred_fork set, so forks cannot advance if they split the honest validators, which creates an early soft concensus. We similarly defend ELVES from relay chain equivocation attacks and prevent redundent approvals across babe forks.
preferred_fork
-"Polkadot Hub should have a native DOT backed stable coin because people need it and otherwise we will haemorrhage benefits, liquidity and/or security." - Gav -
"Polkadot Hub should have a native DOT backed stable coin because people need it and otherwise we will haemorrhage benefits, liquidity and/or security." - Gav
Primary use cases of PDD:
We've always known relay chain equivocations break the ELVES threat model. We originally envisioned ELVES having fallback pathways, but doing fallbacks requires dangerous subtle debugging. We support more assignment schemes in ELVES this way too, including one novel post-quantum one, and very low CPU usage schemes.
We expect this early soft concensus creates back pressure that improves performance under babe forks.
Alistair: TODO?
We modify the availability votes and restrict relay chain blocks, fork choice, and ELVES start conditions, so mostly the parachain. See alternatives notes on the flag under sassafras chains like JAM.
PDD is implemented using the Honzon protocol stack used to power aUSD, adapted for DOT-only collateral on Asset Hub.
The Honzon protocol functions as a lending system where users can:
The PDD system relies on robust oracle infrastructure to maintain accurate price feeds for DOT and ensure proper collateral valuations.
Oracle source
Price aggregation mechanism
DOT holders can open a vault (CDP) to lock their DOT and borrow up to a protocol-defined percentage of its value as PDD, subject to a required collateral ratio and debt ceilings.
At any time, the vault owner can repay PDD (principal plus accrued interest via the debit exchange rate) to unlock DOT, fully or partially.
When a vault's collateral ratio falls below the liquidation ratio, it becomes unsafe and is liquidated. The system employs a tiered liquidation approach to maximize efficiency and minimize market impact.
Primary liquidation: DEX-first approach
Fallback liquidation: auction mechanism
Liquidation process flow
Any excess collateral after repaying debt and penalties is refunded to the owner. Shortfalls become bad debt and are handled by CDP treasury mechanisms.
A Financial Fellowship (within the broader Polkadot on-chain governance framework) will govern risk parameters and Treasury actions to ensure economic safety. The Fellowship can also perform emergency actions, such as freezing the oracle price feed if manipulation is detected.
As a last resort, an emergency shutdown can be performed by the Fellowship to halt minting/liquidation and allow equitable settlement: lock oracle prices, cancel auctions, and let users settle PDD against collateral at the locked rates.
Testing requirements
Security considerations
At present, availability votes have a bitfield representing the cores, a relay_parent, and a signature. We process these on-chain in several steps: We first validate the signatures, zero any bits for cores included/enacted between the relay_parent and our predecessor, sum the set bits for each core, and finally include/enact the core if this exceeds 2/3rds of the validators.
relay_parent
Availability votes gain a preferred_fork flag, which honest validators set for exactly one relay_parent on their availability votes in a block production slot. We say a validator prefers a fork given by chain head h if it provides an availability vote with relay_parent = h and preferred_fork set.
h
relay_parent = h
Validators recieve a minor equivocations slash if they claim to set preferred_fork for two different relay_parents in the same slot. In sassafras, this means preferred fork equivocations can only occur for relay chain equivocations, but under babe preferred fork equivocations could occur between primary and secondary blocks, or other primary blocks.
All validators still provide availability votes for all forks, because those non-preferred votes could still help enact candidates faster, but those non-preferred vote have preferred_fork zeroed.
Around this, validators could optionally provide an early availability vote that commits to their preferred fork, and then later provide a second availability votes stating the same preferred fork but a fuller bitfield, provided doing so somehow helps relay chain blcok producers.
We require relay chain block producers build upon forks preferred by 2 f + 1 validators. In other words, a relay chain block with parent p must contain availability bitfield votes from 2 f + 1 validators with relay_parent = p and preferred_fork set. It follows our preferred fork votes override other fork choice priorities.
2 f + 1
p
relay_parent = p
A relay chain block producer could lack this 2 f + 1 threshold for a prespective parent block p, in which case they must build upon the parent of p instead. We know availability votes simply being slow would cause this somtimes, in which case adding slightly more delay could save the relay chain slot Alternatively though, two distinct relay chain blocks in the same slot could each wind up prefered by f+1 validators, in which case we must abandond the slot entirely.
f+1
We only launch the approvals process aka (machine) elves for a relay chain block p once 2 f + 1 validators prefer that block, aka 2 f + 1 validators provide availability votes with relay_parent = p and preferred_fork set. We could optionally delay this further until we have some valid decendent of p.
In fact, this new fork choice logic creates more short relay chain forks than exist currently: If the validators split their votes, then we create a new fork in a later slot. We no longer need to process every fork now though.
Instead, availability votes from honest validators must express the correct preferred fork, which requires validators carefully time when they judge and announce their preference flags. In babe, we need primary slots to be preferred over secondary slots, so the validators need logic that delays sending availability votes for a secondary slot, giving the primary slot enough time. We also prefer the primary slot with smallest VRF as well, so we need some delay even once we recieve a primary.
We suggest roughly this approach:
First, download only relay chain block headers, from which we determine our tentative preferred fork.
Second, we download and import only our currently tentatively preferred fork. We download our availability chunks as soon as we import a currently tentatively preferred relay chain block. We've no particular target for availability chunks other than simply some delay timer. In babe, we add some extra delay here for secondary slots, like perhaps 2 seconds minus the actual execution time, so that a fast secondary slot cannot beat a primary slot.
We somtimes obtain an even more preferable header during import, chunk distribution, and delays for our first tentatively preferred fork. Also, the first could simply turn out invalid. In either case, we loop to repeat this second step on our new tentative preferred fork. We repeat this process until an import succeeds and its timers run out, without receiving any more preferable header. Actual equivocations cannot be preferable over one another, so all this loops terminates reasonably quickly.
Next, we broadcast our availability vote with its relay_parent set to our tentatively preferred fork, and with its preferred_fork set.
Finally, if 2 f + 1 other validators have a different preference from us, then we download and import their preferred relay chain block, fetch chunks for it, and provide availability votes with preferred_fork zero. It's possible this occurs earlier than our preference finishes, in which case we probably still send out our preference, if only for forensic evidence.
Adds subtle timing constraints, which could entrench existing performanceg obstacles. We might explore variations that ignore wall clock time.
We've always known relay chain equivocations break the ELVES threat model. We originally envisioned ELVES having fallback pathways, but these were complex and demanded unused code paths, which cannot realistically be debugged. Although complex, the early soft concensus scheme feels less complex overall. We know timing sucks to optimise a distributed system, but at least doing so use everyday code paths.
This proposal introduces necessary computational overhead to Asset Hub for CDP management and liquidation monitoring. The impact is minimized through:
The proposal optimizes for several key usage patterns:
We expect early soft concensus introduce back pressure that radically alters performance. We no longer run approvals checks upon all forks. As primary slots occur once every other slot in expectation, one might expect a 25% reduction in CPU load, but this depends upon diverse factors.
We apply back pressure by dropping some whole relay chain blocks though, so this shall increase the expected parachain blocktime somewhat, but how much depens upon future optimisation work.
Major upgrade
The implementation follows the Honzon protocol pioneered by Acala for their aUSD stablecoin system. Key references include:
...
We halt the chain when less than 2/3 of validators are online. We consider this reasonable since governance now runs on a parachain, ELVES would not secure, and nothing can be finalized anyways. We could perhaps add some "recovery mode" where the relay chain embeds entire system parachain blocks, but doing so might not warrant the effort required.
Future versions of the system will allow smart contracts to register as liquidation participants, enabling:
In a later phase, staking rewards may be paid in PDD instead of DOT inflation, requiring:
Arguably, a sassafras RC like JAM could avoid preferred_fork flag, by only releasing availability votes for at most one sassafras equivocation. We wanted availability for babe forks, but sassafras has only equivocations, so those block can simply be dropped.
In principle, a sassafras equivocation could still enter the valid chain, assuming 2/3rd of validators provide availability votes for the same equivocations. If JAM lacks the preferred_fork flag then enactment proceeds slower in this case, but this should almost never occur.
We think threshold randomness could reduce the tranche zero approcha checker assigments by roughly 40%, meaning a fixed 15 vs the expected 25 in the elves paper (30 in production now).
We do know threshold VRF based schemes that address relay chain equivocations directly, by using as input the relay chain block hash. We have many more options with early soft concensus though. TODO In particular, we only know two post-quantum approaches to elves, and the bandwidth efficent one needs early soft concensus.
In this RFC, we only require that each relay chain block contain preference votes for its parent from 2/3rds of validators. We could enforce the opposite direction too: Around y>2 seconds after a validator V has seen preference votes for a chain head X from 2/3rd of validators, the V begins rejecting any relay chain block that does not build upon X. This is tricky because the y>2 second delay must be long enough so that most honest nodes learn both X and its preference votes. In this, we might treat preferred_fork votes as evidence for finality of the parent of the vote's relay_parent. This strengthens MEV defenses that assume some honest nodes.
We know parachains could baset heir slots upon relay chain slots, instaed of wall clock time (RFC ToDo). After this happens, we could avoid or minimize wall clock timing in the relay chain too, so that relay chain slots could've a floating duration based upon workload.
Above, we only discuss abandoning realy chain blocks which fail early soft concensus. We could alternatively treat them as partial blocks and build extension partial blocks that complete them, with elves probably using randomness from the final partial block.
In future, anytime $w$ seeks chunks in reconstruction $w$ skips $v$ proportional to $\eta_{w,v} / \sum_u \eta_{w,u}$, with each skip reducing $\eta_{w,u}$ by 1. We expect honest accedental availability stiffs have only small $\delta\prime_{w,v}$, so they clear out quickly, but intentional skips add up more quickly.
We keep $\gamma_{w,v}$ and $\alpha_{u,u}$ secret so that approval checkers cannot really know others stiffing perceptions, although $\alpha_{u,v}$ leaks some relevant information. We expect this secrecy keeps skips secret and thus prevents the tit-for-tat escalating beyond one round, which hopefully creates a desirable Nash equilibrium.
We favor skiping systematic chunks to reduce reconstructon costs, so we face costs when skipping them. We could however fetch systematic chunks from availability providers as well as backers, or even other approval checkers, so this might not become problematic in practice.
We do not pay backers individually for availability distribution per se. We could only do so by including this information into the availability bitfields, which complicates on-chain computation. Also, if one of the two backers does not distribute then the availability core should remain occupied longer, meaning the lazy backer loses some rewards too. It's likely future protocol improbvements change this, so we should monitor for lazy backers outside the rewards system.
We discuss approvals being considered by the tit-for-tat in earlier drafts. An adversary who successfuly manipulates the rewards median votes would've alraedy violated polkadot's security assumptions though, which requires a hard fork and correcting the dot allocation. Incorrect report wrong approval_usages remain interesting statistics though.
approval_usages
Adversarial validators could manipulates their availability votes though, even without being a supermajority. If they still download honestly, then this costs them more rewards than they earn. We do not prevent validators from preferentially obtaining their pieces from their friends though. We should analyze, or at least observe, the long-term consequences.
Any rewards protocol could simply be "out voted" by too many slow validators: An increase the number of parachain cores increases more workload, but this creates no-shows if too few validators could handle this workload.
We could add a synthetic parachain flag, only settable by governance, which treats no-shows as positive approval votes for that parachain, but without adding rewards. We should never enable this for real parachains, only for synthetic ones like gluttons. We should not enable the synthetic parachain flag long-term even for gluttonsm, because validators could easily modify their code. Yet, synthetic approval checks might enable pushing the hardware upgrades more agressively over the short-term.
Update the runtime-host interface to no longer make use of a host-side allocator.
The heap allocation of the runtime is currently controlled by the host using a memory allocator on the host side.
The API of many host functions consists in allocating a buffer. For example, when calling ext_hashing_twox_256_version_1, the host allocates a 32 bytes buffer using the host allocator, and returns a pointer to this buffer to the runtime. The runtime later has to call ext_allocator_free_version_1 on this pointer in order to free the buffer.
ext_hashing_twox_256_version_1
ext_allocator_free_version_1
Even though no benchmark has been done, it is pretty obvious that this design is very inefficient. To continue with the example of ext_hashing_twox_256_version_1, it would be more efficient to instead write the output hash to a buffer that was allocated by the runtime on its stack and passed by pointer to the function. Allocating a buffer on the stack in the worst case scenario simply consists in decreasing a number, and in the best case scenario is free. Doing so would save many Wasm memory reads and writes by the allocator, and would save a function call to ext_allocator_free_version_1.
Furthermore, the existence of the host-side allocator has become questionable over time. It is implemented in a very naive way, and for determinism and backwards compatibility reasons it needs to be implemented exactly identically in every client implementation. Runtimes make substantial use of heap memory allocations, and each allocation needs to go twice through the runtime <-> host boundary (once for allocating and once for freeing). Moving the allocator to the runtime side, while it would increase the size of the runtime, would be a good idea. But before the host-side allocator can be deprecated, all the host functions that make use of it need to be updated to not use it.
No attempt was made at convincing stakeholders.
This section contains a list of new host functions to introduce.
(func $ext_storage_read_version_2 + (param $key i64) (param $value_out i64) (param $offset i32) (result i64)) +(func $ext_default_child_storage_read_version_2 + (param $child_storage_key i64) (param $key i64) (param $value_out i64) + (param $offset i32) (result i64)) +
The signature and behaviour of ext_storage_read_version_2 and ext_default_child_storage_read_version_2 is identical to their version 1 counterparts, but the return value has a different meaning. +The new functions directly return the number of bytes that were written in the value_out buffer. If the entry doesn't exist, a value of -1 is returned. Given that the host must never write more bytes than the size of the buffer in value_out, and that the size of this buffer is expressed as a 32 bits number, a 64bits value of -1 is not ambiguous.
ext_storage_read_version_2
ext_default_child_storage_read_version_2
value_out
-1
The runtime execution stops with an error if value_out is outside of the range of the memory of the virtual machine, even if the size of the buffer is 0 or if the amount of data to write would be 0 bytes.
(func $ext_storage_next_key_version_2 + (param $key i64) (param $out i64) (return i32)) +(func $ext_default_child_storage_next_key_version_2 + (param $child_storage_key i64) (param $key i64) (param $out i64) (return i32)) +
The behaviour of these functions is identical to their version 1 counterparts. +Instead of allocating a buffer, writing the next key to it, and returning a pointer to it, the new version of these functions accepts an out parameter containing a pointer-size to the memory location where the host writes the output. The runtime execution stops with an error if out is outside of the range of the memory of the virtual machine, even if the function wouldn't write anything to out. +These functions return the size, in bytes, of the next key, or 0 if there is no next key. If the size of the next key is larger than the buffer in out, the bytes of the key that fit the buffer are written to out and any extra byte that doesn't fit is discarded.
out
0
Some notes:
ext_storage_next_key_version_2
ext_default_child_storage_next_key_version_2
(func $ext_hashing_keccak_256_version_2 + (param $data i64) (param $out i32)) +(func $ext_hashing_keccak_512_version_2 + (param $data i64) (param $out i32)) +(func $ext_hashing_sha2_256_version_2 + (param $data i64) (param $out i32)) +(func $ext_hashing_blake2_128_version_2 + (param $data i64) (param $out i32)) +(func $ext_hashing_blake2_256_version_2 + (param $data i64) (param $out i32)) +(func $ext_hashing_twox_64_version_2 + (param $data i64) (param $out i32)) +(func $ext_hashing_twox_128_version_2 + (param $data i64) (param $out i32)) +(func $ext_hashing_twox_256_version_2 + (param $data i64) (param $out i32)) +(func $ext_trie_blake2_256_root_version_3 + (param $data i64) (param $version i32) (param $out i32)) +(func $ext_trie_blake2_256_ordered_root_version_3 + (param $data i64) (param $version i32) (param $out i32)) +(func $ext_trie_keccak_256_root_version_3 + (param $data i64) (param $version i32) (param $out i32)) +(func $ext_trie_keccak_256_ordered_root_version_3 + (param $data i64) (param $version i32) (param $out i32)) +(func $ext_default_child_storage_root_version_3 + (param $child_storage_key i64) (param $out i32)) +(func $ext_crypto_ed25519_generate_version_2 + (param $key_type_id i32) (param $seed i64) (param $out i32)) +(func $ext_crypto_sr25519_generate_version_2 + (param $key_type_id i32) (param $seed i64) (param $out i32) (return i32)) +(func $ext_crypto_ecdsa_generate_version_2 + (param $key_type_id i32) (param $seed i64) (param $out i32) (return i32)) +
The behaviour of these functions is identical to their version 1 or version 2 counterparts. Instead of allocating a buffer, writing the output to it, and returning a pointer to it, the new version of these functions accepts an out parameter containing the memory location where the host writes the output. The output is always of a size known at compilation time. The runtime execution stops with an error if out is outside of the range of the memory of the virtual machine.
(func $ext_default_child_storage_root_version_3 + (param $child_storage_key i64) (param $out i32)) +(func $ext_storage_root_version_3 + (param $out i32)) +
The behaviour of these functions is identical to their version 1 and version 2 counterparts. Instead of allocating a buffer, writing the output to it, and returning a pointer to it, the new versions of these functions accepts an out parameter containing the memory location where the host writes the output. The output is always of a size known at compilation time. The runtime execution stops with an error if out is outside of the range of the memory of the virtual machine.
I have taken the liberty to take the version 1 of these functions as a base rather than the version 2, as a PPP deprecating the version 2 of these functions has previously been accepted: https://github.com/w3f/PPPs/pull/6.
(func $ext_storage_clear_prefix_version_3 + (param $prefix i64) (param $limit i64) (param $removed_count_out i32) + (return i32)) +(func $ext_default_child_storage_clear_prefix_version_3 + (param $child_storage_key i64) (param $prefix i64) + (param $limit i64) (param $removed_count_out i32) (return i32)) +(func $ext_default_child_storage_kill_version_4 + (param $child_storage_key i64) (param $limit i64) + (param $removed_count_out i32) (return i32)) +
The behaviour of these functions is identical to their version 2 and 3 counterparts. Instead of allocating a buffer, writing the output to it, and returning a pointer to it, the version 3 and 4 of these functions accepts a removed_count_out parameter containing the memory location to a 8 bytes buffer where the host writes the number of keys that were removed in little endian. The runtime execution stops with an error if removed_count_out is outside of the range of the memory of the virtual machine. The functions return 1 to indicate that there are keys remaining, and 0 to indicate that all keys have been removed.
removed_count_out
Note that there is an alternative proposal to add new host functions with the same names: https://github.com/w3f/PPPs/pull/7. This alternative doesn't conflict with this one except for the version number. One proposal or the other will have to use versions 4 and 5 rather than 3 and 4.
(func $ext_crypto_ed25519_sign_version_2 + (param $key_type_id i32) (param $key i32) (param $msg i64) (param $out i32) (return i32)) +(func $ext_crypto_sr25519_sign_version_2 + (param $key_type_id i32) (param $key i32) (param $msg i64) (param $out i32) (return i32)) +func $ext_crypto_ecdsa_sign_version_2 + (param $key_type_id i32) (param $key i32) (param $msg i64) (param $out i32) (return i32)) +(func $ext_crypto_ecdsa_sign_prehashed_version_2 + (param $key_type_id i32) (param $key i32) (param $msg i64) (param $out i32) (return i64)) +
The behaviour of these functions is identical to their version 1 counterparts. The new versions of these functions accept an out parameter containing the memory location where the host writes the signature. The runtime execution stops with an error if out is outside of the range of the memory of the virtual machine, even if the function wouldn't write anything to out. The signatures are always of a size known at compilation time. On success, these functions return 0. If the public key can't be found in the keystore, these functions return 1 and do not write anything to out.
1
Note that the return value is 0 on success and 1 on failure, while the previous version of these functions write 1 on success (as it represents a SCALE-encoded Some) and 0 on failure (as it represents a SCALE-encoded None). Returning 0 on success and non-zero on failure is consistent with common practices in the C programming language and is less surprising than the opposite.
Some
None
(func $ext_crypto_secp256k1_ecdsa_recover_version_3 + (param $sig i32) (param $msg i32) (param $out i32) (return i64)) +(func $ext_crypto_secp256k1_ecdsa_recover_compressed_version_3 + (param $sig i32) (param $msg i32) (param $out i32) (return i64)) +
The behaviour of these functions is identical to their version 2 counterparts. The new versions of these functions accept an out parameter containing the memory location where the host writes the signature. The runtime execution stops with an error if out is outside of the range of the memory of the virtual machine, even if the function wouldn't write anything to out. The signatures are always of a size known at compilation time. On success, these functions return 0. On failure, these functions return a non-zero value and do not write anything to out.
The non-zero value written on failure is:
These values are equal to the values returned on error by the version 2 (see https://spec.polkadot.network/chap-host-api#defn-ecdsa-verify-error), but incremented by 1 in order to reserve 0 for success.
(func $ext_crypto_ed25519_num_public_keys_version_1 + (param $key_type_id i32) (return i32)) +(func $ext_crypto_ed25519_public_key_version_2 + (param $key_type_id i32) (param $key_index i32) (param $out i32)) +(func $ext_crypto_sr25519_num_public_keys_version_1 + (param $key_type_id i32) (return i32)) +(func $ext_crypto_sr25519_public_key_version_2 + (param $key_type_id i32) (param $key_index i32) (param $out i32)) +(func $ext_crypto_ecdsa_num_public_keys_version_1 + (param $key_type_id i32) (return i32)) +(func $ext_crypto_ecdsa_public_key_version_2 + (param $key_type_id i32) (param $key_index i32) (param $out i32)) +
The functions superceded the ext_crypto_ed25519_public_key_version_1, ext_crypto_sr25519_public_key_version_1, and ext_crypto_ecdsa_public_key_version_1 host functions.
ext_crypto_ed25519_public_key_version_1
ext_crypto_sr25519_public_key_version_1
ext_crypto_ecdsa_public_key_version_1
Instead of calling ext_crypto_ed25519_public_key_version_1 in order to obtain the list of all keys at once, the runtime should instead call ext_crypto_ed25519_num_public_keys_version_1 in order to obtain the number of public keys available, then ext_crypto_ed25519_public_key_version_2 repeatedly. +The ext_crypto_ed25519_public_key_version_2 function writes the public key of the given key_index to the memory location designated by out. The key_index must be between 0 (included) and n (excluded), where n is the value returned by ext_crypto_ed25519_num_public_keys_version_1. Execution must trap if n is out of range.
ext_crypto_ed25519_num_public_keys_version_1
ext_crypto_ed25519_public_key_version_2
key_index
n
The same explanations apply for ext_crypto_sr25519_public_key_version_1 and ext_crypto_ecdsa_public_key_version_1.
Host implementers should be aware that the list of public keys (including their ordering) must not change while the runtime is running. This is most likely done by copying the list of all available keys either at the start of the execution or the first time the list is accessed.
(func $ext_offchain_http_request_start_version_2 + (param $method i64) (param $uri i64) (param $meta i64) (result i32)) +
The behaviour of this function is identical to its version 1 counterpart. Instead of allocating a buffer, writing the request identifier in it, and returning a pointer to it, the version 2 of this function simply returns the newly-assigned identifier to the HTTP request. On failure, this function returns -1. An identifier of -1 is invalid and is reserved to indicate failure.
(func $ext_offchain_http_request_write_body_version_2 + (param $method i64) (param $uri i64) (param $meta i64) (result i32)) +(func $ext_offchain_http_response_read_body_version_2 + (param $request_id i32) (param $buffer i64) (param $deadline i64) (result i64)) +
The behaviour of these functions is identical to their version 1 counterpart. Instead of allocating a buffer, writing two bytes in it, and returning a pointer to it, the new version of these functions simply indicates what happened:
ext_offchain_http_request_write_body_version_2
ext_offchain_http_response_read_body_version_2
These values are equal to the values returned on error by the version 1 (see https://spec.polkadot.network/chap-host-api#defn-http-error), but tweaked in order to reserve positive numbers for success.
When it comes to ext_offchain_http_response_read_body_version_2, the host implementers must not read too much data at once in order to not create ambiguity in the returned value. Given that the size of the buffer is always inferior or equal to 4 GiB, this is not a problem.
buffer
(func $ext_offchain_http_response_wait_version_2 + (param $ids i64) (param $deadline i64) (param $out i32)) +
The behaviour of this function is identical to its version 1 counterpart. Instead of allocating a buffer, writing the output to it, and returning a pointer to it, the new version of this function accepts an out parameter containing the memory location where the host writes the output. The runtime execution stops with an error if out is outside of the range of the memory of the virtual machine.
The encoding of the response code is also modified compared to its version 1 counterpart and each response code now encodes to 4 little endian bytes as described below:
The buffer passed to out must always have a size of 4 * n where n is the number of elements in the ids.
4 * n
ids
(func $ext_offchain_http_response_header_name_version_1 + (param $request_id i32) (param $header_index i32) (param $out i64) (result i64)) +(func $ext_offchain_http_response_header_value_version_1 + (param $request_id i32) (param $header_index i32) (param $out i64) (result i64)) +
These functions supercede the ext_offchain_http_response_headers_version_1 host function.
ext_offchain_http_response_headers_version_1
Contrary to ext_offchain_http_response_headers_version_1, only one header indicated by header_index can be read at a time. Instead of calling ext_offchain_http_response_headers_version_1 once, the runtime should call ext_offchain_http_response_header_name_version_1 and ext_offchain_http_response_header_value_version_1 multiple times with an increasing header_index, until a value of -1 is returned.
header_index
ext_offchain_http_response_header_name_version_1
ext_offchain_http_response_header_value_version_1
These functions accept an out parameter containing a pointer-size to the memory location where the header name or value should be written. The runtime execution stops with an error if out is outside of the range of the memory of the virtual machine, even if the function wouldn't write anything to out.
These functions return the size, in bytes, of the header name or header value. If request doesn't exist or is in an invalid state (as documented for ext_offchain_http_response_headers_version_1) or the header_index is out of range, a value of -1 is returned. Given that the host must never write more bytes than the size of the buffer in out, and that the size of this buffer is expressed as a 32 bits number, a 64bits value of -1 is not ambiguous.
If the buffer in out is too small to fit the entire header name of value, only the bytes that fit are written and the rest are discarded.
(func $ext_offchain_submit_transaction_version_2 + (param $data i64) (return i32)) +(func $ext_offchain_http_request_add_header_version_2 + (param $request_id i32) (param $name i64) (param $value i64) (result i32)) +
Instead of allocating a buffer, writing 1 or 0 in it, and returning a pointer to it, the version 2 of these functions return 0 or 1, where 0 indicates success and 1 indicates failure. The runtime must interpret any non-0 value as failure, but the client must always return 1 in case of failure.
(func $ext_offchain_local_storage_read_version_1 + (param $kind i32) (param $key i64) (param $value_out i64) (param $offset i32) (result i64)) +
This function supercedes the ext_offchain_local_storage_get_version_1 host function, and uses an API and logic similar to ext_storage_read_version_2.
ext_offchain_local_storage_get_version_1
It reads the offchain local storage key indicated by kind and key starting at the byte indicated by offset, and writes the value to the pointer-size indicated by value_out.
kind
key
offset
The function returns the number of bytes that were written in the value_out buffer. If the entry doesn't exist, a value of -1 is returned. Given that the host must never write more bytes than the size of the buffer in value_out, and that the size of this buffer is expressed as a 32 bits number, a 64bits value of -1 is not ambiguous.
(func $ext_offchain_network_peer_id_version_1 + (param $out i64)) +
This function writes the PeerId of the local node to the memory location indicated by out. A PeerId is always 38 bytes long. +The runtime execution stops with an error if out is outside of the range of the memory of the virtual machine.
PeerId
(func $ext_input_size_version_1 + (return i64)) +(func $ext_input_read_version_1 + (param $offset i64) (param $out i64)) +
When a runtime function is called, the host uses the allocator to allocate memory within the runtime where to write some input data. These two new host functions provide an alternative way to access the input that doesn't make use of the allocator.
The ext_input_size_version_1 host function returns the size in bytes of the input data.
ext_input_size_version_1
The ext_input_read_version_1 host function copies some data from the input data to the memory of the runtime. The offset parameter indicates the offset within the input data where to start copying, and must be inferior or equal to the value returned by ext_input_size_version_1. The out parameter is a pointer-size containing the buffer where to write to. +The runtime execution stops with an error if offset is strictly superior to the size of the input data, or if out is outside of the range of the memory of the virtual machine, even if the amount of data to copy would be 0 bytes.
ext_input_read_version_1
In addition to the new host functions, this RFC proposes two changes to the runtime-host interface:
(func (result i64))
__heap_base
All the host functions that are being superceded by new host functions are now considered deprecated and should no longer be used. +The following other host functions are similarly also considered deprecated:
ext_storage_get_version_1
ext_default_child_storage_get_version_1
ext_allocator_malloc_version_1
ext_offchain_network_state_version_1
This RFC might be difficult to implement in Substrate due to the internal code design. It is not clear to the author of this RFC how difficult it would be.
The API of these new functions was heavily inspired by API used by the C programming language.
The changes in this RFC would need to be benchmarked. This involves implementing the RFC and measuring the speed difference.
It is expected that most host functions are faster or equal speed to their deprecated counterparts, with the following exceptions:
ext_input_size_version_1/ext_input_read_version_1 is inherently slower than obtaining a buffer with the entire data due to the two extra function calls and the extra copying. However, given that this only happens once per runtime call, the cost is expected to be negligible.
The ext_crypto_*_public_keys, ext_offchain_network_state, and ext_offchain_http_* host functions are likely slightly slower than their deprecated counterparts, but given that they are used only in offchain workers this is acceptable.
ext_crypto_*_public_keys
ext_offchain_network_state
ext_offchain_http_*
It is unclear how replacing ext_storage_get with ext_storage_read and ext_default_child_storage_get with ext_default_child_storage_read will impact performances.
ext_storage_get
ext_storage_read
ext_default_child_storage_get
ext_default_child_storage_read
It is unclear how the changes to ext_storage_next_key and ext_default_child_storage_next_key will impact performances.
ext_storage_next_key
ext_default_child_storage_next_key
After this RFC, we can remove from the source code of the host the allocator altogether in a future version, by removing support for all the deprecated host functions. +This would remove the possibility to synchronize older blocks, which is probably controversial and requires a some preparations that are out of scope of this RFC.
This RFC proposes a dynamic pricing model for the sale of Bulk Coretime on the Polkadot UC. The proposed model updates the regular price of cores for each sale period, by taking into account the number of cores sold in the previous sale, as well as a limit of cores and a target number of cores sold. It ensures a minimum price and limits price growth to a maximum price increase factor, while also giving govenance control over the steepness of the price change curve. It allows governance to address challenges arising from changing market conditions and should offer predictable and controlled price adjustments.
Accompanying visualizations are provided at [1].
RFC-1 proposes periodic Bulk Coretime Sales as a mechanism to sell continouos regions of blockspace (suggested to be 4 weeks in length). A number of Blockspace Regions (compare RFC-1 & RFC-3) are provided for sale to the Broker-Chain each period and shall be sold in a way that provides value-capture for the Polkadot network. The exact pricing mechanism is out of scope for RFC-1 and shall be provided by this RFC.
A dynamic pricing model is needed. A limited number of Regions are offered for sale each period. The model needs to find the price for a period based on supply and demand of the previous period.
The model shall give Coretime consumers predictability about upcoming price developments and confidence that Polkadot governance can adapt the pricing model to changing market conditions.
The primary stakeholders of this RFC are:
The dynamic pricing model sets the new price based on supply and demand in the previous period. The model is a function of the number of Regions sold, piecewise-defined by two power functions.
The curve of the function forms a plateau around the target and then falls off to the left and rises up to the right. The shape of the plateau can be controlled via a scale factor for the left side and right side of the function respectively.
From here on, we will also refer to Regions sold as 'cores' to stay congruent with RFC-1.
BULK_LIMIT
0 < BULK_LIMIT
BULK_TARGET
0 < BULK_TARGET <= BULK_LIMIT
MIN_PRICE
0 < MIN_PRICE
MAX_PRICE_INCREASE_FACTOR
1 < MAX_PRICE_INCREASE_FACTOR
SCALE_DOWN
0 < SCALE_DOWN
SCALE_UP
0 < SCALE_UP
P(n) = \begin{cases} + (P_{\text{old}} - P_{\text{min}}) \left(1 - \left(\frac{T - n}{T}\right)^d\right) + P_{\text{min}} & \text{if } n \leq T \\ + ((F - 1) \cdot P_{\text{old}} \cdot \left(\frac{n - T}{L - T}\right)^u) + P_{\text{old}} & \text{if } n > T +\end{cases} +
old_price
cores_sold
The left side is a power function that describes an increasing concave downward curvature that approaches old_price. We realize this by using the form $y = a(1 - x^d)$, usually used as a downward sloping curve, but in our case flipped horizontally by letting the argument $x = \frac{T-n}{T}$ decrease with $n$, doubly inversing the curve.
This approach is chosen over a decaying exponential because it let's us a better control the shape of the plateau, especially allowing us to get a straight line by setting SCALE_DOWN to $1$.
The right side is a power function of the form $y = a(x^u)$.
NEW_PRICE := IF CORES_SOLD <= BULK_TARGET THEN + (OLD_PRICE - MIN_PRICE) * (1 - ((BULK_TARGET - CORES_SOLD)^SCALE_DOWN / BULK_TARGET^SCALE_DOWN)) + MIN_PRICE +ELSE + ((MAX_PRICE_INCREASE_FACTOR - 1) * OLD_PRICE * ((CORES_SOLD - BULK_TARGET)^SCALE_UP / (BULK_LIMIT - BULK_TARGET)^SCALE_UP)) + OLD_PRICE +END IF +
We introduce MIN_PRICE to control the minimum price.
The left side of the function shall be allowed to come close to 0 if cores sold approaches 0. The rationale is that if there are actually 0 cores sold, the previous sale price was too high and the price needs to adapt quickly.
If the number of cores is close to BULK_TARGET, less extreme price changes might be sensible. This ensures that a drop in sold cores or an increase doesn’t lead to immediate price changes, but rather slowly adapts. Only if more extreme changes in the number of sold cores occur, does the price slope increase.
We introduce SCALE_DOWN and SCALE_UP to control for the steepness of the left and the right side of the function respectively.
We introduce MAX_PRICE_INCREASE_FACTOR as the factor that controls how much the price may increase from one period to another.
Introducing this variable gives governance an additional control lever and avoids the necessity for a future runtime upgrade.
This example proposes the baseline parameters. If not mentioned otherwise, other examples use these values.
The minimum price of a core is 1 DOT, the price can double every 4 weeks. Price change around BULK_TARGET is dampened slightly.
BULK_TARGET = 30 +BULK_LIMIT = 45 +MIN_PRICE = 1 +MAX_PRICE_INCREASE_FACTOR = 2 +SCALE_DOWN = 2 +SCALE_UP = 2 +OLD_PRICE = 1000 +
We might want to have a more aggressive price growth, allowing the price to triple every 4 weeks and have a linear increase in price on the right side.
BULK_TARGET = 30 +BULK_LIMIT = 45 +MIN_PRICE = 1 +MAX_PRICE_INCREASE_FACTOR = 3 +SCALE_DOWN = 2 +SCALE_UP = 1 +OLD_PRICE = 1000 +
If governance considers the risk that a sudden surge in DOT price might price chains out from bulk coretime markets, it can ensure the model quickly reacts to a quick drop in demand, by setting 0 < SCALE_DOWN < 1 and setting the max price increase factor more conservatively.
BULK_TARGET = 30 +BULK_LIMIT = 45 +MIN_PRICE = 1 +MAX_PRICE_INCREASE_FACTOR = 1.5 +SCALE_DOWN = 0.5 +SCALE_UP = 2 +OLD_PRICE = 1000 +
By setting the scaling factors to 1 and potentially adapting the max price increase, we can achieve a linear function
BULK_TARGET = 30 +BULK_LIMIT = 45 +MIN_PRICE = 1 +MAX_PRICE_INCREASE_FACTOR = 1.5 +SCALE_DOWN = 1 +SCALE_UP = 1 +OLD_PRICE = 1000 +
None at present.
This pricing model is based on the requirements from the basic linear solution proposed in RFC-1, which is a simple dynamic pricing model and only used as proof. The present model adds additional considerations to make the model more adaptable under real conditions.
This RFC, if accepted, shall be implemented in conjunction with RFC-1.
This RFC proposes changes that enable the use of absolute locations in AccountId derivations, which allows protocols built using XCM to have static account derivations in any runtime, regardless of its position in the family hierarchy.
These changes would allow protocol builders to leverage absolute locations to maintain the exact same derived account address across all networks in the ecosystem, thus enhancing user experience.
One such protocol, that is the original motivation for this proposal, is InvArch's Saturn Multisig, which gives users a unifying multisig and DAO experience across all XCM connected chains.
This proposal aims to make it possible to derive accounts for absolute locations, enabling protocols that require the ability to maintain the same derived account in any runtime. This is done by deriving accounts from the hash of described absolute locations, which are static across different destinations.
The same location can be represented in relative form and absolute form like so:
#![allow(unused)] +fn main() { +// Relative location (from own perspective) +{ + parents: 0, + interior: Here +} + +// Relative location (from perspective of parent) +{ + parents: 0, + interior: [Parachain(1000)] +} + +// Relative location (from perspective of sibling) +{ + parents: 1, + interior: [Parachain(1000)] +} + +// Absolute location +[GlobalConsensus(Kusama), Parachain(1000)] +}
Using DescribeFamily, the above relative locations would be described like so:
DescribeFamily
#![allow(unused)] +fn main() { +// Relative location (from own perspective) +// Not possible. + +// Relative location (from perspective of parent) +(b"ChildChain", Compact::<u32>::from(*index)).encode() + +// Relative location (from perspective of sibling) +(b"SiblingChain", Compact::<u32>::from(*index)).encode() + +}
The proposed description for absolute location would follow the same pattern, like so:
#![allow(unused)] +fn main() { +( + b"GlobalConsensus", + network_id, + b"Parachain", + Compact::<u32>::from(para_id), + tail +).encode() +}
This proposal requires the modification of two XCM types defined in the xcm-builder crate: The WithComputedOrigin barrier and the DescribeFamily MultiLocation descriptor.
xcm-builder
WithComputedOrigin
The WtihComputedOrigin barrier serves as a wrapper around other barriers, consuming origin modification instructions and applying them to the message origin before passing to the inner barriers. One of the origin modifying instructions is UniversalOrigin, which serves the purpose of signaling that the origin should be a Universal Origin that represents the location as an absolute path prefixed by the GlobalConsensus junction.
WtihComputedOrigin
UniversalOrigin
GlobalConsensus
In it's current state the barrier transforms locations with the UniversalOrigin instruction into relative locations, so the proposed changes aim to make it return absolute locations instead.
The DescribeFamily location descriptor is part of the HashedDescription MultiLocation hashing system and exists to describe locations in an easy format for encoding and hashing, so that an AccountId can be derived from this MultiLocation.
HashedDescription
This implementation contains a match statement that does not match against absolute locations, so changes to it involve matching against absolute locations and providing appropriate descriptions for hashing.
No drawbacks have been identified with this proposal.
Tests can be done using simple unit tests, as this is not a change to XCM itself but rather to types defined in xcm-builder.
Security considerations should be taken with the implementation to make sure no unwanted behavior is introduced.
This proposal does not introduce any privacy considerations.
Depending on the final implementation, this proposal should not introduce much overhead to performance.
The ergonomics of this proposal depend on the final implementation details.
Backwards compatibility should remain unchanged, although that depend on the final implementation.
DescirbeFamily
Implementation details and overall code is still up to discussion.
This RFC proposes to make modifications to voting power delegations as part of the Conviction Voting pallet. The changes being proposed include:
It has become clear since the launch of OpenGov that there are a few common tropes which pop up time and time again:
We believe (based on feedback from token holders with a larger stake in the network) that if there were some changes made to delegation mechanics, these larger stake holders would be more likely to delegate their voting power to active network participants – thus greatly increasing the support turnout.
This RFC proposes to make 4 changes to the convictionVoting pallet logic in order to improve the user experience of those delegating their voting power to another account.
Allow a Delegator to vote independently of their Delegate if they so desire – this would empower network participants to more actively delegate their voting power to active voters, removing the tedious steps of having to undelegate across an entire track every time they do not agree with their delegate's voting direction for a particular referendum.
Allow nested delegations – for example Charlie delegates to Bob who delegates to Alice – when Alice votes then both Bob and Charlie vote alongside Alice (in the current runtime Charlie will not vote when Alice votes) – This would allow network participants who control multiple (possibly derived) accounts to be able to delegate all of their voting power to a single account under their control, which would in turn delegate to a more active voting participant. Then if the delegator wishes to vote independently of their delegate they can control all of their voting power from a single account, which again removes the pain point of having to issue multiple undelegate extrinsics in the event that they disagree with their delegate.
Have delegated votes follow their delegates abstain votes – there are times where delegates may vote abstain on a particular referendum and adding this functionality will increase the support of a particular referendum. It has a secondary benefit of meaning that Validators who are delegating their voting power do not lose points in the 1KV program in the event that their delegate votes abstain (another pain point which may be preventing those network participants from delegating).
Allow a Delegator to delegate/ undelegate their votes for all tracks with a single call - in order to delegate votes across all tracks, a user must batch 15 calls - resulting in high costs for delegation. A single call for delegate_all/ undelegate_all would reduce the complexity and therefore costs of delegations considerably for prospective Delegators.
delegate_all
undelegate_all
We do not foresee any drawbacks by implementing these changes. If anything we believe that this should help to increase overall voter turnout (via the means of delegation) which we see as a net positive.
We feel that the Polkadot Technical Fellowship would be the most competent collective to identify the testing requirements for the ideas presented in this RFC.
This change may add extra chain storage requirements on Polkadot, especially with respect to nested delegations.
The change to add nested delegations may affect governance interfaces such as Nova Wallet who will have to apply changes to their indexers to support nested delegations. It may also affect the Polkadot Delegation Dashboard as well as Polkassembly & SubSquare.
We want to highlight the importance for ecosystem builders to create a mechanism for indexers and wallets to be able to understand that changes have occurred such as increasing the pallet version, etc.
N/A
Additionally we would like to re-open the conversation about the potential for there to be free delegations. This was discussed by Dr Gavin Wood at Sub0 2022 and we feel like this would go a great way towards increasing the amount of network participants that are delegating: https://youtu.be/hSoSA6laK3Q?t=526
Overall, we strongly feel that delegations are a great way to increase voter turnout, and the ideas presented in this RFC would hopefully help in that aspect.
This RFC proposes a new model for a sustainable on-demand parachain registration, involving a smaller initial deposit and periodic rent payments. The new model considers that on-demand chains may be unregistered and later re-registered. The proposed solution also ensures a quick startup for on-demand chains on Polkadot in such cases.
With the support of on-demand parachains on Polkadot, there is a need to explore a new, more cost-effective model for registering validation code. In the current model, the parachain manager is responsible for reserving a unique ParaId and covering the cost of storing the validation code of the parachain. These costs can escalate, particularly if the validation code is large. We need a better, sustainable model for registering on-demand parachains on Polkadot to help smaller teams deploy more easily.
ParaId
This RFC suggests a new payment model to create a more financially viable approach to on-demand parachain registration. In this model, a lower initial deposit is required, followed by recurring payments upon parachain registration.
This new model will coexist with the existing one-time deposit payment model, offering teams seeking to deploy on-demand parachains on Polkadot a more cost-effective alternative.
This RFC proposes a set of changes that will enable the new rent based approach to registering and storing validation code on-chain. +The new model, compared to the current one, will require periodic rent payments. The parachain won't be pruned automatically if the rent is not paid, but by permitting anyone to prune the parachain and rewarding the caller, there will be an incentive for the removal of the validation code.
On-demand parachains should still be able to utilize the current one-time payment model. However, given the size of the deposit required, it's highly likely that most on-demand parachains will opt for the new rent-based model.
Importantly, this solution doesn't require any storage migrations in the current system nor does it introduce any breaking changes. The following provides a detailed description of this solution.
In the current implementation of the registrar pallet, there are two constants that specify the necessary deposit for parachains to register and store their validation code:
#![allow(unused)] +fn main() { +trait Config { + // -- snip -- + + /// The deposit required for reserving a `ParaId`. + #[pallet::constant] + type ParaDeposit: Get<BalanceOf<Self>>; + + /// The deposit to be paid per byte stored on chain. + #[pallet::constant] + type DataDepositPerByte: Get<BalanceOf<Self>>; +} +}
This RFC proposes the addition of three new constants that will determine the payment amount and the frequency of the recurring rent payment:
#![allow(unused)] +fn main() { +trait Config { + // -- snip -- + + /// Defines how frequently the rent needs to be paid. + /// + /// The duration is set in sessions instead of block numbers. + #[pallet::constant] + type RentDuration: Get<SessionIndex>; + + /// The initial deposit amount for registering validation code. + /// + /// This is defined as a proportion of the deposit that would be required in the regular + /// model. + #[pallet::constant] + type RentalDepositProportion: Get<Perbill>; + + /// The recurring rental cost defined as a proportion of the initial rental registration deposit. + #[pallet::constant] + type RentalRecurringProportion: Get<Perbill>; +} +}
Users will be able to reserve a ParaId and register their validation code for a proportion of the regular deposit required. However, they must also make additional rent payments at intervals of T::RentDuration.
T::RentDuration
For registering using the new rental system we will have to make modifications to the paras-registrar pallet. We should expose two new extrinsics for this:
paras-registrar
#![allow(unused)] +fn main() { +mod pallet { + // -- snip -- + + pub fn register_rental( + origin: OriginFor<T>, + id: ParaId, + genesis_head: HeadData, + validation_code: ValidationCode, + ) -> DispatchResult { /* ... */ } + + pub fn pay_rent(origin: OriginFor<T>, id: ParaId) -> DispatchResult { + /* ... */ + } +} +}
A call to register_rental will require the reservation of only a percentage of the deposit that would otherwise be required to register the validation code when using the regular model. +As described later in the Quick para re-registering section below, we will also store the code hash of each parachain to enable faster re-registration after a parachain has been pruned. For this reason the total initial deposit amount is increased to account for that.
register_rental
#![allow(unused)] +fn main() { +// The logic for calculating the initial deposit for parachain registered with the +// new rent-based model: + +let validation_code_deposit = per_byte_fee.saturating_mul((validation_code.0.len() as u32).into()); + +let head_deposit = per_byte_fee.saturating_mul((genesis_head.0.len() as u32).into()) +let hash_deposit = per_byte_fee.saturating_mul(HASH_SIZE); + +let deposit = T::RentalDepositProportion::get().mul_ceil(validation_code_deposit) + .saturating_add(T::ParaDeposit::get()) + .saturating_add(head_deposit) + .saturating_add(hash_deposit) +}
Once the ParaId is reserved and the validation code is registered the rent must be periodically paid to ensure the on-demand parachain doesn't get removed from the state. The pay_rent extrinsic should be callable by anyone, removing the need for the parachain to depend on the parachain manager for rent payments.
pay_rent
If the rent is not paid, anyone has the option to prune the on-demand parachain and claim a portion of the initial deposit reserved for storing the validation code. This type of 'light' pruning only removes the validation code, while the head data and validation code hash are retained. The validation code hash is stored to allow anyone to register it again as well as to enable quicker re-registration by skipping the pre-checking process.
The moment the rent is no longer paid, the parachain won't be able to purchase on-demand access, meaning no new blocks are allowed. This stage is called the "hibernation" stage, during which all the parachain-related data is still stored on-chain, but new blocks are not permitted. The reason for this is to ensure that the validation code is available in case it is needed in the dispute or approval checking subsystems. Waiting for one entire session will be enough to ensure it is safe to deregister the parachain.
This means that anyone can prune the parachain only once the "hibernation" stage is over, which lasts for an entire session after the moment that the rent is not paid.
The pruning described here is a light form of pruning, since it only removes the validation code. As with all parachains, the parachain or para manager can use the deregister extrinsic to remove all associated state.
deregister
The paras pallet will be loosely coupled with the para-registrar pallet. This approach enables all the pallets tightly coupled with the paras pallet to have access to the rent status information.
paras
para-registrar
Once the validation code is stored without having its rent paid the assigner_on_demand pallet will ensure that an order for that parachain cannot be placed. This is easily achievable given that the assigner_on_demand pallet is tightly coupled with the paras pallet.
assigner_on_demand
If the rent isn't paid on time, and the parachain gets pruned, the new model should provide a quick way to re-register the same validation code under the same ParaId. This can be achieved by skipping the pre-checking process, as the validation code hash will be stored on-chain, allowing us to easily verify that the uploaded code remains unchanged.
#![allow(unused)] +fn main() { +/// Stores the validation code hash for parachains that successfully completed the +/// pre-checking process. +/// +/// This is stored to enable faster on-demand para re-registration in case its pvf has been earlier +/// registered and checked. +/// +/// NOTE: During a runtime upgrade where the pre-checking rules change this storage map should be +/// cleared appropriately. +#[pallet::storage] +pub(super) type CheckedCodeHash<T: Config> = + StorageMap<_, Twox64Concat, ParaId, ValidationCodeHash>; +}
To enable parachain re-registration, we should introduce a new extrinsic in the paras-registrar pallet that allows this. The logic of this extrinsic will be same as regular registration, with the distinction that it can be called by anyone, and the required deposit will be smaller since it only has to cover for the storage of the validation code.
This RFC does not alter the process of reserving a ParaId, and therefore, it does not propose reducing it, even though such a reduction could be beneficial.
Even though this RFC doesn't delve into the specifics of the configuration values for parachain registration but rather focuses on the mechanism, configuring it carelessly could lead to potential problems.
Since the validation code hash and head data are not removed when the parachain is pruned but only when the deregister extrinsic is called, the T::DataDepositPerByte must be set to a higher value to create a strong enough incentive for removing it from the state.
T::DataDepositPerByte
The implementation of this RFC will be tested on Rococo first.
Proper research should be conducted on setting the configuration values of the new system since these values can have great impact on the network.
An audit is required to ensure the implementation's correctness.
The proposal introduces no new privacy concerns.
This RFC should not introduce any performance impact.
This RFC does not affect the current parachains, nor the parachains that intend to use the one-time payment model for parachain registration.
This RFC does not break compatibility.
Prior discussion on this topic: https://github.com/paritytech/polkadot-sdk/issues/1796
None at this time.
As noted in this GitHub issue, we want to raise the per-byte cost of on-chain data storage. However, a substantial increase in this cost would make it highly impractical for on-demand parachains to register on Polkadot. +This RFC offers an alternative solution for on-demand parachains, ensuring that the per-byte cost increase doesn't overly burden the registration process.
Rather than enforce a limit to the total memory consumption on the client side by loading the value at :heappages, enforce that limit on the runtime side.
:heappages
From the early days of Substrate up until recently, the runtime was present in two forms: the wasm runtime (wasm bytecode passed through an interpreter) and the native runtime (native code directly run by the client).
Since the wasm runtime has a lower amount of available memory (4 GiB maximum) compared to the native runtime, and in order to ensure sure that the wasm and native runtimes always produce the same outcome, it was necessary to clamp the amount of memory available to both runtimes to the same value.
In order to achieve this, a special storage key (a "well-known" key) :heappages was introduced and represents the number of "wasm pages" (one page equals 64kiB) of memory that are available to the memory allocator of the runtimes. If this storage key is absent, it defaults to 2048, which is 128 MiB.
The native runtime has since then been disappeared, but the concept of "heap pages" still exists. This RFC proposes a simplification to the design of Polkadot by removing the concept of "heap pages" as is currently known, and proposes alternative ways to achieve the goal of limiting the amount of memory available.
Client implementers and low-level runtime developers.
This RFC proposes the following changes to the client:
With these changes, the memory available to the runtime is now only bounded by the available memory space (4 GiB), and optionally by the maximum amount of memory specified in the Wasm binary (see https://webassembly.github.io/spec/core/bikeshed/#memories%E2%91%A0). In Rust, the latter can be controlled during compilation with the flag -Clink-arg=--max-memory=....
-Clink-arg=--max-memory=...
Since the client-side change is strictly more tolerant than before, we can perform the change immediately after the runtime has been updated, and without having to worry about backwards compatibility.
This RFC proposes three alternative paths (different chains might choose to follow different paths):
Path A: add back the same memory limit to the runtime, like so:
#[global_allocator]
Path B: define the memory limit using the -Clink-arg=--max-memory=... flag.
Path C: don't add anything to the runtime. This is effectively the same as setting the memory limit to ~4 GiB (compared to the current default limit of 128 MiB). This solution is viable only because we're compiling for 32bits wasm rather than for example 64bits wasm. If we ever compile for 64bits wasm, this would need to be revisited.
Each parachain can choose the option that they prefer, but the author of this RFC strongly suggests either option C or B.
In case of path A, there is one situation where the behaviour pre-RFC is not equivalent to the one post-RFC: when a host function that performs an allocation (for example ext_storage_get) is called, without this RFC this allocation might fail due to reaching the maximum heap pages, while after this RFC this will always succeed. +This is most likely not a problem, as storage values aren't supposed to be larger than a few megabytes at the very maximum.
In the unfortunate event where the runtime runs out of memory, path B would make it more difficult to relax the memory limit, as we would need to re-upload the entire Wasm, compared to updating only :heappages in path A or before this RFC. +In the case where the runtime runs out of memory only in the specific event where the Wasm runtime is modified, this could brick the chain. However, this situation is no different than the thousands of other ways that a bug in the runtime can brick a chain, and there's no reason to be particularily worried about this situation in particular.
This RFC would reduce the chance of a consensus issue between clients. +The :heappages are a rather obscure feature, and it is not clear what happens in some corner cases such as the value being too large (error? clamp?) or malformed. This RFC would completely erase these questions.
In case of path A, it is unclear how performances would be affected. Path A consists in moving client-side operations to the runtime without changing these operations, and as such performance differences are expected to be minimal. Overall, we're talking about one addition/subtraction per malloc and per free, so this is more than likely completely negligible.
In case of path B and C, the performance gain would be a net positive, as this RFC strictly removes things.
This RFC would isolate the client and runtime more from each other, making it a bit easier to reason about the client or the runtime in isolation.
Not a breaking change. The runtime-side changes can be applied immediately (without even having to wait for changes in the client), then as soon as the runtime is updated, the client can be updated without any transition period. One can even consider updating the client before the runtime, as it corresponds to path C.
None.
This RFC follows the same path as https://github.com/polkadot-fellows/RFCs/pull/4 by scoping everything related to memory allocations to the runtime.
This RFC proposes adding a trivial governance track on Kusama to facilitate X (formerly known as Twitter) posts on the @kusamanetwork account. The technical aspect +of implementing this in the runtime is very inconsequential and straight-forward, though it might get more technical if the Fellowship wants to regulate this track +with a non-existent permission set. If this is implemented it would need to be followed up with:
The overall motivation for this RFC is to decentralize the management of the Kusama brand/communication channel to KSM holders. This is necessary in my opinion primarily +because of the inactivity of the account in recent history, with posts spanning weeks or months apart. I am currently unaware of who/what entity manages the Kusama +X account, but if they are affiliated with Parity or W3F this proposed solution could also offload some of the legal ramifications of making (or not making) +announcements to the public regarding Kusama. While centralized control of the X account would still be present, it could become totally moot if this RFC is implemented +and the community becomes totally autonomous in the management of Kusama's X posts.
This solution does not cover every single communication front for Kusama, but it does cover one of the largest. It also establishes a precedent for other communication channels +that could be offloaded to openGov, provided this proof-of-concept is successful.
Finally, this RFC is the epitome of experimentation that Kusama is ideal for. This proposal may spark newfound excitement for Kusama and help us realize Kusama's potential +for pushing boundaries and trying new unconventional ideas.
This idea has not been formalized by any individual (or group of) KSM holder(s). To my knowledge the socialization of this idea is contained +entirely in my recent X post here, but it is possible that an idea like this one has been discussed in +other places. It appears to me that the ecosystem would welcome a change like this which is why I am taking action to formalize the discussion.
The implementation of this idea can be broken down into 3 primary phases:
First, we begin with this RFC to ensure all feedback can be discussed and implemented in the proposal. After the Fellowship and the community come to a reasonable +agreement on the changes necessary to make this happen, the Fellowship can merge changes into Kusama's runtime to include this new track with appropriate track configurations. +As a starting point, I recommend the following track configurations:
const APP_X_POST: Curve = Curve::make_linear(7, 28, percent(50), percent(100)); +const SUP_X_POST: Curve = Curve::make_reciprocal(?, ?, percent(?), percent(?), percent(?)); + +// I don't know how to configure the make_reciprocal variables to get what I imagine for support, +// but I recommend starting at 50% support and sharply decreasing such that 1% is sufficient quarterway +// through the decision period and hitting 0% at the end of the decision period, or something like that. + + ( + 69, + pallet_referenda::TrackInfo { + name: "x_post", + max_deciding: 50, + decision_deposit: 1 * UNIT, + prepare_period: 10 * MINUTES, + decision_period: 4 * DAYS, + confirm_period: 10 * MINUTES, + min_enactment_period: 1 * MINUTES, + min_approval: APP_X_POST, + min_support: SUP_X_POST, + }, + ), +
I also recommend restricting permissions of this track to only submitting remarks or batches of remarks - that's all we'll need for its purpose. I'm not sure how +easy that is to configure, but it is important since we don't want such an agile track to be able to make highly consequential calls.
It is important that we establish the specifications of referenda that will be submitted in this track to ensure that whatever automation tool is built can easily +make posts once a referendum is enacted. As stated above, we really only need a system.remark (or batch of remarks) to indicate the contents of a proposed X post. +The most straight-forward way to do this is to require remarks to adhere to X's requirements for making posts via their API.
For example, if I wanted to propose a post that contained the text "Hello World!" I would propose a referendum in the X post track that contains the following call data: +0x0000607b2274657874223a202248656c6c6f20576f726c6421227d (i.e. system.remark('{"text": "Hello World!"}')).
0x0000607b2274657874223a202248656c6c6f20576f726c6421227d
system.remark('{"text": "Hello World!"}')
At first, we could support text posts only to prove the concept. Later on we could expand this spec to add support for media, likes, retweets, replies, polls, and +whatever other X features we want.
Once we agree on track configurations and specs for referenda in this track, the Fellowship can move forward with merging these changes into Kusama's runtime and +include them in its next release. We could also move forward with developing the necessary tools that would listen for enacted referenda to post automatically on X. +This would require coordination with whoever controls the X account; they would either need to run the tools themselves or add a third party as an authorized user to +run the tools to make posts on the account's behalf. This is a bottleneck for decentralization, but as long as the tools are run by the X account manager or by a trusted third party +it should be fine. I'm open to more decentralized solutions, but those always come at a cost of complexity.
For the tools themselves, we could open a bounty on Kusama for developers/teams to bid on. We could also just ask the community to step up with a Treasury proposal +to have anyone fund the build. Or, the Fellowship could make the release of these changes contingent on their endorsement of developers/teams to build these tools. Lots of options! +For the record, me and my team could develop all the necessary tools, but all because I'm proposing these changes doesn't entitle me to funds to build the tools needed +to implement them. Here's what would be needed:
After everything is complete, we can update the Kusama wiki to include documentation on the X post specifications and include links to the tools/UI.
The main drawback to this change is that it requires a lot of off-chain coordination. It's easy enough to include the track on Kusama but it's a totally different +challenge to make it function as intended. The tools need to be built and the auth tokens need to be managed. It would certainly add an administrative burden to whoever +manages the X account since they would either need to run the tools themselves or manage auth tokens.
This change also introduces on-going costs to the Treasury since it would need to compensate people to support the tools necessary to facilitate this idea. The ultimate +question is whether these on-going costs would be worth the ability for KSM holders to make posts on Kusama's X account.
There's also the risk of misconfiguring the track to make referenda too easy to pass, potentially allowing a malicious actor to get content posted on X that violates X's ToS. +If that happens, we risk getting Kusama banned on X!
This change might also be outside the scope of the Fellowship/openGov. Perhaps the best solution for the X account is to have the Treasury pay for a professional +agency to manage posts. It wouldn't be decentralized but it would probably be more effective in terms of creating good content.
Finally, this solution is merely pseudo-decentralization since the X account manager would still have ultimate control of the account. It's decentralized insofar as +the auth tokens are given to people actually running the tools; a house of cards is required to facilitate X posts via this track. Not ideal.
There's major precedent for configuring tracks on openGov given the amount of power tracks have, so it shouldn't be hard to come up with a sound configuration. +That's why I recommend restricting permissions of this track to remarks and batches of remarks, or something equally inconsequential.
Building the tools for this implementation is really straight-forward and could be audited by Fellowship members, and the community at large, on Github.
The largest security concern would be the management of Kusama's X account's auth tokens. We would need to ensure that they aren't compromised.
If a track on Kusama promises users that compliant referenda enacted therein would be posted on Kusama's X account, users would expect that track to perform as promised. +If the house of cards tumbles down and a compliant referendum doesn't actually get anything posted, users might think that Kusama is broken or unreliable. This +could be damaging to Kusama's image and cause people to question the soundness of other features on Kusama.
As mentioned in the drawbacks, the performance of this feature would depend on off-chain coordinations. We can reduce the administrative burden of these coordinations +by funding third parties with the Treasury to deal with it, but then we're relying on trusting these parties.
By adding a new track to Kusama, governance platforms like Polkassembly or Nova Wallet would need to include it on their applications. This shouldn't be too +much of a burden or overhead since they've already built the infrastructure for other openGov tracks.
This change wouldn't break any compatibility as far as I know.
One reference to a similar feature requiring on-chain/off-chain coordination would be the Kappa-Sigma-Mu Society. Nothing on-chain necessarily enforces the rules +or facilitates bids, challenges, defenses, etc. However, the Society has managed to maintain itself with integrity to its rules. So I don't think this is totally +out of Kusama's scope. But it will require some off-chain effort to maintain.
The current size of the decision deposit on some tracks is too high for many proposers. As a result, those needing to use it have to find someone else willing to put up the deposit for them - and a number of legitimate attempts to use the root track have timed out. This track would provide a more affordable (though slower) route for these holders to use the root track.
There have been recent attempts to use the Kusama root track which have timed out with no decision deposit placed. Usually, these referenda have been related to parachain registration related issues.
Propose to address this by adding a new referendum track [22] Referendum Deposit which can place the decision deposit on another referendum. This would require the following changes:
placeDecisionDesposit
referenda->placeDecisionDeposit
This track would provide a route to starting a root referendum with a much-reduced slashable deposit. This might be undesirable but, assuming the decision deposit cost for this track is still high enough, slashing would still act as a disincentive.
An alternative to this might be to reduce the decision deposit size some of the more expensive tracks. However, part of the purpose of the high deposit - at least on the root track - is to prevent spamming the limited queue with junk referenda.
Will need additional tests case for the modified pallet and runtime. No security or privacy issues.
No significant performance impact.
Only changes related to adding the track. Existing functionality is unchanged.
No compatibility issues.
Feedback on whether my proposed implementation of this is the best way to address the issue - including which calls the track should be allowed to make. Are the track parameters correct or should be use something different? Alternative would be welcome.
A pallet to facilitate enhanced multisig accounts. The main enhancement is that we store a multisig account in the state with related info (signers, threshold,..etc). The module affords enhanced control over administrative operations such as adding/removing signers, changing the threshold, account deletion, canceling an existing proposal. Each signer can approve/reject a proposal while still exists. The proposal is not intended for migrating or getting rid of existing multisig. It's to allow both options to coexist.
For the rest of the RFC We use the following terms:
proposal
Stateful Multisig
Stateless Multisig
Entities in the Polkadot ecosystem need to have a way to manage their funds and other operations in a secure and efficient way. Multisig accounts are a common way to achieve this. Entities by definition change over time, members of the entity may change, threshold requirements may change, and the multisig account may need to be deleted. For even more enhanced hierarchical control, the multisig account may need to be controlled by other multisig accounts.
Current native solutions for multisig operations are less optimal, performance-wise (as we'll explain later in the RFC), and lack fine-grained control over the multisig account.
We refer to current multisig pallet in polkadot-sdk because the multisig account is only derived and not stored in the state. Although deriving the account is determinsitc as it relies on exact users (sorted) and thershold to derive it. This does not allow for control over the multisig account. It's also tightly coupled to exact users and threshold. This makes it hard for an organization to manage existing accounts and to change the threshold or add/remove signers.
We believe as well that the stateless multisig is not efficient in terms of block footprint as we'll show in the performance section.
Pure proxy can achieve having a stored and determinstic multisig account from different users but it's unneeded complexity as a way around the limitations of the current multisig pallet. It doesn't also have the same fine grained control over the multisig account.
Other points mentioned by @tbaut
Basic requirements for the Stateful Multisig are:
Corporate Governance: +In a corporate setting, multisig accounts can be employed for decision-making processes. For example, a company may require the approval of multiple executives to initiate significant financial transactions.
Joint Accounts: +Multisig accounts can be used for joint accounts where multiple individuals need to authorize transactions. This is particularly useful in family finances or shared business accounts.
Decentralized Autonomous Organizations (DAOs): +DAOs can utilize multisig accounts to ensure that decisions are made collectively. Multiple key holders can be required to approve changes to the organization's rules or the allocation of funds.
and much more...
I've created the stateful multisig pallet during my studies in Polkadot Blockchain Academy under supervision from @shawntabrizi and @ank4n. After that, I've enhanced it to be fully functional and this is a draft PR#3300 in polkadot-sdk. I'll list all the details and design decisions in the following sections. Note that the PR is not 1-1 exactly to the current RFC as the RFC is a more polished version of the PR after updating based on the feedback and discussions.
Let's start with a sequence diagram to illustrate the main operations of the Stateful Multisig.
Notes on above diagram:
Execute
having the following enum to store the call or the hash:
#![allow(unused)] +fn main() { +enum CallOrHash<T: Config> { + Call(<T as Config>::RuntimeCall), + Hash(T::Hash), +} +}
create_multisig
#![allow(unused)] +fn main() { + /// Creates a new multisig account and attach signers with a threshold to it. + /// + /// The dispatch origin for this call must be _Signed_. It is expected to be a nomral AccountId and not a + /// Multisig AccountId. + /// + /// T::BaseCreationDeposit + T::PerSignerDeposit * signers.len() will be held from the caller's account. + /// + /// # Arguments + /// + /// - `signers`: Initial set of accounts to add to the multisig. These may be updated later via `add_signer` + /// and `remove_signer`. + /// - `threshold`: The threshold number of accounts required to approve an action. Must be greater than 0 and + /// less than or equal to the total number of signers. + /// + /// # Errors + /// + /// * `TooManySignatories` - The number of signatories exceeds the maximum allowed. + /// * `InvalidThreshold` - The threshold is greater than the total number of signers. + pub fn create_multisig( + origin: OriginFor<T>, + signers: BoundedBTreeSet<T::AccountId, T::MaxSignatories>, + threshold: u32, + ) -> DispatchResult +}
start_proposal
#![allow(unused)] +fn main() { + /// Starts a new proposal for a dispatchable call for a multisig account. + /// The caller must be one of the signers of the multisig account. + /// T::ProposalDeposit will be held from the caller's account. + /// + /// # Arguments + /// + /// * `multisig_account` - The multisig account ID. + /// * `call_or_hash` - The enum having the call or the hash of the call to be approved and executed later. + /// + /// # Errors + /// + /// * `MultisigNotFound` - The multisig account does not exist. + /// * `UnAuthorizedSigner` - The caller is not an signer of the multisig account. + /// * `TooManySignatories` - The number of signatories exceeds the maximum allowed. (shouldn't really happen as it's the first approval) + pub fn start_proposal( + origin: OriginFor<T>, + multisig_account: T::AccountId, + call_or_hash: CallOrHash, + ) -> DispatchResult +}
approve
#![allow(unused)] +fn main() { + /// Approves a proposal for a dispatchable call for a multisig account. + /// The caller must be one of the signers of the multisig account. + /// + /// If a signer did approve -> reject -> approve, the proposal will be approved. + /// If a signer did approve -> reject, the proposal will be rejected. + /// + /// # Arguments + /// + /// * `multisig_account` - The multisig account ID. + /// * `call_or_hash` - The enum having the call or the hash of the call to be approved. + /// + /// # Errors + /// + /// * `MultisigNotFound` - The multisig account does not exist. + /// * `UnAuthorizedSigner` - The caller is not an signer of the multisig account. + /// * `TooManySignatories` - The number of signatories exceeds the maximum allowed. + /// This shouldn't really happen as it's an approval, not an addition of a new signer. + pub fn approve( + origin: OriginFor<T>, + multisig_account: T::AccountId, + call_or_hash: CallOrHash, + ) -> DispatchResult +}
reject
#![allow(unused)] +fn main() { + /// Rejects a proposal for a multisig account. + /// The caller must be one of the signers of the multisig account. + /// + /// Between approving and rejecting, last call wins. + /// If a signer did approve -> reject -> approve, the proposal will be approved. + /// If a signer did approve -> reject, the proposal will be rejected. + /// + /// # Arguments + /// + /// * `multisig_account` - The multisig account ID. + /// * `call_or_hash` - The enum having the call or the hash of the call to be rejected. + /// + /// # Errors + /// + /// * `MultisigNotFound` - The multisig account does not exist. + /// * `UnAuthorizedSigner` - The caller is not an signer of the multisig account. + /// * `SignerNotFound` - The caller has not approved the proposal. + #[pallet::call_index(3)] + #[pallet::weight(Weight::default())] + pub fn reject( + origin: OriginFor<T>, + multisig_account: T::AccountId, + call_or_hash: CallOrHash, + ) -> DispatchResult +}
execute_proposal
#![allow(unused)] +fn main() { + /// Executes a proposal for a dispatchable call for a multisig account. + /// Poropsal needs to be approved by enough signers (exceeds or equal multisig threshold) before it can be executed. + /// The caller must be one of the signers of the multisig account. + /// + /// This function does an extra check to make sure that all approvers still exist in the multisig account. + /// That is to make sure that the multisig account is not compromised by removing an signer during an active proposal. + /// + /// Once finished, the withheld deposit will be returned to the proposal creator. + /// + /// # Arguments + /// + /// * `multisig_account` - The multisig account ID. + /// * `call_or_hash` - We should have gotten the RuntimeCall (preimage) and stored it in the proposal by the time the extrinsic is called. + /// + /// # Errors + /// + /// * `MultisigNotFound` - The multisig account does not exist. + /// * `UnAuthorizedSigner` - The caller is not an signer of the multisig account. + /// * `NotEnoughApprovers` - approvers don't exceed the threshold. + /// * `ProposalNotFound` - The proposal does not exist. + /// * `CallPreImageNotFound` - The proposal doesn't have the preimage of the call in the state. + pub fn execute_proposal( + origin: OriginFor<T>, + multisig_account: T::AccountId, + call_or_hash: CallOrHash, + ) -> DispatchResult +}
cancel_proposal
#![allow(unused)] +fn main() { + /// Cancels an existing proposal for a multisig account. + /// Poropsal needs to be rejected by enough signers (exceeds or equal multisig threshold) before it can be executed. + /// The caller must be one of the signers of the multisig account. + /// + /// This function does an extra check to make sure that all rejectors still exist in the multisig account. + /// That is to make sure that the multisig account is not compromised by removing an signer during an active proposal. + /// + /// Once finished, the withheld deposit will be returned to the proposal creator./ + /// + /// # Arguments + /// + /// * `origin` - The origin multisig account who wants to cancel the proposal. + /// * `call_or_hash` - The call or hash of the call to be canceled. + /// + /// # Errors + /// + /// * `MultisigNotFound` - The multisig account does not exist. + /// * `ProposalNotFound` - The proposal does not exist. + pub fn cancel_proposal( + origin: OriginFor<T>, + multisig_account: T::AccountId, + call_or_hash: CallOrHash) -> DispatchResult +}
cancel_own_proposal
#![allow(unused)] +fn main() { + /// Cancels an existing proposal for a multisig account Only if the proposal doesn't have approvers other than + /// the proposer. + /// + /// This function needs to be called from a the proposer of the proposal as the origin. + /// + /// The withheld deposit will be returned to the proposal creator. + /// + /// # Arguments + /// + /// * `multisig_account` - The multisig account ID. + /// * `call_or_hash` - The hash of the call to be canceled. + /// + /// # Errors + /// + /// * `MultisigNotFound` - The multisig account does not exist. + /// * `ProposalNotFound` - The proposal does not exist. + pub fn cancel_own_proposal( + origin: OriginFor<T>, + multisig_account: T::AccountId, + call_or_hash: CallOrHash, + ) -> DispatchResult +}
cleanup_proposals
#![allow(unused)] +fn main() { + /// Cleanup proposals of a multisig account. This function will iterate over a max limit per extrinsic to ensure + /// we don't have unbounded iteration over the proposals. + /// + /// The withheld deposit will be returned to the proposal creator. + /// + /// # Arguments + /// + /// * `multisig_account` - The multisig account ID. + /// + /// # Errors + /// + /// * `MultisigNotFound` - The multisig account does not exist. + /// * `ProposalNotFound` - The proposal does not exist. + pub fn cleanup_proposals( + origin: OriginFor<T>, + multisig_account: T::AccountId, + ) -> DispatchResult +}
Note: Next functions need to be called from the multisig account itself. Deposits are reserved from the multisig account as well.
add_signer
#![allow(unused)] +fn main() { + /// Adds a new signer to the multisig account. + /// This function needs to be called from a Multisig account as the origin. + /// Otherwise it will fail with MultisigNotFound error. + /// + /// T::PerSignerDeposit will be held from the multisig account. + /// + /// # Arguments + /// + /// * `origin` - The origin multisig account who wants to add a new signer to the multisig account. + /// * `new_signer` - The AccountId of the new signer to be added. + /// * `new_threshold` - The new threshold for the multisig account after adding the new signer. + /// + /// # Errors + /// * `MultisigNotFound` - The multisig account does not exist. + /// * `InvalidThreshold` - The threshold is greater than the total number of signers or is zero. + /// * `TooManySignatories` - The number of signatories exceeds the maximum allowed. + pub fn add_signer( + origin: OriginFor<T>, + new_signer: T::AccountId, + new_threshold: u32, + ) -> DispatchResult +}
remove_signer
#![allow(unused)] +fn main() { + /// Removes an signer from the multisig account. + /// This function needs to be called from a Multisig account as the origin. + /// Otherwise it will fail with MultisigNotFound error. + /// If only one signer exists and is removed, the multisig account and any pending proposals for this account will be deleted from the state. + /// + /// # Arguments + /// + /// * `origin` - The origin multisig account who wants to remove an signer from the multisig account. + /// * `signer_to_remove` - The AccountId of the signer to be removed. + /// * `new_threshold` - The new threshold for the multisig account after removing the signer. Accepts zero if + /// the signer is the only one left.kkk + /// + /// # Errors + /// + /// This function can return the following errors: + /// + /// * `MultisigNotFound` - The multisig account does not exist. + /// * `InvalidThreshold` - The new threshold is greater than the total number of signers or is zero. + /// * `UnAuthorizedSigner` - The caller is not an signer of the multisig account. + pub fn remove_signer( + origin: OriginFor<T>, + signer_to_remove: T::AccountId, + new_threshold: u32, + ) -> DispatchResult +}
set_threshold
#![allow(unused)] +fn main() { + /// Sets a new threshold for a multisig account. + /// This function needs to be called from a Multisig account as the origin. + /// Otherwise it will fail with MultisigNotFound error. + /// + /// # Arguments + /// + /// * `origin` - The origin multisig account who wants to set the new threshold. + /// * `new_threshold` - The new threshold to be set. + /// # Errors + /// + /// * `MultisigNotFound` - The multisig account does not exist. + /// * `InvalidThreshold` - The new threshold is greater than the total number of signers or is zero. + set_threshold(origin: OriginFor<T>, new_threshold: u32) -> DispatchResult +}
delete_multisig
#![allow(unused)] +fn main() { + /// Deletes a multisig account and all related proposals. + /// + /// This function needs to be called from a Multisig account as the origin. + /// Otherwise it will fail with MultisigNotFound error. + /// + /// # Arguments + /// + /// * `origin` - The origin multisig account who wants to cancel the proposal. + /// + /// # Errors + /// + /// * `MultisigNotFound` - The multisig account does not exist. + pub fn delete_account(origin: OriginFor<T>) -> DispatchResult +}
#![allow(unused)] +fn main() { +#[pallet::storage] + pub type MultisigAccount<T: Config> = StorageMap<_, Twox64Concat, T::AccountId, MultisigAccountDetails<T>>; + +/// The set of open multisig proposals. A proposal is uniquely identified by the multisig account and the call hash. +/// (maybe a nonce as well in the future) +#[pallet::storage] +pub type PendingProposals<T: Config> = StorageDoubleMap< + _, + Twox64Concat, + T::AccountId, // Multisig Account + Blake2_128Concat, + T::Hash, // Call Hash + MultisigProposal<T>, +>; +}
As for the values:
#![allow(unused)] +fn main() { +pub struct MultisigAccountDetails<T: Config> { + /// The signers of the multisig account. This is a BoundedBTreeSet to ensure faster operations (add, remove). + /// As well as lookups and faster set operations to ensure approvers is always a subset from signers. (e.g. in case of removal of an signer during an active proposal) + pub signers: BoundedBTreeSet<T::AccountId, T::MaxSignatories>, + /// The threshold of approvers required for the multisig account to be able to execute a call. + pub threshold: u32, + pub deposit: BalanceOf<T>, +} +}
#![allow(unused)] +fn main() { +pub struct MultisigProposal<T: Config> { + /// Proposal creator. + pub creator: T::AccountId, + pub creation_deposit: BalanceOf<T>, + /// The extrinsic when the multisig operation was opened. + pub when: Timepoint<BlockNumberFor<T>>, + /// The approvers achieved so far, including the depositor. + /// The approvers are stored in a BoundedBTreeSet to ensure faster lookup and operations (approve, reject). + /// It's also bounded to ensure that the size don't go over the required limit by the Runtime. + pub approvers: BoundedBTreeSet<T::AccountId, T::MaxSignatories>, + /// The rejectors for the proposal so far. + /// The rejectors are stored in a BoundedBTreeSet to ensure faster lookup and operations (approve, reject). + /// It's also bounded to ensure that the size don't go over the required limit by the Runtime. + pub rejectors: BoundedBTreeSet<T::AccountId, T::MaxSignatories>, + /// The block number until which this multisig operation is valid. None means no expiry. + pub expire_after: Option<BlockNumberFor<T>>, +} +}
For optimization we're using BoundedBTreeSet to allow for efficient lookups and removals. Especially in the case of approvers, we need to be able to remove an approver from the list when they reject their approval. (which we do lazily when execute_proposal is called).
There's an extra storage map for the deposits of the multisig accounts per signer added. This is to ensure that we can release the deposits when the multisig removes them even if the constant deposit per signer changed in the runtime later on.
We need to ensure that the approvers are always a subset from signers. This is also partially why we're using BoundedBTreeSet for signers and approvers. Once execute proposal is called we ensure that the proposal is still valid and the approvers are still a subset from current signers.
Once the last signer of a multisig account is removed or the multisig approved the account deletion we delete the multisig accound from the state and keep the proposals until someone calls cleanup_proposals multiple times which iterates over a max limit per extrinsic. This is to ensure we don't have unbounded iteration over the proposals. Users are already incentivized to call cleanup_proposals to get their deposits back.
We currently just delete the account without checking for deposits (Would like to hear your thoughts here). We can either
We always use latest threshold and don't store each proposal with different threshold. This allows the following:
Standard audit/review requirements apply.
Doing back of the envelop calculation to proof that the stateful multisig is more efficient than the stateless multisig given it's smaller footprint size on blocks.
Quick review over the extrinsics for both as it affects the block size:
Stateless Multisig: +Both as_multi and approve_as_multi has a similar parameters:
as_multi
approve_as_multi
#![allow(unused)] +fn main() { +origin: OriginFor<T>, +threshold: u16, +other_signatories: Vec<T::AccountId>, +maybe_timepoint: Option<Timepoint<BlockNumberFor<T>>>, +call_hash: [u8; 32], +max_weight: Weight, +}
Stateful Multisig: +We have the following extrinsics:
#![allow(unused)] +fn main() { +pub fn start_proposal( + origin: OriginFor<T>, + multisig_account: T::AccountId, + call_or_hash: CallOrHash, + ) +}
#![allow(unused)] +fn main() { +pub fn approve( + origin: OriginFor<T>, + multisig_account: T::AccountId, + call_or_hash: CallOrHash, + ) +}
#![allow(unused)] +fn main() { +pub fn execute_proposal( + origin: OriginFor<T>, + multisig_account: T::AccountId, + call_or_hash: CallOrHash, + ) +}
The main takeway is that we don't need to pass the threshold and other signatories in the extrinsics. This is because we already have the threshold and signatories in the state (only once).
So now for the caclulations, given the following:
The table calculates if each of the K multisig accounts has one proposal and it gets approved by the 2N/3 and then executed. How much did the total Blocks and States sizes increased by the end of the day.
Note: We're not calculating the cost of proposal as both in statefull and stateless multisig they're almost the same and gets cleaned up from the state once the proposal is executed or canceled.
Stateless effect on blocksizes = 2/3KN^2 (as each user of the 2/3 users will need to call approve_as_multi with all the other signatories(N) in extrinsic body)
Stateful effect on blocksizes = K * N (as each user will need to call approve with the multisig account only in extrinsic body)
Stateless effect on statesizes = Nil (as the multisig account is not stored in the state)
Stateful effect on statesizes = K*N (as each multisig account (K) will be stored with all the signers (K) in the state)
Simplified table removing K from the equation: +| Pallet | Block Size | State Size | +|----------------|:-------------:|-----------:| +| Stateless | N^2 | Nil | +| Stateful | N | N |
So even though the stateful multisig has a larger state size, it's still more efficient in terms of block size and total footprint on the blockchain.
The Stateful Multisig will have better ergonomics for managing multisig accounts for both developers and end-users.
This RFC is compatible with the existing implementation and can be handled via upgrades and migration. It's not intended to replace the existing multisig pallet.
multisig pallet in polkadot-sdk
This proposes to increase the maximum length of PGP Fingerprint values from a 20 bytes/chars limit to a 40 bytes/chars limit.
Pretty Good Privacy (PGP) Fingerprints are shorter versions of their corresponding Public Key that may be printed on a business card.
They may be used by someone to validate the correct corresponding Public Key.
It should be possible to add PGP Fingerprints to Polkadot on-chain identities.
GNU Privacy Guard (GPG) is compliant with PGP and the two acronyms are used interchangeably.
If you want to set a Polkadot on-chain identity, users may provide a PGP Fingerprint value in the "pgpFingerprint" field, which may be longer than 20 bytes/chars (e.g. PGP Fingerprints are 40 bytes/chars long), however that field can only store a maximum length of 20 bytes/chars of information.
Possible disadvantages of the current 20 bytes/chars limitation:
identity
setIdentity(info)
The maximum length of identity PGP Fingerprint values should be increased from the current 20 bytes/chars limit at least a 40 bytes/chars limit to support PGP Fingerprints and GPG Fingerprints.
If a user tries to setting an on-chain identity by creating an extrinsic using Polkadot.js with identity > setIdentity(info), then if they try to provide their 40 character long PGP Fingerprint or GPG Fingerprint, which is longer than the maximum length of 20 bytes/chars [u8;20], then they will encounter this error:
[u8;20]
createType(Call):: Call: failed decoding identity.setIdentity:: Struct: failed on args: {...}:: Struct: failed on pgpFingerprint: Option<[u8;20]>:: Expected input with 20 bytes (160 bits), found 40 bytes +
Increasing maximum length of identity PGP Fingerprint values from the current 20 bytes/chars limit to at least a 40 bytes/chars limit would overcome these errors and support PGP Fingerprints and GPG Fingerprints, satisfying the solution requirements.
No drawbacks have been identified.
Implementations would be tested for adherance by checking that 40 bytes/chars PGP Fingerprints are supported.
No effect on security or privacy has been identified than already exists.
No implementation pitfalls have been identified.
It would be an optimization, since the associated exposed interfaces to developers and end-users could start being used.
To minimize additional overhead the proposal suggests a 40 bytes/chars limit since that would at least provide support for PGP Fingerprints, satisfying the solution requirements.
No potential ergonomic optimizations have been identified.
Updates to Polkadot.js Apps, API and its documentation and those referring to it may be required.
No prior articles or references.
No further questions at this stage.
Relates to RFC entitled "Increase maximum length of identity raw data values from 32 bytes".
This proposes to require a slashable deposit in the broker pallet when initially purchasing or renewing Bulk Coretime or Instantaneous Coretime cores.
Additionally, it proposes to record a reputational status based on the behavior of the purchaser, as it relates to their use of Kusama Coretime cores that they purchase, and to possibly reserve a proportion of the cores for prospective purchasers that have an on-chain identity.
There are sales of Kusama Coretime cores that are scheduled to occur later this month by Coretime Marketplace Lastic.xyz initially in limited quantities, and potentially also by RegionX in future that is subject to their Polkadot referendum #582. This poses a risk in that some Kusama Coretime core purchasers may buy Kusama Coretime cores when they have no intention of actually placing a workload on them or leasing them out, which would prevent those that wish to purchase and actually use Kusama Coretime cores from being able to use any at cores at all.
The types of purchasers may include:
Chaoatic repurcussions could include the following:
On-chain identity. It may be possible to circumvent bots and scalpers to an extent by requiring a proportion of Kusama Coretime purchasers to have an on-chain identity. As such, a possible solution could be to allow the configuration of a threshold in the Broker pallet that reserves a proportion of the cores for accounts that have an on-chain identity, that reverts to a waiting list of anonymous account purchasers if the reserved proportion of cores remain unsold.
Slashable deposit. A viable solution could be to require a slashable deposit to be locked prior to the purchase or renewal of a core, similar to how decision deposits are used in OpenGov to prevent spam, but where if you buy a Kusama Coretime core you could be challenged by one of more collectives of fishermen to provide proof against certain criteria of how you used it, and if you fail to provide adequate evidence in response to that scrutiny, then you would lose a proportion of that deposit and face restrictions on purchasing or renewing cores in future that may also be configured on-chain.
Reputation. To disincentivise certain behaviours, a reputational status indicator could be used to record the historic behavior of the purchaser and whether on-chain judgement has determined they have adequately rectified that behaviour, as it relates to their usage of Kusama Coretime cores that they purchase.
The slashable deposit if set too high, may result in an economic impact, where less Kusama Coretime core sales are purchased.
Lack of a slashable deposit in the Broker pallet is a security concern, since it exposes Kusama Coretime sales to potential abuse.
Reserving a proportion of Kusama Coretime sales cores for those with on-chain identities should not be to the exclusion of accounts that wish to remain anonymous or cause cores to be wasted unnecessarily. As such, if cores that are reserved for on-chain identities remain unsold then they should be released to anonymous accounts that are on a waiting list.
It should improve performance as it reduces the potential for state bloat since there is less risk of undesirable Kusama Coretime sales activity that would be apparent with no requirement for a slashable deposit or there being no reputational risk to purchasers that waste or misuse Kusama Coretime cores.
The solution proposes to minimize the risk of some Kusama Coretime cores not even being used or leased to perform any tasks at all.
It will be important to monitor and manage the slashable deposits, purchaser reputations, and utilization of the proportion of cores that are reserved for accounts with an on-chain identity.
The mechanism for setting a slashable deposit amount, should avoid undue complexity for users.
No prior articles.
This RFC proposes the addition of a secondary market feature to either the broker pallet or as a separate pallet maintained by Lastic, enabling users to list and purchase regions. This includes creating, purchasing, and removing listings, as well as emitting relevant events and handling associated errors.
Currently, the broker pallet lacks functionality for a secondary market, which limits users' ability to freely trade regions. This RFC aims to introduce a secure and straightforward mechanism for users to list regions they own for sale and allow other users to purchase these regions.
While integrating this functionality directly into the broker pallet is one option, another viable approach is to implement it as a separate pallet maintained by Lastic. This separate pallet would have access to the broker pallet and add minimal functionality necessary to support the secondary market.
Adding smart contracts to the Coretime chain could also address this need; however, this process is expected to be lengthy and complex. We cannot afford to wait for this extended timeline to enable basic secondary market functionality. By proposing either integration into the broker pallet or the creation of a dedicated pallet, we can quickly enhance the flexibility and utility of the broker pallet, making it more user-friendly and valuable.
Primary stakeholders include:
This RFC introduces the following key features:
Storage Changes:
Listings
New Dispatchable Functions:
create_listing
purchase_listing
remove_listing
Events:
ListingCreated
RegionSold
ListingRemoved
Error Handling:
ExpiredRegion
UnknownListing
InvalidPrice
NotOwner
Testing:
The main drawback of adding the additional complexity directly to the broker pallet is the potential increase in maintenance overhead. Therefore, we propose adding additional functionality as a separate pallet on the Coretime chain. To take the pressure off from implementing these features, implementation along with unit tests would be taken care of by Lastic (Aurora Makovac, Philip Lucsok).
There are potential risks of security vulnerabilities in the new market functionalities, such as unauthorized region transfers or incorrect balance adjustments. Therefore, extensive security measures would have to be implemented.
This RFC proposes the integration of smart contracts on the Coretime chain to enhance flexibility and enable complex decentralized applications, including secondary market functionalities.
Currently, the Coretime chain lacks the capability to support smart contracts, which limits the range of decentralized applications that can be developed and deployed. By enabling smart contracts, the Coretime chain can facilitate more sophisticated functionalities such as automated region trading, dynamic pricing mechanisms, and other decentralized applications that require programmable logic. This will enhance the utility of the Coretime chain, attract more developers, and create more opportunities for innovation.
Additionally, while there is a proposal (#885) to allow EVM-compatible contracts on Polkadot’s Asset Hub, the implementation of smart contracts directly on the Coretime chain will provide synchronous interactions and avoid the complexities of asynchronous operations via XCM.
This RFC introduces the following key components:
Smart Contract Support:
Storage and Execution:
Integration with Existing Pallets:
Security and Auditing:
There are several drawbacks to consider:
By enabling smart contracts on the Coretime chain, we can significantly expand its capabilities and attract a wider range of developers and users, fostering innovation and growth in the ecosystem.
RequestCodeUpgrade
Change the upgrade process of a parachain runtime upgrade to become an off-chain +process with regards to the relay chain. Upgrades are still contained in +parachain blocks, but will no longer need to end up in relay chain blocks nor in +relay chain state.
Having parachain runtime upgrades go through the relay chain has always been +seen as a scalability concern. Due to optimizations in statement +distribution and asynchronous backing it became less crucial and got +de-prioritized, the original issue can be found +here.
With the introduction of Agile Coretime and in general our efforts to reduce +barrier to entry more for Polkadot more, the issue becomes more relevant again: +We would like to reduce the required storage deposit for PVF registration, with +the aim to not only make it cheaper to run a parachain (bulk + on-demand +coretime), but also reduce the amount of capital required for the deposit. With +this we would hope for far more parachains to get registered, thousands +potentially even ten thousands. With so many PVFs registered, updates are +expected to become more frequent and even attacks on service quality for other +parachains would become a higher risk.
The issues with on-chain runtime upgrades are:
We discussed introducing a separate signalling before submitting the actual +runtime, but I think we should just go one step further and make upgrades fully +off-chain. Which also helps bringing down deposit costs in a secure way, as we +are also actually reducing costs for the network.
As part of elastic scaling we are already planning to increase flexibility of UMP +messages, we can now use this to our advantage and introduce another UMP message:
#![allow(unused)] +fn main() { +enum UMPSignal { + // For elastic scaling + OnCore(CoreIndex), + // For off-chain upgrades + RequestCodeUpgrade(Hash), +} +}
We could also make that new message a regular XCM, calling an extrinsic on the +relay chain, but we will want to look into that message right after validation +on the backers on the node side, making a straight forward semantic message more +apt for the purpose.
We will introduce a new request/response protocol for both collators and +validators, with the following request/response:
#![allow(unused)] +fn main() { +struct RequestBlob { + blob_hash: Hash, +} + +struct BlobResponse { + blob: Vec<u8> +} +}
This protocol will be used by backers to request the PVF from collators in the +following conditions:
In case they received the collation via PoV distribution instead of from the +collator itself, they will use the exact same message to fetch from the valiator +they got the PoV from.
Once the candidate issuing RequestCodeUpgrade got backed on chain, validators +will start fetching the code from the backers as part of availability +distribution.
To mitigate attack vectors we should make sure that serving requests for code +can be treated as low priority requests. Thus I am suggesting the following +scheme:
Validators will notice via a runtime API (TODO: Define) that a new code has been requested, the +API will return the Hash and a counter, which starts at some configurable +value e.g. 10. The validators are now aware of the new hash and start fetching, +but they don't have to wait for the fetch to succeed to sign their bitfield.
Hash
Then on each further candidate from that chain that counter gets decremented. +Validators which have not yet succeeded fetching will now try again. This game +continues until the counter reached 0. Now it is mandatory to have to code in +order to sign a 1 in the bitfield.
PVF pre-checking will happen after the candidate which brought the counter to +0 has been successfully included and thus is also able to assume that 2/3 of +the validators have the code.
This scheme serves two purposes:
First when a candidate is backed we need to make the new hash available +(together with a counter) via a +runtime API so validators in availability distribution can check for it and +fetch it if changed (see previous section). For performance reasons, I think we +should not do an additional call, but replace the existing one with one containing the new additional information (Option<(Hash, Counter)>).
Once the candidate gets included (counter 0), the hash is given to pre-checking +and only after pre-checking succeeded (and a full session passed) it is finally +enacted and the parachain can switch to the new code. (Same process as it used +to be.)
If a backer receives a collation for a parachain it does not yet have the code +as enacted on chain (see "On-chain code upgrade process"), it will use above +request/response protocol to fetch it from whom it received the collation.
Validators in availability distribution will be changed to only sign a 1 in +the bitfield of a candidate if they not only have the chunk, but also the +currently active PVF. They will fetch it from backers in case they don't have it +yet.
Two ways:
We covered how validators get hold of new code, but when can they prune old ones? +In principle it is not an issue, if some validors prune code, because:
But the majority of validators should always keep the latest code of any +parachain and only prune the previous one, once the first candidate using the +new code got finalized. This ensures that disputes will always be able to +resolve.
The major drawback of this solution is the same as any solution the moves work +off-chain, it adds complexity to the node. E.g. nodes needing the PVF, need to +store them separately, together with their own pruning strategy as well.
Implementations adhering to this RFC, will respond to PVF requests with the +actual PVF, if they have it. Requesters will persist received PVFs on disk for +as long as they are replaced by a new one. Implementations must not be lazy +here, if validators only fetched the PVF when needed, they can be prevented from +participating in disputes.
Validators should treat incoming requests for PVFs in general with rather low +priority, but should prefer fetches from other validators over requests from +random peers.
Given that we are altering what set bits in the availability bitfields mean (not +only chunk, but also PVF available), it is important to have enough validators +upgraded, before we allow collators to make use of the new runtime upgrade +mechanism. Otherwise we would risk disputes to not being able to succeed.
This RFC has no impact on privacy.
This proposal lightens the load on the relay chain and is thus in general +beneficial for the performance of the network, this is achieved by the +following:
End users are only affected by better performance and more stable block times. +Parachains will need to implement the introduced request/response protocol and +adapt to the new signalling mechanism via an UMP message, instead of sending +the code upgrade directly.
UMP
For parachain operators we should emit events on initiated runtime upgrade and +each block reporting the current counter and how many blocks to go until the +upgrade gets passed to pre-checking. This is especially important for on-demand +chains or bulk users not occupying a full core. Further more that behaviour of +requiring multiple blocks to fully initiate a runtime upgrade needs to be well +documented.
We will continue to support the old mechanism for code upgrades for a while, but +will start to impose stricter limits over time, with the number of registered +parachains going up. With those limits in place parachains not migrating to the +new scheme might be having a harder time upgrading and will miss more blocks. I +guess we can be lenient for a while still, so the upgrade path for +parachains should be rather smooth.
In total the protocol changes we need are:
For validators and collators:
Only for validators:
Off-chain runtime upgrades have been discussed before, the architecture +described here is simpler though as it piggybacks on already existing features, +namely:
I have code
https://github.com/paritytech/polkadot-sdk/issues/971
TODO: Fully resolve these questions and incorporate in RFC text.
By no longer having code upgrade go through the relay chain, occupying a full relay +chain block, the impact on other parachains is already greatly reduced, if we +make distribution and PVF pre-checking low-priority processes on validators. The +only thing attackers might be able to do is delay upgrades of other parachains.
Which seems like a problem to be solved once we actually see it as a problem in +the wild (and can already be mitigated by adjusting the counter). The good thing +is that we have all the ingredients to go further if need be. Signalling no +longer actually includes the code, hence there is no need to reject the +candidate: The parachain can make progress even if we choose not to immediately +act on the request and no relay chain resources are wasted either.
We could for example introduce another UMP Signalling message +RequestCodeUpgradeWithPriority which not just requests a code upgrade, but +also offers some DOT to get ranked up in a queue.
RequestCodeUpgradeWithPriority
Making this storage mechanism more general purpose is worth thinking about. E.g. +by resolving above "fee" question, we might also be able to resolve the pruning +question in a more generic way and thus could indeed open this storage facility +for other purposes as well. E.g. smart contracts, so the PoV would only need to +reference contracts by hash and the actual PoV is stored on validators and +collators and thus no longer needs to be part of the PoV.
A possible avenue would be to change the response to:
#![allow(unused)] +fn main() { +enum BlobResponse { + Blob(Vec<u8>), + Blobs(MerkleTree), +} +}
With this the hash specified in the request can also be a merkle root and the +responder will respond with the entire merkle tree (only hashes, no payload). +Then the requester can traverse the leaf hashes and use the same request +response protocol to request any locally missing blobs in that tree.
One leaf would for example be the PVF others could be smart contracts. With a +properly specified format (e.g. which leaf is the PVF?), what we got here is +that a parachain can not only update its PVF, but additional data, +incrementally. E.g. adding another smart contract, does not require resubmitting +the entire PVF to validators, only the root hash on the relay chain gets +updated, then validators fetch the merkle tree and only fetch any missing +leaves. That additional data could be made available to the PVF via a to be +added host function. The nice thing about this approach is, that while we can +upgrade incrementally, lifetime is still tied to the PVF and we get all the same +guarantees. Assuming the validators store blobs by hash, we even get disk +sharing if multiple parachains use the same data (e.g. same smart contracts).
SetFeesMode
fees_mode
The SetFeesMode instruction and the fees_mode register allow for the existence of JIT withdrawal. +JIT withdrawal complicates the fee mechanism and leads to bugs and unexpected behaviour. +The proposal is to remove said functionality. +Another effort to simplify fee handling in XCM.
The JIT withdrawal mechanism creates bugs such as not being able to get fees when all assets are put into holding and none left in the origin location. +This is a confusing behavior, since there are funds for fees, just not where the XCVM wants them. +The XCVM should have only one entrypoint to fee payment, the holding register. +That way there is also less surface for bugs.
The SetFeesMode instruction will be removed. +The Fees Mode register will be removed.
Fees Mode
Users will have to make sure to put enough assets in WithdrawAsset when +previously some things might have been charged directly from their accounts. +This leads to a more predictable behaviour though so it will only be +a drawback for the minority of users.
WithdrawAsset
Implementations and benchmarking must change for most existing pallet calls +that send XCMs to other locations.
Performance will be improved since unnecessary checks will be avoided.
JIT withdrawal was a way of side-stepping the regular flow of XCM programs. +By removing it, the spec is simplified but now old use-cases have to work with +the original intended behaviour, which may result in more implementation work.
Ergonomics for users will undoubtedly improve since the system is more predictable.
Existing programs in the ecosystem will break. +The instruction should be deprecated as soon as this RFC is approved +(but still fully supported), then removed in a subsequent XCM version +(probably deprecate in v5, remove in v6).
The previous RFC PR on the xcm-format repo, before XCM RFCs were moved to fellowship RFCs: https://github.com/polkadot-fellows/xcm-format/pull/57.
The new generic fees mechanism is related to this proposal and further stimulates it as the JIT withdraw fees mechanism will become useless anyway.
This RFC proposes a solution to replicate an existing pure proxy from one chain to others. The aim is to address the current limitations where pure proxy accounts, which are keyless, cannot have their proxy relationships recreated on different chains. This leads to issues where funds or permissions transferred to the same keyless account address on chains other than its origin chain become inaccessible.
A pure proxy is a new account created by a primary account. The primary account is set as a proxy for the pure proxy account, managing it. Pure proxies are keyless and non-reproducible, meaning they lack a private key and have an address derived from a preimage determined by on-chain logic. More on pure proxies can be found here.
For the purpose of this document, we define a keyless account as a "pure account", the controlling account as a "proxy account", and the entire relationship as a "pure proxy".
The relationship between a pure account (e.g., account ID: pure1) and its proxy (e.g., account ID: alice) is stored on-chain (e.g., parachain A) and currently cannot be replicated to another chain (e.g., parachain B). Because the account pure1 is keyless and its proxy relationship with alice is not replicable from the parachain A to the parachain B, alice does not control the pure1 account on the parachain B.
pure1
alice
A
B
Although this behaviour is not promised, users and clients often mistakenly expect alice to control the same pure1 account on the parachain B. As a result, assets transferred to the account or permissions granted for it are inaccessible. Several factors contribute to this misuse:
Given that these mistakes are likely, it is necessary to provide a solution to either prevent them or enable access to a pure account on a target chain.
Runtime Users, Runtime Devs, wallets, cross-chain dApps.
One possible solution is to allow a proxy to create or replicate a pure proxy relationship for the same pure account on a target chain. For example, Alice, as the proxy of the pure1 pure account on parachain A, should be able to set a proxy for the same pure1 account on parachain B.
To minimise security risks, the parachain B should grant the parachain A the least amount of permission necessary for the replication. First, Parachain A claims to Parachain B that the operation is commanded by the pure account, and thus by its proxy, and second, provides proof that the account is keyless.
The replication process will be facilitated by XCM, with the first claim made using the DescendOrigin instruction. The replication call on parachain A would require a signed origin by the pure account and construct an XCM program for parachain B, where it first descends the origin, resulting in the ParachainA/AccountId32(pure1) origin location on the receiving side.
DescendOrigin
ParachainA/AccountId32(pure1)
To prove that the pure account is keyless, the client must provide the initial preimage used by the chain to derive the pure account. Parachain A verifies it and sends it to parachain B with the replication request.
We can draft a pallet extension for the proxy pallet, which needs to be initialised on both sides to enable replication:
#![allow(unused)] +fn main() { +// Simplified version to illustrate the concept. +mod pallet_proxy_replica { + /// The part of the pure account preimage that has to be provided by a client. + struct Witness { + /// Pure proxy swapner + spawner: AccountId, + /// Disambiguation index + index: u16, + /// The block height and extrinsic index of when the pure account was created. + block_number: BlockNumber, + /// The extrinsic index. + ext_index: u32, + // Part of the preimage, but constant. + // proxy_type: ProxyType::Any, + } + // ... + + /// The replication call to be initiated on the source chain. + // Simplified version, the XCM part will be abstracted by the `Config` trait. + fn replicate(origin: SignedOrigin, witness: Witness, proxy: xcm::Location) -> ... { + let pure = ensure_signed(origin); + ensure!(pure == proxy_pallet::derive_pure_account(witness), Error::NotPureAccount); + let xcm = vec![ + DescendOrigin(who), + Transact( + // … + origin_kind: OriginKind::Xcm, + call: pallet_proxy_replica::create(witness, proxy).encode(), + ) + ]; + xcmTransport::send(xcm)?; + } + // … + + /// The call initiated by the source chain on the receiving chain. + // `Config::CreateOrigin` - generally open for whitelisted parachain IDs and + // converts `Origin::Xcm(ParachainA/AccountId32(pure1))` to `AccountID(pure1)`. + fn create(origin: Config::CreateOrigin, witness: Witness, proxy: xcm::Location) -> ... { + let pure = T::CreateOrigin::ensure_origin(origin); + ensure!(pure == proxy_pallet::derive_pure_account(witness), Error::NotPureAccount); + proxy_pallet::create_pure_proxy(pure, proxy); + } +} + +}
There are two disadvantages to this approach:
We could eliminate the first disadvantage by allowing only the spawner of the pure proxy to recreate the pure proxies, if they sign the transaction on a remote chain and supply the witness/preimage. Since the preimage of a pure account includes the account ID of the spawner, we can verify that the account signing the transaction is indeed the spawner of the given pure account. However, this approach would grant exclusive rights to the spawner over the pure account, which is not a property of pure proxies at present. This is why it's not an option for us.
As an alternative to requiring clients to provide a witness data, we could label pure accounts on the source chain and trust it on the receiving chain. However, this would require the receiving chain to place greater trust in the source chain. If the source chain is compromised, any type of account on the trusting chain could also be compromised.
A conceptually different solution would be to not implement replication of pure proxies and instead inform users that ownership of a pure proxy on one chain does not imply ownership of the same account on another chain. This solution seems complex, as it would require UIs and clients to adapt to this understanding. Moreover, mistakes would likely remain unavoidable.
Each chain expressly authorizes another chain to replicate its pure proxies, accepting the inherent risk of that chain potentially being compromised. This authorization allows a malicious actor from the compromised chain to take control of any pure proxy account on the chain that granted the authorization. However, this is limited to pure proxies that originated from the compromised chain if they have a chain-specific seed within the preimage.
There is a security issue, not introduced by the proposed solution but worth mentioning. The same spawner can create the pure accounts on different chains controlled by the different accounts. This is possible because the current preimage version of the proxy pallet does not include any non-reproducible, chain-specific data, and elements like block numbers and extrinsic indexes can be reproduced with some effort. This issue could be addressed by adding a chain-specific seed into the preimages of pure accounts.
The replication is facilitated by XCM, which adds some additional load to the communication channel. However, since the number of replications is not expected to be large, the impact is minimal.
The proposed solution does not alter any existing interfaces. It does require clients to obtain the witness data which should not be an issue with support of an indexer.
This RFC proposes compressing the state response message during the state syncing process to reduce the amount of data transferred.
State syncing can require downloading several gigabytes of data, particularly for blockchains with large state sizes, such as Astar, which +has a state size exceeding 5 GiB (https://github.com/AstarNetwork/Astar/issues/1110). This presents a significant +challenge for nodes with slower network connections. Additionally, the current state sync implementation lacks a persistence feature (https://github.com/paritytech/polkadot-sdk/issues/4), +meaning any network disruption forces the node to re-download the entire state, making the process even more difficult.
This RFC benefits all projects utilizing the Substrate framework, specifically in improving the efficiency of state syncing.
The largest portion of the state response message consists of either CompactProof or Vec<KeyValueStateEntry>, depending on whether a proof is requested (source):
CompactProof
Vec<KeyValueStateEntry>
None identified.
The code changes required for this RFC are straightforward: compress the state response on the sender side and decompress it on the receiver side. Existing sync tests should ensure functionality remains intact.
This RFC optimizes network bandwidth usage during state syncing, particularly for blockchains with gigabyte-sized states, while introducing negligible CPU overhead for compression and decompression. For example, compressing the state response during a recent Polkadot warp sync (around height #22076653) reduces the data transferred from 530,310,121 bytes to 352,583,455 bytes — a 33% reduction, saving approximately 169 MiB of data.
Performance data is based on this patch, with logs available here.
No compatibility issues identified.
secp256r1_ecdsa_verify_prehashed
NIST-P256
This RFC proposes a new host function, secp256r1_ecdsa_verify_prehashed, for verifying NIST-P256 signatures. The function takes as input the message hash, r and s components of the signature, and the x and y coordinates of the public key. By providing this function, runtime authors can leverage a more efficient verification mechanism for "secp256r1" elliptic curve signatures, reducing computational costs and improving overall performance.
r
s
x
y
“secp256r1” elliptic curve is a standardized curve by NIST which has the same calculations by different input parameters with “secp256k1” elliptic curve. The cost of combined attacks and the security conditions are almost the same for both curves. Adding a host function can provide signature verifications using the “secp256r1” elliptic curve in the runtime and multi-faceted benefits can occur. One important factor is that this curve is widely used and supported in many modern devices such as Apple’s Secure Enclave, Webauthn, Android Keychain which proves the user adoption. Additionally, the introduction of this host function could enable valuable features in the account abstraction which allows more efficient and flexible management of accounts by transaction signs in mobile devices. +Most of the modern devices and applications rely on the “secp256r1” elliptic curve. The addition of this host function enables a more efficient verification of device native transaction signing mechanisms. For example:
This RFC proposes a new host function for runtime authors to leverage a more efficient verification mechanism for "secp256r1" elliptic curve signatures.
Proposed host function signature:
#![allow(unused)] +fn main() { +fn ext_secp256r1_ecdsa_verify_prehashed_version_1( + sig: &[u8; 64], + msg: &[u8; 32], + pub_key: &[u8; 64], +) -> bool; +}
The host function MUST return true if the signature is valid or false otherwise.
true
false
The changes are not directly affecting the protocol security, parachains are not enforced to use the host function.
The host function proposed in this RFC allows parachain runtime developers to use a more efficient verification mechanism for "secp256r1" elliptic curve signatures.
Parachain teams will need to include this host function to upgrade.
A followup of the RFC-0014. This RFC proposes adding a new collective to the Polkadot Collectives +Chain: The Unbrick Collective, as well as improvements in the mechanisms that will allow teams +operating paras that had stopped producing blocks to be assisted, in order to restore the production +of blocks of these paras.
Since the initial launch of Polkadot parachains, there has been many incidients causing parachains +to stop producing new blocks (therefore, being bricked) and many occurrences that required +Polkadot governance to update the parachain head state/wasm. This can be due to many reasons range +from incorrectly registering the initial head state, inability to use sudo key, bad runtime +migration, bad weight configuration, and bugs in the development of the Polkadot SDK.
Currently, when the para is not unlocked in the paras registrar1, the Root origin is required to +perform such actions, involving the governance process to invoke this origin, which can be very +resource expensive for the teams. The long voting and enactment times also could result significant +damage to the parachain and users.
Root
Finally, other instances of governance that might enact a call using the Root origin (like the +Polkadot Fellowship), due to the nature of their mission, are not fit to carry these kind of tasks.
In consequence, the idea of a Unbrick Collective that can provide assistance to para teams when +they brick and further protection against future halts is reasonable enough.
The Unbrick Collective is defined as an unranked collective of members, not paid by the Polkadot +Treasury. Its main goal is to serve as a point of contact and assistance for enacting the actions +needed to unbrick a para. Such actions are:
In order to ensure these changes are safe enough for the network, actions enacted by the Unbrick +Collective must be whitelisted via similar mechanisms followed by collectives like the Polkadot +Fellowship. This will prevent unintended, not overseen changes on other paras to occur.
Also, teams might opt-in to delegate handling their para in the registry to the Collective. This +allows to perform similar actions using the paras registrar, allowing for a shorter path to unbrick a +para.
Initially, the unbrick collective has powers similar to a parachains own sudo, but permits more +decentralized control. In the future, Polkadot shall provide functionality like SPREE or JAM that +exceeds sudo permissions, so the unbrick collective cannot modify those state roots or code.
flowchart TD + A[Start] + + A -- Bricked --> C[Request para unlock via Root] + C -- Approved --> Y + C -- Rejected --> A + + D[unbrick call proposal on WhitelistedUnbrickCaller] + E[whitelist call proposal on the Unbrick governance] + E -- call whitelisted --> F[unbrick call enacted] + D -- unbrick called --> F + F --> Y + + A -- Not bricked --> O[Opt-in to the Collective] + O -- Bricked --> D + O -- Bricked --> E + + Y[update PVF / head state] -- Unbricked --> Z[End] +
Initially, a para team has two paths to handle a potential unbrick of their para in the case it +stops producing blocks.
The collective will be initially created without members (no seeding). There will be additional +governance proposals to setup the seed members.
The origins able to modify the members of the collective are:
Fellows
The members are responsible to verify the technical details of the unbrick requests (i.e. the hash +of the new PVF being set). Therefore, they must have the technical capacity to perform such tasks.
Suggested requirements to become a member are the following:
The ability to modify the Head State and/or the PVF of a para means a possibility to perform +arbitrary modifications of it (i.e. take control the native parachain token or any bridged assets +in the para).
This could introduce a new attack vector, and therefore, such great power needs to be handled +carefully.
The implementation of this RFC will be tested on testnets (Rococo and Westend) first.
An audit will be required to ensure the implementation doesn't introduce unwanted side effects.
There are no privacy related concerns.
This RFC should improve the experience for new and existing parachain teams, lowering the barrier +to unbrick a stalled para.
This RFC is fully compatible with existing interfaces.
WhitelistedUnbrickCaller
Unbrick
The paras registrar refers to a pallet in the Relay, responsible to gather registration info +of the paras, the locked/unlocked state, and the manager info.
In an attempt to mitigate risks derived from unwanted behaviours around long decision periods on +referenda, this proposal describes how to finalize and decide a result of a poll via a +mechanism similar to candle auctions.
Referenda protocol provide permissionless and efficient mechanisms to enable governance actors to +decide the future of the blockchains around Polkadot network. However, they pose a series of risks +derived from the game theory perspective around these mechanisms. One of them being where an actor +uses the the public nature of the tally of a poll as a way of determining the best point in time to +alter a poll in a meaningful way.
While this behaviour is expected based on the current design of the referenda logic, given the +recent extension of ongoing times (up to 1 month), the incentives for a bad actor to cause losses +on a proposer, reflected as wasted cost of opportunity increase, and thus, this otherwise +reasonable outcome becomes an attack vector, a potential risk to mitigate, especially when such +attack can compromise critical guarantees of the protocol (such as its upgradeability).
To mitigate this, the referenda underlying mechanisms should incentive actors to cast their votes +on a poll as early as possible. This proposal's approach suggests using a Candle Auction that will +be determined right after the confirm period finishes, thus decreasing the chances of actors to +alter the results of a poll on confirming state, and instead incentivizing them to cast their votes +earlier, on deciding state.
Finalizing
Currently, the process of a referendum/poll is defined as an sequence between an ongoing state +(where accounts can vote), comprised by a with a preparation period, a decision period, and a +confirm period. If the poll is passing before the decision period ends, it's possible to push +forward to confirm period, and still, go back in case the poll fails. Once the decision period +ends, a failure of the poll in the confirm period will lead to the poll to ultimately be rejected.
stateDiagram-v2 + sb: Submission + pp: Preparation Period + dp: Decision Period + cp: Confirmation Period + state dpd <<choice>> + state ps <<choice>> + cf: Approved + rj: Rejected + + [*] --> sb + sb --> pp + pp --> dp: decision period starts + dp --> cp: poll is passing + dp --> ps: decision period ends + ps --> cp: poll is passing + cp --> dpd: poll fails + dpd --> dp: decision period not deadlined + ps --> rj: poll is failing + dpd --> rj: decision period deadlined + cp --> cf + cf --> [*] + rj --> [*] +
This specification proposes three changes to implement this candle mechanism:
This mechanism MUST be enabled via a configuration parameter. Once enabled, the referenda system +MAY record the next poll ID from which to start enabling this mechanism. This is to preserve +backwards compatibility with currently ongoing polls.
A record of the poll status (whether it is passing or not) is stored once the decision period is +finished.
Including a Finalization period as part of the ongoing state. From this point, the poll MUST +be immutable at this point.
This period begins the moment after confirm period ends, and extends the decision for a couple +of blocks, until the VRF seed used to determine the candle block can be considered +"good enough". This is, not known before the ongoing period (decision/confirmation) was over.
Once that happens, a random block within the confirm period is chosen, and the decision of +approving or rejecting the poll is based on the status immediately before the block where the +candle was "lit-off".
When enabled, the state diagram for the referenda system is the following:
stateDiagram-v2 + sb: Submission + pp: Preparation Period + dp: Decision Period + cp: Confirmation Period + cds: Finalization + state dpd <<choice>> + state ps <<choice>> + state cd <<choice>> + cf: Approved + rj: Rejected + + [*] --> sb + sb --> pp + pp --> dp: decision period starts + dp --> cp: poll is passing + ps --> cp: poll is passing + dp --> ps: decision period ends + ps --> rj: poll is failing + cp --> dpd: poll fails + dpd --> cp: decision period over + dpd --> dp: decision period not over + cp --> cds: confirmation period ends + cds --> cd: define moment when candle lit-off + cd --> cf: poll passed + cd --> rj: poll failed + cf --> [*] + rj --> [*] +
This approach doesn't include a mechanism to determine whether a change of the poll status in the +confirming period is due to a legitimate change of mind of the voters, or an exploitation of its +aforementioned vulnerabilities (like a sniping attack), instead treating all of them as potential +attacks.
This is an issue that can be addressed by additional mechanisms, and heuristics that can help +determine the probability of a change of poll status to happen as a result of a legitimate behaviour.
The implementation of this RFC will be tested on testnets (Paseo and Westend) first. Furthermore, it +should be enabled in a canary network (like Kusama) to ensure the behaviours it is trying to address +is indeed avoided.
The added steps imply pessimization, necessary to meet the expected changes. An implementation MUST +exit from the Finalization period as early as possible to minimize this impact.
This proposal does not alter the already exposed interfaces or developers or end users. However, they +must be aware of the changes in the additional overhead the new period might incur (these depend on the +implemented VRF).
This proposal does not break compatibility with existing interfaces, older versions, but it alters the +previous implementation of the referendum processing algorithm.
An acceptable upgrade strategy that can be applied is defining a point in time (block number, poll index) +from which to start applying the new mechanism, thus, not affecting the already ongoing referenda.
polkadot-runtime-commont
A proposed implementation of this change can be seen on this Pull Request.
This RFC proposes the definition of version 5 extrinsics along with changes to the specification and +encoding from version 4.
RFC84 +introduced the specification of General transactions, a new type of extrinsic besides the Signed +and Unsigned variants available previously in version 4. Additionally, +RFC99 +introduced versioning of transaction extensions through an extra byte in the extrinsic encoding. +Both of these changes require an extrinsic format version bump as both the semantics around +extensions as well as the actual encoding of extrinsics need to change to accommodate these new +features.
General
Signed
Unsigned
The introduction of General transactions allows the authorization of any and all origins through +extensions. This means that, with the appropriate extension, General transactions can replicate +the same behavior present-day v4 Signed transactions. Specifically for Polkadot chains, an example +implementation for such an extension is +VerifySignature, +introduced in the Transaction Extension +PR3685. Other extensions can be inserted +into the extension pipeline to authorize different custom origins. Therefore, a Signed extrinsic +variant is redundant to a General one strictly in terms of user functionality and could eventually +be deprecated and removed.
VerifySignature
As with version 4, the encoded extrinsic v5 is a SCALE encoded vector of bytes (u8), therefore +starting with the encoded length of the following bytes in compact format. The leading byte after +the length determines the version and type of extrinsic, as specified by +RFC84. +For reasons mentioned above, this RFC removes the Signed variant for v5 extrinsics.
u8
For Bare extrinsics, the following bytes will just be the encoded call and nothing else.
Bare
For General transactions, as stated in +RFC99, +an extension version byte must be added to the extrinsic format. This byte should allow runtimes to +expose more than one set of extensions which can be used for a transaction. As far as the v5 +extrinsic encoding is concerned, this extension byte should be encoded immediately after the leading +encoding byte. The extension version byte should be included in payloads to be signed by all +extensions configured by runtime devs to ensure a user's extension version choice cannot be altered +by third parties.
After the extension version byte, the extensions will be encoded next, followed by the call itself.
A quick visualization of the encoding:
(extrinsic_encoded_len, 0b0000_0101, call)
(extrinsic_encoded_len, , 0b0100_0101, extension_version_byte, extensions, call)
In order to run a transaction with a signed origin in extrinsic version 5, a user must create the +transaction with an instance of at least one extension responsible for authorizing Signed origins +with a provided signature.
As stated before, PR3685 comes with a +Transaction Extension which replicates the current Signed transactions in v5 extrinsics, namely +VerifySignature. +I will use this extension as an example on how to replicate current Signed transaction +functionality in the new v5 extrinsic format, though the runtime logic is not constrained to this +particular implementation.
This extension leverages the new inherited implication functionality introduced in +TransactionExtension and creates a payload to be signed using the data of all extensions after +itself in the extension pipeline. This extension can be configured to accept a MultiSignature, +which makes it compatible with all signature types currently used in Polkadot.
TransactionExtension
MultiSignature
In the context of using an extension such as VerifySignature, for example, to replicate current +Signed transaction functionality, the steps to generate the payload to be signed would be:
BLAKE2_256
#![allow(unused)] +fn main() { +// Step 1: encode the bytes +let encoded = (extension_version_byte, call, transaction_extension, transaction_extension_implicit).encode(); +// Step 2: hash them +let payload = blake2_256(&encoded[..]); +// Step 3: sign the payload +let signature = keyring.sign(&payload[..]); +}
In order to minimize the number of changes to the extrinsic format version and also to help all +consumers downstream in the transition period between these extrinsic versions, we should:
The metadata will have to accommodate two distinct extrinsic format versions at a given point in +time in order to provide the new functionality in a non-breaking way for users and tooling.
Although having to support multiple extrinsic versions in metadata involves extra work, the change +is ultimately an improvement to metadata and the extra functionality may be useful in other future +scenarios.
There is no impact on testing, security or privacy.
This change makes the authorization through signatures configurable by runtime devs in version 5 +extrinsics, as opposed to version 4 where the signing payload algorithm and signatures were +hardcoded. This moves the responsibility of ensuring proper authentication through +TransactionExtension to the runtime devs, but a sensible default which closely resembles the +present day behavior will be provided in VerifySignature.
There is no performance impact.
Tooling will have to adapt to be able to tell which authorization scheme is used by a particular +transaction by decoding the extension and checking which particular TransactionExtension in the +pipeline is enabled to do the origin authorization. Previously, this was done by simply checking +whether the transaction is signed or unsigned, as there was only one method of authentication.
As long as extrinsic version 4 is still exposed in the metadata when version 5 will be introduced, +the changes will not break existing infrastructure. This should give enough time for tooling to +support version 5 and to remove version 4 in the future.
This is a result of the work in Extrinsic +Horizon and +RFC99.
Following this change, extrinsic version 5 will be introduced as part of the Extrinsic +Horizon effort, which will shape future +work.
The current election mechanism for permissionless collators on system chains was introduced in +RFC-7. +This RFC proposes a mechanism to facilitate replacements in the invulnerable sets of system chains +by breaking down barriers that exist today.
Following RFC-7 and the introduction of the collator election +mechanism, anyone can now collate on a system +chain on the permissionless slots, but the invulnerable set has been a contentious issue among +current collators on system chains as the path towards an invulnerable slot is almost impossible to +pursue. From a technical standpoint, nothing is preventing a permissionless collator, or anyone for +that matter, from submitting a referendum to remove one collator from the invulnerable set and add +themselves in their place. However, as it quickly becomes obvious, such a referendum would be very +difficult to pass under normal circumstances.
The first reason this would be contentious is that there is no significant difference between +collators with good performance. There is no reasonable way to keep track of arbitrary data on-chain +which could clearly and consistently distinguish between one collator or another. Collators that +perform well propose blocks when they are supposed to and that is what is being tracked on-chain. +Any other metrics for performance are arbitrary as far as the runtime logic is concerned and should +be reasoned upon by humans using public discussion and a referendum.
The second reason for this is the inherently social aspect of this action. Even just proposing the +referendum would be perceived as an attack on a specific collator in the set, singling them out, +when in reality the proposer likely just wants to be part of the set and doesn't necessarily care +who is kicked. In order to consolidate their position, the other invulnerables will rally behind the +one that was challenged and the bid to replace one invulnerable will probably fail.
Existing invulnerables have a vested interest in protecting any other invulnerable from such attacks +so that they themselves would be protected if need be. The existing collator set has already +demonstrated that they can work together and subvert the free market mechanism offered by the +runtime when they agreed to not outbid each other on permissionless slots after the new collator +selection mechanism was introduced.
The existing invulnerable set on a given system chain are there for a reason; they have demonstrated +reliability in the past and were rewarded by governance with invulnerable slots and a bounty to +cover their expenses. This means they have a solid reputation and a strong say in governance over +matters related to collation. The optics of a permissionless collator actively challenging an +invulnerable, even when it's justified, combined with the support of other invulnerables, make the +invulnerable set de facto immutable.
While there should be strong guarantees of stability for invulnerables, they should not be a closed +circle. The aim of this RFC is to provide a clear, reasonable, fair, and socially acceptable path +for a permissionless collator with a proven track record to become an invulnerable while preserving +the stability of the invulnerable set of a system parachain.
This RFC proposes a periodic, mandatory, round-robin, two-round election mechanism for +invulnerables.
The election should be implemented on top of the current logic in the collator-selection pallet. +In this mechanism, candidates would register for the first round of the next election by placing +deposits.
collator-selection
When the period between elections passes, the first round of the election starts with every +candidate that registered, excluding the incumbent, as an option on the ballot. Votes should be +expressed using tokens which should not be available for other transactions while the election is +ongoing in order to introduce some opportunity cost to voting. After a certain amount of time +passes, the election closes and the candidate who wins the first round of the election advances to +the second and final round of the election. The deposits held for voting in the first round must be +released before the second round.
In the second round of the election, the winner of the first round has the chance to replace the +invulnerable currently holding the slot. A referendum is submitted to replace the incumbent with the +winner of the first round of the election, turning the second round of the election into a +conviction-voting compatible referendum. If the referendum fails, the incumbent keeps their slot.
conviction-voting
The period between elections should be configurable at the collator-selection pallet level. A full +election cycle ends when the pallet held an election for every single invulnerable slot. To qualify +for the ballot, candidates must have been collating for at least one period from a permissionless +slot or be the incumbent.
MinEligibleCollators
The first major drawback of this proposal is that it would put more responsibility on governance by +having people vote regularly in order to maintain the invulnerable collator set on each chain. Today +the collator-selection pallet employs a fire-and-forget system where the invulnerables are chosen +once by governance vote. Although in theory governance can always intervene to elect new +invulnerables, for the reasons stated in this RFC this is not the case in practice. Moving away from +this system means more action is needed from governance to ensure the stability of the invulnerable +collator sets on each system chain, which automatically increases the probability of errors. +However, governance is the ultimate source of truth on-chain and there is a lot more at stake in the +hands of governance than the invulnerable collator sets on system chains, so I think this risk is +acceptable.
The second drawback of this proposal is the imperfect voting mechanism. Probably the simplest and +most fair voting system for this scenario would have been First Past the Post, where all candidates +participate in a single election round and the candidate with the most votes wins the election +outright. However, the downside of such a system is the technical complexity behind running such an +election on-chain. This election mechanism would require a multiple choice referendum implementation +in the collator-selection pallet or at the system level somewhere else (e.g. on the Collectives +chain), which would be a mix between the conviction-voting and staking pallets and would +possibly communicate with all system chains via XCM. While this voting system could be useful in +other contexts as well, I don't think it's worth conditioning the invulnerable collator redesign on +a separate implementation of the multiple choice voting system when the Two-Round proposed achieves +the objectives of this RFC.
staking
All election mechanisms as well as corner cases can be covered with unit tests.
The chain will have to run extrinsics to start and end elections periodically, but the impact in +terms of weight and PoV size is negligible.
The invulnerables will be the most affected group, as they will have to now compete in elections +periodically to secure their spots. Permissionless candidates will now have a clear, though not +guaranteed, path towards becoming an invulnerable, at least for a period of time.
Any changes to the election mechanism of invulnerables should be compatible with the current +invulnerable set interaction with the collator set chosen at the session boundary. The current +invulnerable set for each chain can be grandfathered in when upgrading the collator-selection +pallet version.
This RFC builds on RFC-7, which introduced the election mechanism for system chain collators.
The main spinoff of this RFC might be a multiple choice poll implementation in a separate pallet to +hold a First Past the Post election instead of the Two-Round System proposed, which would prompt a +migration to the new voting system within the collator-selection pallet. Additionally, a more +complex solution where the voting for all system chains happens in a single place which then sends +XCM responses with election results back to system chains can be implemented in the next iteration +of this RFC.
Update the runtime-host interface so that it no longer uses the host-side allocator.
The API of these new functions was heavily inspired by the API used by the C programming language.
This RFC is mainly based on RFC-4 by @tomaka, which was never adopted, and this RFC supersedes it.
ext_misc_runtime_version
ext_offchain_random_seed
The API of many host functions contains buffer allocations. For example, when calling ext_hashing_twox_256_version_1, the host allocates a 32-byte buffer using the host allocator, and returns a pointer to this buffer to the runtime. The runtime later has to call ext_allocator_free_version_1 on this pointer to free the buffer.
Even though no benchmark has been done, it is pretty obvious that this design is very inefficient. To continue with the example of ext_hashing_twox_256_version_1, it would be more efficient to instead write the output hash to a buffer allocated by the runtime on its stack and passed by pointer to the function. Allocating a buffer on the stack, in the worst case, consists simply of decreasing a number; in the best case, it is free. Doing so would save many VM memory reads and writes by the allocator, and would save a function call to ext_allocator_free_version_1.
Furthermore, the existence of the host-side allocator has become questionable over time. It is implemented in a very naive way, and for determinism and backwards compatibility reasons, it needs to be implemented exactly identically in every client implementation. Runtimes make substantial use of heap memory allocations, and each allocation needs to go through the runtime <-> host boundary twice (once for allocating and once for freeing). Moving the allocator to the runtime side would be a good idea, although it would increase the runtime size. But before the host-side allocator can be deprecated, all the host functions that use it must be updated to avoid using it.
No attempt was made to convince stakeholders.
The Runtime optional positive integer is a signed 64-bit value. Positive values in the range of [0..2³²) represent corresponding unsigned 32-bit values. The value of -1 represents a non-existing value (an absent value). All other values are invalid.
Currently, all runtime entrypoints have the following identical Wasm function signatures:
(func $runtime_entrypoint (param $data i32) (param $len i32) (result i64))
This RFC proposes changes to pallet-conviction-voting that allow for simultaneous voting and delegation. For example, Alice could delegate to Bob, then later vote on a referendum while keeping their delegation to Bob intact. It is a strict subset of Leemo's RFC 35.
pallet-conviction-voting
Under our current voting system, a voter can either vote or delegate. To vote, they must first ensure they have no delegate, and to delegate, they must first clear their current votes.
This RFC aims to solve the second and third issue and thus more accurately align governance to the true voter preferences.
One may ask, could a voter not just undelegate, vote, then delegate again? Could this just be built into the user interface? Unfortunately, this does not work due to the need to clear their votes before redelegation. In practice the voter would undelegate, vote, wait until the referendum is closed, hope that there's no other referenda they would like to vote on, then redelegate. At best it's a temporally extended friction. At worst the voter goes unrepresented in voting for the duration of the vote clearing period.
Runtime developers: If runtime developers are relying on the previous assumptions for their VotingHooks implementations, they will need to rethink their approach. In addition, a runtime migration is needed. Lastly, it is a serious change in governance that requires some consideration beyond the technical.
Runtime developers
App developers: Apps like Subsquare and Polkassembly would need to update their user interface logic. They will also need to handle the new error.
App developers
Users: We will want users to be aware of the new functionality, though not required.
Users
Technical Writers: This change will require rewrites of documentation and tutorials.
Technical Writers
The Voting Enum, which currently holds the user's vote data, would first be collapsed and it's underlying fields consolidated, as there would no longer be a distinction between the enum's variants. A (poll index -> retracted votes count) field would then be added to the resulting structure - It's role to keep track of the per poll balance that has been clawed back from the user by those delegating to them. See here for a potential implementation.
(poll index -> retracted votes count)
The implementation must allow for the (poll index -> retracted votes) data to exist even if the user does not currently have a vote for that poll. A simple example that highlights the necessity is as follows: A delegator votes first, then the delegate does. If the delegator is not allowed to create the retracted votes data on the delegate, the tally count would be corrupted when the delegate votes.
(poll index -> retracted votes)
A user's locked balance will be the greater of the delegation lock and the voting lock.
A runtime migration is necessary, though simple considering voting and delegation are currently separate. It would iterate over the VotingFor storage item and convert the old vote data structure to the new structure.
There are two potential drawbacks to this system -
If implemented, there will be no friction in delegating, undelegating, and voting. Therefore, there could be large and immediate shifts in the voter preferences function. In other voting systems we see bounds added to the rate of change (voting cycles, etc). That said, it is unclear whether this is desired or advantageous. Additionally, there are more easily parameterized and analytically tractable ways to handle this than what we currently have. See future directions.
If a delegate's voting power can be stripped from them at any point, then there is necessarily a reduction in their power within the system. This provides less incentive to become a delegate. But again, there are more customizable ways to handle this if it proves necessary.
This change would mean a more complicated STF for voting, which would increase difficulty of hardening. Though sufficient unit testing should handle this with ease.
The proposed changes would increase both the compute and storage requirements by about 2x for all voting functions. No change in complexity.
Voting and delegation will both become more ergonomic for users, as there are no longer hard constraints affecting what you can do and when you can do it.
Runtime developers will need to add the migration and ensure their hooks still work.
App developers will need to update their user interfaces to accommodate the new functionality. They will need to handle the new error as well.
A current implementation can be found here.
It is possible we would like to add a system parameter for the rate of change of the voting/delegation system. This could prevent wild swings in the voter preferences function and motivate/shield delegates by solidifying their positions over some amount of time. However, it's unclear that this would be valuable or even desirable.
This RFC proposes a decentralized market mechanism for allocating Coretime on Polkadot, replacing the existing Dutch auction method (RFC17). The proposed model leverages convex preference interactions among agents, eliminating explicit bidding and centralized price determination. This ensures fairness, transparency, and decentralization.
The current auction-based model (RFC17) presents critical issues:
Front-running and timing asymmetry: Actors with superior infrastructure or timing strategies possess unfair advantages.
Complexity and cognitive overhead: Auctions pose challenges for participant comprehension and effective engagement.
Resource hoarding and inefficiency: Auctions allow strategic actors to monopolize resources, restricting equitable participation.
The decentralized convex-preference model addresses these issues by facilitating asynchronous, equitable and transparent access before state coordination and deterministic verifiability during and after protocol consensus.
Primary set of stakeholders are:
Agents participating in the Coretime market (such as parachains, parathreads, or smart contracts) declare two parameters:
Asset Holdings: Their initial allocation of Coretime and tokens (e.g., DOT).
Preference Parameter (α): A scalar value between 0 and 1 indicating their valuation preference between Coretime and tokens.
These parameters are recorded transparently on-chain. Transactions between agents are conducted through deterministic convex optimizations, ensuring local Pareto-optimal exchanges. A global equilibrium price naturally emerges from these local interactions without any centralized authority or external pricing mechanism Tristain, 2024.
Agents' preferences are represented using a Cobb-Douglas utility function:
$U_i(x, y) = x^{α_i} y^{1-α_i}$
where:
Implementation involves the following components:
Preference & Asset Declaration → Paired-exchange Convex Optimization → Interaction Ordering (High-to-Low Exchange Impact) → Global Price Convergence → On-chain Auditability +
The implementation of this decentralized convex-preference Coretime market mechanism demands particular care in maintaining determinism, accuracy, and security in all on-chain interactions. Key considerations include:
The proposed mechanism relies on convex optimization over continuous variables, which REQUIRES floating-point arithmetic or high-precision fixed-point alternatives.
To ensure deterministic behavior across all nodes, arithmetic operations MUST be implemented using deterministic libraries or Wasm-compatible fixed-point math, avoiding non-deterministic floating-point behavior across architectures.
Verifiability of Pareto-optimal outcomes across interactions MUST be reproducible and provable, potentially leveraging range-limited arithmetic or bounded rational approximations for optimization solvers.
Preference declarations and asset holdings MUST be immutably recorded on-chain, subject to strict validation and input constraints to prevent manipulation.
The optimization process MUST prevent overflow, underflow, or division-by-zero attacks in edge-case preference combinations (e.g., α close to 0 or 1).
Any deterministic interaction ordering logic MUST be auditable and resistant to manipulation or reordering incentives by privileged actors.
Although the model emphasizes transparency and verifiability, it MAY be beneficial in future iterations to support privacy-preserving preference commitment schemes (e.g., via homomorphic encryption or zero-knowledge commitments).
This MAY allow agents to express preferences without revealing them publicly, while still enabling fair participation and on-chain verification.
Simulation of multiple interacting agents with heterogeneous preferences and randomized initial allocations SHOULD be used to validate global convergence and equilibrium behavior.
Fuzz testing and symbolic execution SHOULD be applied to the interaction module to identify corner cases in the optimization pipeline.
Formal verification of convergence routines and boundedness of the optimization space is RECOMMENDED for high-assurance deployments.
This leads to a more fluid, computation-bound system where efficiency stems from algorithmic design and verification speed, not from externally imposed timing constraints. Compatibility with existing Substrate pallets can be explored through modular implementation.
The system's performance depends on the availability of computational resources, not on arbitrary time windows or rounds. Price discovery and convergence are calculated as fast as the system can process the deterministic interaction rules. Pair-wise interactions can be batched and accumulated asynchronously. This enhances real-time responsiveness while removing artificial scheduling constraints.
Agents only need to express a simple scalar preference and their token/Coretime holdings, removing cognitive complexity. This lightweight interaction model improves usability, especially for smaller participants.
The mechanism is fully compatible with asynchronous execution architectures. Because it relies on deterministic local state transitions, it integrates seamlessly with Byzantine fault-tolerant consensus protocols and supports scalable, decentralized implementations.
RFC-1
Initial Forum Discussion (superseded) : Invitation to Critically Evaluate Core Time Pricing Model Framework
RFC Draft Proposal Preliminary Forum Thread: RFC: Decentralized Convex-Preference Coretime Market for Polkadot Draft
"Emergent Properties of Distributed Agents with Two-Stage Convex Zero-Sum Optimal Exchange Network": Tristain, 2024
Personally, I want to express a special gratitude to Edmundo Beteta for introduccing me to Microeconomics Theory and guiding my curiosity at the Faculty of Economics and Administration, Universidad de Chile.
Optimal method for initial rollout (experimental sandbox vs. partial deployment on Polkadot).
OPTIONAL criteria and heuristics for deterministic interaction ordering.
Extend the model to support multi-asset allocations with additional priority mechanisms.
Apply similar decentralized convex-preference principles to broader decentralized resource allocation challenges (e.g. JAM, energy/resource coordination, price stabilization).
This RFC proposes a modification to the AURA round-robin block production mechanism for system parachains (e.g. Polkadot Hub). The proposed change increases the number of consecutive block production slots assigned to each collator from the current single-slot allocation to a configurable value, initially set at four. This modification aims to enhance censorship resistance by mitigating data-withholding attacks.
The Polkadot Relay Chain guarantees the safety of parachain blocks, but it does not provide explicit guarantees for liveness or censorship resistance. With the planned migration of core Relay Chain functionalities—such as Balances, Staking, and Governance—to the Polkadot Hub system parachain in early November 2025, it becomes critical to establish a mechanism for achieving censorship resistance for these parachains without compromising throughput. For example, if governance functionality is migrated to Polkadot-Hub, malicious collators could systematically censor aye votes for a Relay Chain runtime upgrade, potentially altering the referendum's outcome. This demonstrates that censorship attacks on a system parachain can have a direct and undesirable impact on the security of the Relay Chain. This proposal addresses such censorship vulnerabilities by modifying the AURA block production mechanism utilized by system parachain collator with minimal honesty assumptions on the collators.
aye
where $m$ is the max_candidate_depth (or unincluded segment as seen from collator's perpective).
max_candidate_depth
Assuming the previous block data can be fetched from backers, then we comfortably have $a+b \leq 6s$, i.e. block buiding plus recoinstruciton time is < 6s. Using the current asyncdelay of 18s, suffices to set $x$ to 4. If the max_candidate_depth (m) for Polkadot Hub is set $m\leq3$, then this will reduce (improve) $x$ from 4 to $m$. Note that a channel would have to be provided for collators to fetch blocks from backers as the preferred option and only recover from availability layer as the fail-safe option.
asyncdelay
The proposed changes are security critical and mitigate censorship attacks on core functionality like balances, staking and governance on Polkadot Hub. This approach is compatible with the Slot-Based collation and the currently deployed FixedVelocityConsensusHook. Further analysis is needed to integrate with cusotm ConsesnsusHooks that leverage Elastic Scaling.
Multi-slot collation however is vulnerable to liveness attacks: adversarial collators don't show up to stall the liveness but then also lose out on block production rewards. The amount of missed blocks because of collators skipping is same as in the current implementation, only the distribution of missed slots changes (they are chunked together instead of being evenly distributed). Secondly, when ratio of adversarial (censoring) collators $\alpha$ is high (close to 1), the ratio of uncensored block to all blocks produced drops to $(1-\alpha)/(x\alpha)$. For more practical lower values of $\alpha<1/4$, the ratio of uncensored to all blocks is almost 1.
Effective multi-slot collation requires that collators be able to prioritize transactions that have been targeted for censorship. The implementation should incorporate a framework for priority transactions (e.g., governance votes, election extrinsics) to ensure that such transactions are included in the uncensored blocks.
This RFC is related to RFC-7, which details the selection mechanism for System Parachain Collators. In general, a more robust collator selection mechanism that reduces the proportion of malicious actors would directly benefit the effectiveness of the ideas presented in this RFC
A resilient mechanism is needed for prioritising transactions in block production for collators that are actively targeted for censorship. There are two potential approches:
+"Polkadot Hub should have a native DOT backed stable coin because people need it and otherwise we will haemorrhage benefits, liquidity and/or security." - Gav +
This RFC proposes to change the duration of the Confirmation Period for the Big Tipper and Small Tipper tracks in Polkadot OpenGov:
Small Tipper: 10 Minutes -> 12 Hours
Big Tipper: 1 Hour -> 1 Day
Currently, these are the durations of treasury tracks in Polkadot OpenGov. Confirmation periods for the Spender tracks were adjusted based on RFC20 and its related conversation.
You can see that there is a general trend on the Spender track that when the privilege level (the amount the track can spend) the confirmation period approximately doubles.
I believe that the Big Tipper and Small Tipper track's confirmation periods should be adjusted to match this trend.
In the current state it is possible to somewhat positively snipe these tracks, and whilst the power/privilege level of these tracks is very low (they cannot spend a large amount of funds), I believe we should increase the confirmation periods to something higher. This is backed up by the recent sentiment in the greater community regarding referendums submitted on these tracks. The parameters of Polkadot OpenGov can be adjusted based on the general sentiment of token holders when necessary.
The primary stakeholders of this RFC are: +– DOT token holders – as this affects the protocol's treasury +– Entities wishing to submit a referendum on these tracks – as this affects the referendum's timeline +– Projects with governance app integrations – see Performance, Ergonomics and Compatibility section below
This RFC proposes to change the duration of the confirmation period for both the Big Tipper and Small Tipper tracks. To achieve this the confirm_period parameter for those tracks should be changed.
confirm_period
You can see the lines of code that need to be adjusted here:
Big Tipper: https://github.com/polkadot-fellows/runtimes/blob/f4c5d272d4672387771fb038ef52ca36f3429096/relay/polkadot/src/governance/tracks.rs#L245
Small Tipper: https://github.com/polkadot-fellows/runtimes/blob/f4c5d272d4672387771fb038ef52ca36f3429096/relay/polkadot/src/governance/tracks.rs#L231
This RFC proposes to change the confirm_period for the Big Tipper track to DAYS (i.e. 1 Day) and the confirm_period for the Small Tipper track to 12 * HOURS (i.e. 12 Hours).
DAYS
12 * HOURS
The drawback of changing these confirmation periods is that the lifecycle of referenda submitted on those tracks would be ultimately longer, and it would add a greater potential to negatively "snipe" referenda on those tracks by knocking the referendum out of its confirmation period once the decision period has ended. This can be a good or a bad thing depending on your outlook of positive vs negative sniping.
This referendum will enhance the security of the protocol as it relates to its treasury. The confirmation period is one of the last lines of defense for the Polkadot token holder DAO to react to a potentially bad referendum and vote NAY in order for its confirmation period to be aborted.
This is a simple change (code wise) that should not affect the performance of the Polkadot protocol, outside of increasing the duration of the confirmation periods for these 2 tracks.
As per the implementation of changes described in RFC-20, it was identified that governance UIs automatically update to meet the new parameters:
Some token holders may want these confirmation periods to remain as they are currently and for them not to increase. If this is something that the Polkadot Technical Fellowship considers to be an issue to implement into a runtime upgrade then I can create a Wish For Change to obtain token holder approval.
The parameters of Polkadot OpenGov will likely continue to change over time, there are additional discussions in the community regarding adjusting the min_support for some tracks so that it does not trend towards 0%, similar to the current state of the Whitelisted Caller track. This is outside of the scope of this RFC and requires a lot more discussion.
min_support
This is a proposal to reduce the impact of stale nominations in the Polkadot staking system. With this proposal, nominators are incentivized to update or renew their selected validators once per time period. Nominators that do not update or renew their selected validators would be considered stale, and a decaying multiplier would be applied to their nominations, reducing the weight of their nomination and rewards.
Longer motivation behind the content of the RFC, presented as a combination of both problems and requirements for the solution.
One of Polkadot's primary utilities is providing a high quality security layer for applications built on top of it. To achieve this, Polkadot runs a Nominated Proof-of-Stake system, allowing nominators to vote on who they think are the best validators for Polkadot.
This system functions best when nominators and validators are active participants in the network. Nominators should consistently evaluate the quality and preferences of validators, and adjust their nominations accordingly.
Unfortunately, many Polkadot nominators do not play an active role in the NPoS system. For many, they set their nominations, and then seldomly look back at the.
This can lead to many negative behaviors:
Primary stakeholders are:
Detail-heavy explanation of the RFC, suitable for explanation to an implementer of the changeset. This should address corner cases in detail and provide justification behind decisions, and provide rationale for how the design meets the solution requirements.
Description of recognized drawbacks to the approach given in the RFC. Non-exhaustively, drawbacks relating to performance, ergonomics, user experience, security, or privacy.
Describe the the impact of the proposal on these three high-importance areas - how implementations can be tested for adherence, effects that the proposal has on security and privacy per-se, as well as any possible implementation pitfalls which should be clearly avoided.
Describe the impact of the proposal on the exposed functionality of Polkadot.
Is this an optimization or a necessary pessimization? What steps have been taken to minimize additional overhead?
If the proposal alters exposed interfaces to developers or end-users, which types of usage patterns have been optimized for?
Does this proposal break compatibility with existing interfaces, older versions of implementations? Summarize necessary migrations or upgrade strategies, if any.
Provide references to either prior art or other relevant research for the submitted design.
Provide specific questions to discuss and address before the RFC is voted on by the Fellowship. This should include, for example, alternatives to aspects of the proposed design where the appropriate trade-off to make is unclear.
Describe future work which could be enabled by this RFC, if it were accepted, as well as related RFCs. This is a place to brain-dump and explore possibilities, which themselves may become their own RFCs.
SessionKeys
This RFC is an amendment to RFC-0048. It proposes changing the OpaqueKeysInner:create_ownership_proof and OpaqueKeys:: ownership_proof_is_valid to invoke generation and validation procedures specific to each crypto type. This enables different crypto schemes to implement proof of possession that fits their security needs. In short, this RFC delegates the procedure of generating and validating proof of possession to the crypto schemes rather than dictating a uniform generation and verification.
Following RFC-0048, all submitted keys accompany a signature of the account_id by the same key, proving that the submitter knows the private key corresponding to the submitted key. However, a scheme should mandate a context-specific approach for generating proof of possession and a different context for signing anything else to prevent rogue key attacks [3]. While this is critical for schemes with aggregatable public keys, the other (non-aggregatable) crypto schemes opt for backward compatibility and accept signatures not prepended with mandatory context.
However, the current RFC does not allow using different API calls and procedures to generate proof of possession for different crypto schemes.
After this RFC, the procedure for generating and verifying proof of possession would be at the discretion of the crypto scheme itself, not deterministically tied to the way they sign other messages. Stakeholders
The RFC does not change the structure introduced by RFC-0048. The proof is a sequence of signatures:
#![allow(unused)] +fn main() { +type Proof = (Signature, Signature, ..); +}
However, each signature is generated by the crypto scheme instead of each private session key signing the account_id. By default, the following statement is signed by the crypto scheme:
account_id
rust +"POP_"|account_id +
The prefix could alert signers if they are misled into signing false proof of possession statements. More importantly, a new crypto scheme could specify a different structure for its proof of possession.
Because RFC-0048 has not been deployed, the version of the SessionKeys could still be set to 1 as requested by RFC-0048.
Crypto scheme needs to implement an explicit generate_proof_of_possession and verify_proof_of_possession runtime API in addition to old capabilities (sigen, verify, etc).
generate_proof_of_possession
verify_proof_of_possession
sigen
verify
The proof of possession for current crypto schemes is virtually identical to the one defined in RFC-0048. On the other hand, the changes proposed by this RFC allow the generation of secure proof of possession for BLS keys.
The performance is the same as the one discussed in RFC-0048.
Separating the generation of proof of possession from signing allows a crypto scheme more freedom to implement proof of possession that is fitted to its needs.
The significant difference is that proof of possession suggested by RFC-0048 is signed:
rust +account_id +
vs the current proposal suggests changing the statement to:
for the current crypto scheme. However, future crypto schemes such as BLS, which are not bound to backward compatibility, could produce more sophisticated proof of possession.
This is a minor amendment to RFC-0048.
- [1] Substrate implementation of the generation of proof of possession for all crypto schemes (current and experimental ones) is implemented in Pull 6010.
- [2] Substrate implementation of RFC-0048, in which the implementation of OpaqueKeysInner:create_ownership_proof and OpaqueKeys:: ownership_proof_is_valid should be modified to call generate_proof_of_possion and verify_proof_of_possession runtime APIs instead of directly calling the sign.
OpaqueKeysInner:create_ownership_proof
OpaqueKeys:: ownership_proof_is_valid
generate_proof_of_possion
- [3] Ristenpart, T., & Yilek, S. (2007). The power of proofs-of-possession: Securing multiparty signatures against rogue-key attacks. In , Annual {{International Conference}} on the {{Theory}} and {{Applications}} of {{Cryptographic Techniques} (pp. 228–245). : Springer).
This proposes a periodic, sale-based method for assigning Polkadot Coretime, the analogue of "block space" within the Polkadot Network. The method takes into account the need for long-term capital expenditure planning for teams building on Polkadot, yet also provides a means to allow Polkadot to capture long-term value in the resource which it sells. It supports the possibility of building rich and dynamic secondary markets to optimize resource allocation and largely avoids the need for parameterization.
The Polkadot Ubiquitous Computer, or just Polkadot UC, represents the public service provided by the Polkadot Network. It is a trust-free, WebAssembly-based, multicore, internet-native omnipresent virtual machine which is highly resilient to interference and corruption.
The present system of allocating the limited resources of the Polkadot Ubiquitous Computer is through a process known as parachain slot auctions. This is a parachain-centric paradigm whereby a single core is long-term allocated to a single parachain which itself implies a Substrate/Cumulus-based chain secured and connected via the Relay-chain. Slot auctions are on-chain candle auctions which proceed for several days and result in the core being assigned to the parachain for six months at a time up to 24 months in advance. Practically speaking, we only see two year periods being bid upon and leased.
More specifically, it is impossible to lease out cores at anything less than six months, and apparently unrealistic to do so at anything less than two years. This removes the ability to dynamically manage the underlying resource, and generally experimentation, iteration and innovation suffer. It bakes into the platform an assumption of permanence for anything deployed into it and restricts the market's ability to find a more optimal allocation of the finite resource.
There is no ability to determine capital requirements for hosting a parachain beyond two years from the point of its initial deployment onto Polkadot. While it would be unreasonable to have perfect and indefinite cost predictions for any real-world platform, not having any clarity whatsoever beyond "market rates" two years hence can be a very off-putting prospect for teams to buy into.
However, quite possibly the most substantial problem is both a perceived and often real high barrier to entry of the Polkadot ecosystem. By forcing innovators to either raise seven-figure sums through investors or appeal to the wider token-holding community, Polkadot makes it difficult for a small band of innovators to deploy their technology into Polkadot. While not being actually permissioned, it is also far from the barrierless, permissionless ideal which an innovation platform such as Polkadot should be striving for.
Furthermore, the design SHOULD be implementable and deployable in a timely fashion; three months from the acceptance of this RFC should not be unreasonable.
Primary stakeholder sets are:
Socialization:
The essensials of this proposal were presented at Polkadot Decoded 2023 Copenhagen on the Main Stage. A small amount of socialization at the Parachain Summit preceeded it and some substantial discussion followed it. Parity Ecosystem team is currently soliciting views from ecosystem teams who would be key stakeholders.
Upon implementation of this proposal, the parachain-centric slot auctions and associated crowdloans cease. Instead, Coretime on the Polkadot UC is sold by the Polkadot System in two separate formats: Bulk Coretime and Instantaneous Coretime.
When a Polkadot Core is utilized, we say it is dedicated to a Task rather than a "parachain". The Task to which a Core is dedicated may change at every Relay-chain block and while one predominant type of Task is to secure a Cumulus-based blockchain (i.e. a parachain), other types of Tasks are envisioned.
Bulk Coretime is sold periodically on a specialised system chain known as the Coretime-chain and allocated in advance of its usage, whereas Instantaneous Coretime is sold on the Relay-chain immediately prior to usage on a block-by-block basis.
The specific interface is properly described in RFC-5.
This proposal includes a number of parameters which need not necessarily be fixed. Their usage is explained below, but their values are suggested or specified in the later section Parameter Values.
The Coretime-chain includes some governance-set reservations of Coretime; these cover every System-chain. Additionally, governance is expected to initialize details of the pre-existing leased chains.
No specific considerations.
Parachains already deployed into the Polkadot UC must have a clear plan of action to migrate to an agile Coretime market.
While this proposal does not introduce documentable features per se, adequate documentation must be provided to potential purchasers of Polkadot Coretime. This SHOULD include any alterations to the Polkadot-SDK software collection.
Regular testing through unit tests, integration tests, manual testnet tests, zombie-net tests and fuzzing SHOULD be conducted.
A regular security review SHOULD be conducted prior to deployment through a review by the Web3 Foundation economic research group.
Any final implementation MUST pass a professional external security audit.
RFC-3 proposes a means of implementing the high-level allocations within the Relay-chain.
RFC-5 proposes the API for interacting with Relay-chain.
Additional work should specify the interface for the instantaneous market revenue so that the Coretime-chain can ensure Bulk Coretime placed in the instantaneous market is properly compensated.
Robert Habermeier initially wrote on the subject of Polkadot blockspace-centric in the article Polkadot Blockspace over Blockchains. While not going into details, the article served as an early reframing piece for moving beyond one-slot-per-chain models and building out secondary market infrastructure for resource allocation.
In the Agile Coretime model of the Polkadot Ubiquitous Computer, as proposed in RFC-1 and RFC-3, it is necessary for the allocating parachain (envisioned to be one or more pallets on a specialised Brokerage System Chain) to communicate the core assignments to the Relay-chain, which is responsible for ensuring those assignments are properly enacted.
This is a proposal for the interface which will exist around the Relay-chain in order to communicate this information and instructions.
The background motivation for this interface is splitting out coretime allocation functions and secondary markets from the Relay-chain onto System parachains. A well-understood and general interface is necessary for ensuring the Relay-chain receives coretime allocation instructions from one or more System chains without introducing dependencies on the implementation details of either side.
This content of this RFC was discussed in the Polkdot Fellows channel.
The interface has two sections: The messages which the Relay-chain is able to receive from the allocating parachain (the UMP message types), and messages which the Relay-chain is able to send to the allocating parachain (the DMP message types). These messages are expected to be able to be implemented in a well-known pallet and called with the XCM Transact instruction.
Transact
Future work may include these messages being introduced into the XCM standard.
For request_revenue_info, a successful request should be possible if when is no less than the Relay-chain block number on arrival of the message less 100,000.
request_revenue_info
when
For assign_core, a successful request should be possible if begin is no less than the Relay-chain block number on arrival of the message plus 10 and workload contains no more than 100 items.
assign_core
begin
workload
Standard Polkadot testing and security auditing applies.
RFC-1 proposes a means of determining allocation of Coretime using this interface.
As core functionality moves from the Relay Chain into system chains, so increases the reliance on the liveness of these chains for the use of the network. It is not economically scalable, nor necessary from a game-theoretic perspective, to pay collators large rewards. This RFC proposes a mechanism -- part technical and part social -- for ensuring reliable collator sets that are resilient to attemps to stop any subsytem of the Polkadot protocol.
In order to guarantee access to Polkadot's system, the collators on its system chains must propose blocks (provide liveness) and allow all transactions to eventually be included. That is, some collators may censor transactions, but there must exist one collator in the set who will include a @@ -2063,7 +6239,7 @@ coordinated attempts to stop a single chain from halting or to censor a particul transactions.
In the case that users do not trust this set, this RFC also proposes that each chain always have available collator positions that can be acquired by anyone by placing a bond.
reserve
hold
This protocol builds on the existing Collator Selection pallet and its notion of Invulnerables. Invulnerables are collators (identified by their AccountIds) who @@ -2113,27 +6289,27 @@ approximately:
AccountId
The primary drawback is a reliance on governance for continued treasury funding of infrastructure costs for Invulnerable collators.
The vast majority of cases can be covered by unit testing. Integration test should ensure that the Collator Selection UpdateOrigin, which has permission to modify the Invulnerables and desired number of Candidates, can handle updates over XCM from the system's governance location.
UpdateOrigin
This proposal has very little impact on most users of Polkadot, and should improve the performance of system chains by reducing the number of missed blocks.
As chains have strict PoV size limits, care must be taken in the PoV impact of the session manager. Appropriate benchmarking and tests should ensure that conservative limits are placed on the number of Invulnerables and Candidates.
The primary group affected is Candidate collators, who, after implementation of this RFC, will need to compete in a bond-based election rather than a race to claim a Candidate spot.
This RFC is compatible with the existing implementation and can be handled via upgrades and migration.
There may exist in the future system chains for which this model of collator selection is not appropriate. These chains should be evaluated on a case-by-case basis.
The full nodes of the Polkadot peer-to-peer network maintain a distributed hash table (DHT), which is currently used for full nodes discovery and validators discovery purposes.
This RFC proposes to extend this DHT to be used to discover full nodes of the parachains of Polkadot.
The maintenance of bootnodes has long been an annoyance for everyone.
When a bootnode is newly-deployed or removed, every chain specification must be updated in order to take the update into account. This has lead to various non-optimal solutions, such as pulling chain specifications from GitHub repositories. When it comes to RPC nodes, UX developers often have trouble finding up-to-date addresses of parachain RPC nodes. With the ongoing migration from RPC nodes to light clients, similar problems would happen with chain specifications as well.
Because the list of bootnodes in chain specifications is so annoying to modify, the consequence is that the number of bootnodes is rather low (typically between 2 and 15). In order to better resist downtimes and DoS attacks, a better solution would be to use every node of a certain chain as potential bootnode, rather than special-casing some specific nodes.
While this RFC doesn't solve these problems for relay chains, it aims at solving it for parachains by storing the list of all the full nodes of a parachain on the relay chain DHT.
Assuming that this RFC is implemented, and that light clients are used, deploying a parachain wouldn't require more work than registering it onto the relay chain and starting the collators. There wouldn't be any need for special infrastructure nodes anymore.
This RFC has been opened on my own initiative because I think that this is a good technical solution to a usability problem that many people are encountering and that they don't realize can be solved.
The content of this RFC only applies for parachains and parachain nodes that are "Substrate-compatible". It is in no way mandatory for parachains to comply to this RFC.
Note that "Substrate-compatible" is very loosely defined as "implements the same mechanisms and networking protocols as Substrate". The author of this RFC believes that "Substrate-compatible" should be very precisely specified, but there is controversy on this topic.
While a lot of this RFC concerns the implementation of parachain nodes, it makes use of the resources of the Polkadot chain, and as such it is important to describe them in the Polkadot specification.
The maximum size of a response is set to an arbitrary 16kiB. The responding side should make sure to conform to this limit. Given that fork_id is typically very small and that the only variable-length field is addrs, this is easily achieved by limiting the number of addresses.
fork_id
addrs
Implementers should be aware that addrs might be very large, and are encouraged to limit the number of addrs to an implementation-defined value.
The peer_id and addrs fields are in theory not strictly needed, as the PeerId and addresses could be always equal to the PeerId and addresses of the node being registered as the provider and serving the response. However, the Cumulus implementation currently uses two different networking stacks, one of the parachain and one for the relay chain, using two separate PeerIds and addresses, and as such the PeerId and addresses of the other networking stack must be indicated. Asking them to use only one networking stack wouldn't feasible in a realistic time frame.
peer_id
The values of the genesis_hash and fork_id fields cannot be verified by the requester and are expected to be unused at the moment. Instead, a client that desires connecting to a parachain is expected to obtain the genesis hash and fork ID of the parachain from the parachain chain specification. These fields are included in the networking protocol nonetheless in case an acceptable solution is found in the future, and in order to allow use cases such as discovering parachains in a not-strictly-trusted way.
genesis_hash
Because not all nodes want to be used as bootnodes, implementers are encouraged to provide a way to disable this mechanism. However, it is very much encouraged to leave this mechanism on by default for all parachain nodes.
This mechanism doesn't add or remove any security by itself, as it relies on existing mechanisms. However, if the principle of chain specification bootnodes is entirely replaced with the mechanism described in this RFC (which is the objective), then it becomes important whether the mechanism in this RFC can be abused in order to make a parachain unreachable.
For this reason, an attacker can abuse this mechanism by randomly generating libp2p PeerIds until they find the 20 entries closest to the key representing the target parachain. They are then in control of the parachain bootnodes. Because the key changes periodically and isn't predictable, and assuming that the Polkadot DHT is sufficiently large, it is not realistic for an attack like this to be maintained in the long term.
Furthermore, parachain clients are expected to cache a list of known good nodes on their disk. If the mechanism described in this RFC went down, it would only prevent new nodes from accessing the parachain, while clients that have connected before would not be affected.
The DHT mechanism generally has a low overhead, especially given that publishing providers is done only every 24 hours.
Doing a Kademlia iterative query then sending a provider record shouldn't take more than around 50 kiB in total of bandwidth for the parachain bootnode.
Assuming 1000 parachain full nodes, the 20 Polkadot full nodes corresponding to a specific parachain will each receive a sudden spike of a few megabytes of networking traffic when the key rotates. Again, this is relatively negligible. If this becomes a problem, one can add a random delay before a parachain full node registers itself to be the provider of the key corresponding to BabeApi_next_epoch.
BabeApi_next_epoch
Maybe the biggest uncertainty is the traffic that the 20 Polkadot full nodes will receive from light clients that desire knowing the bootnodes of a parachain. Light clients are generally encouraged to cache the peers that they use between restarts, so they should only query these 20 Polkadot full nodes at their first initialization. If this every becomes a problem, this value of 20 is an arbitrary constant that can be increased for more redundancy.
Irrelevant.
While it fundamentally doesn't change much to this RFC, using BabeApi_currentEpoch and BabeApi_nextEpoch might be inappropriate. I'm not familiar enough with good practices within the runtime to have an opinion here. Should it be an entirely new pallet?
BabeApi_currentEpoch
BabeApi_nextEpoch
It is possible that in the future a client could connect to a parachain without having to rely on a trusted parachain specification.
Improve the networking messages that query storage items from the remote, in order to reduce the bandwidth usage and number of round trips of light clients.
Clients on the Polkadot peer-to-peer network can be divided into two categories: full nodes and light clients. So-called full nodes are nodes that store the content of the chain locally on their disk, while light clients are nodes that don't. In order to access for example the balance of an account, a full node can do a disk read, while a light client needs to send a network message to a full node and wait for the full node to reply with the desired value. This reply is in the form of a Merkle proof, which makes it possible for the light client to verify the exactness of the value.
Unfortunately, this network protocol is suffering from some issues:
Once Polkadot and Kusama will have transitioned to state_version = 1, which modifies the format of the trie entries, it will be possible to generate Merkle proofs that contain only the hashes of values in the storage. Thanks to this, it is already possible to prove the existence of a key without sending its entire value (only its hash), or to prove that a value has changed or not between two blocks (by sending just their hashes). Thus, the only reason why aforementioned issues exist is because the existing networking messages don't give the possibility for the querier to query this. This is what this proposal aims at fixing.
state_version = 1
This is the continuation of https://github.com/w3f/PPPs/pull/10, which itself is the continuation of https://github.com/w3f/PPPs/pull/5.
The protobuf schema of the networking protocol can be found here: https://github.com/paritytech/substrate/blob/5b6519a7ff4a2d3cc424d78bc4830688f3b184c0/client/network/light/src/schema/light.v1.proto
The proposal is to modify this protocol in this way:
@@ -11,6 +11,7 @@ message Request { @@ -2372,26 +6548,26 @@ An alternative could have been to specify the child_trie_info for e Also note that child tries aren't considered as descendants of the main trie when it comes to the includeDescendants flag. In other words, if the request concerns the main trie, no content coming from child tries is ever sent back. This protocol keeps the same maximum response size limit as currently exists (16 MiB). It is not possible for the querier to know in advance whether its query will lead to a reply that exceeds the maximum size. If the reply is too large, the replier should send back only a limited number (but at least one) of requested items in the proof. The querier should then send additional requests for the rest of the items. A response containing none of the requested items is invalid. The server is allowed to silently discard some keys of the request if it judges that the number of requested keys is too high. This is in line with the fact that the server might truncate the response. -Drawbacks +Drawbacks This proposal doesn't handle one specific situation: what if a proof containing a single specific item would exceed the response size limit? For example, if the response size limit was 1 MiB, querying the runtime code (which is typically 1.0 to 1.5 MiB) would be impossible as it's impossible to generate a proof less than 1 MiB. The response size limit is currently 16 MiB, meaning that no single storage item must exceed 16 MiB. Unfortunately, because it's impossible to verify a Merkle proof before having received it entirely, parsing the proof in a streaming way is also not possible. A way to solve this issue would be to Merkle-ize large storage items, so that a proof could include only a portion of a large storage item. Since this would require a change to the trie format, it is not realistically feasible in a short time frame. -Testing, Security, and Privacy +Testing, Security, and Privacy The main security consideration concerns the size of replies and the resources necessary to generate them. It is for example easily possible to ask for all keys and values of the chain, which would take a very long time to generate. Since responses to this networking protocol have a maximum size, the replier should truncate proofs that would lead to the response being too large. Note that it is already possible to send a query that would lead to a very large reply with the existing network protocol. The only thing that this proposal changes is that it would make it less complicated to perform such an attack. Implementers of the replier side should be careful to detect early on when a reply would exceed the maximum reply size, rather than inconditionally generate a reply, as this could take a very large amount of CPU, disk I/O, and memory. Existing implementations might currently be accidentally protected from such an attack thanks to the fact that requests have a maximum size, and thus that the list of keys in the query was bounded. After this proposal, this accidental protection would no longer exist. Malicious server nodes might truncate Merkle proofs even when they don't strictly need to, and it is not possible for the client to (easily) detect this situation. However, malicious server nodes can already do undesirable things such as throttle down their upload bandwidth or simply not respond. There is no need to handle unnecessarily truncated Merkle proofs any differently than a server simply not answering the request. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance It is unclear to the author of the RFC what the performance implications are. Servers are supposed to have limits to the amount of resources they use to respond to requests, and as such the worst that can happen is that light client requests become a bit slower than they currently are. -Ergonomics +Ergonomics Irrelevant. -Compatibility +Compatibility The prior networking protocol is maintained for now. The older version of this protocol could get removed in a long time. -Prior Art and References +Prior Art and References None. This RFC is a clean-up of an existing mechanism. -Unresolved Questions +Unresolved Questions None -Future Directions and Related Material +Future Directions and Related Material The current networking protocol could be deprecated in a long time. Additionally, the current "state requests" protocol (used for warp syncing) could also be deprecated in favor of this one. (source) Table of Contents @@ -2412,13 +6588,13 @@ Also note that child tries aren't considered as descendants of the main trie whe AuthorsJonas Gehrlein -Summary +Summary The Polkadot UC will generate revenue from the sale of available Coretime. The question then arises: how should we handle these revenues? Broadly, there are two reasonable paths – burning the revenue and thereby removing it from total issuance or divert it to the Treasury. This Request for Comment (RFC) presents arguments favoring burning as the preferred mechanism for handling revenues from Coretime sales. -Motivation +Motivation How to handle the revenue accrued from Coretime sales is an important economic question that influences the value of DOT and should be properly discussed before deciding for either of the options. Now is the best time to start this discussion. -Stakeholders +Stakeholders Polkadot DOT token holders. -Explanation +Explanation This RFC discusses potential benefits of burning the revenue accrued from Coretime sales instead of diverting them to Treasury. Here are the following arguments for it. It's in the interest of the Polkadot community to have a consistent and predictable Treasury income, because volatility in the inflow can be damaging, especially in situations when it is insufficient. As such, this RFC operates under the presumption of a steady and sustainable Treasury income flow, which is crucial for the Polkadot community's stability. The assurance of a predictable Treasury income, as outlined in a prior discussion here, or through other equally effective measures, serves as a baseline assumption for this argument. Consequently, we need not concern ourselves with this particular issue here. This naturally begs the question - why should we introduce additional volatility to the Treasury by aligning it with the variable Coretime sales? It's worth noting that Coretime revenues often exhibit an inverse relationship with periods when Treasury spending should ideally be ramped up. During periods of low Coretime utilization (indicated by lower revenue), Treasury should spend more on projects and endeavours to increase the demand for Coretime. This pattern underscores that Coretime sales, by their very nature, are an inconsistent and unpredictable source of funding for the Treasury. Given the importance of maintaining a steady and predictable inflow, it's unnecessary to rely on another volatile mechanism. Some might argue that we could have both: a steady inflow (from inflation) and some added bonus from Coretime sales, but burning the revenue would offer further benefits as described below. @@ -2461,13 +6637,13 @@ Also note that child tries aren't considered as descendants of the main trie whe AuthorsJoe Petrowski -Summary +Summary Since the introduction of the Collectives parachain, many groups have expressed interest in forming new -- or migrating existing groups into -- on-chain collectives. While adding a new collective is relatively simple from a technical standpoint, the Fellowship will need to merge new pallets into the Collectives parachain for each new collective. This RFC proposes a means for the network to ratify a new collective, thus instructing the Fellowship to instate it in the runtime. -Motivation +Motivation Many groups have expressed interest in representing collectives on-chain. Some of these include: Parachain technical fellowship (new) @@ -2483,12 +6659,12 @@ path to having its collective accepted on-chain as part of the protocol. Accepta the Fellowship to include the new collective with a given initial configuration into the runtime. However, the network, not the Fellowship, should ultimately decide which collectives are in the interest of the network. -Stakeholders +Stakeholders Polkadot stakeholders who would like to organize on-chain. Technical Fellowship, in its role of maintaining system runtimes. -Explanation +Explanation The group that wishes to operate an on-chain collective should publish the following information: Charter, including the collective's mandate and how it benefits Polkadot. This would be similar @@ -2522,22 +6698,22 @@ Fellowship would help them identify the pallet indices associated with a given c or not the Fellowship member agrees with removal. Collective removal may also come with other governance calls, for example voiding any scheduled Treasury spends that would fund the given collective. -Drawbacks +Drawbacks Passing a Root origin referendum is slow. However, given the network's investment (in terms of code maintenance and salaries) in a new collective, this is an appropriate step. -Testing, Security, and Privacy +Testing, Security, and Privacy No impacts. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility Generally all new collectives will be in the Collectives parachain. Thus, performance impacts should strictly be limited to this parachain and not affect others. As the majority of logic for collectives is generalized and reusable, we expect most collectives to be instances of similar subsets of modules. That is, new collectives should generally be compatible with UIs and other services that provide collective-related functionality, with little modifications to support new ones. -Prior Art and References +Prior Art and References The launch of the Technical Fellowship, see the initial forum post. -Unresolved Questions +Unresolved Questions None at this time. (source) Table of Contents @@ -2574,13 +6750,13 @@ ones. AuthorsOliver Tale-Yazdi -Summary +Summary Introduces breaking changes to the Core runtime API by letting Core::initialize_block return an enum. The versions of Core is bumped from 4 to 5. -Motivation +Motivation The main feature that motivates this RFC are Multi-Block-Migrations (MBM); these make it possible to split a migration over multiple blocks. Further it would be nice to not hinder the possibility of implementing a new hook poll, that runs at the beginning of the block when there are no MBMs and has access to AllPalletsWithSystem. This hook can then be used to replace the use of on_initialize and on_finalize for non-deadline critical logic. In a similar fashion, it should not hinder the future addition of a System::PostInherents callback that always runs after all inherents were applied. -Stakeholders +Stakeholders Substrate Maintainers: They have to implement this, including tests, audit and maintenance burden. @@ -2588,7 +6764,7 @@ maintenance burden. Polkadot Parachain Teams: They have to adapt to the breaking changes but then eventually have multi-block migrations available. -Explanation +Explanation Core::initialize_block This runtime API function is changed from returning () to ExtrinsicInclusionMode: fn initialize_block(header: &<Block as BlockT>::Header) @@ -2609,23 +6785,23 @@ multi-block migrations available. 1. Multi-Block-Migrations: The runtime is being put into lock-down mode for the duration of the migration process by returning OnlyInherents from initialize_block. This ensures that no user provided transaction can interfere with the migration process. It is absolutely necessary to ensure this, otherwise a transaction could call into un-migrated storage and violate storage invariants. 2. poll is possible by using apply_extrinsic as entry-point and not hindered by this approach. It would not be possible to use a pallet inherent like System::last_inherent to achieve this for two reasons: First is that pallets do not have access to AllPalletsWithSystem which is required to invoke the poll hook on all pallets. Second is that the runtime does currently not enforce an order of inherents. 3. System::PostInherents can be done in the same manner as poll. -Drawbacks +Drawbacks The previous drawback of cementing the order of inherents has been addressed and removed by redesigning the approach. No further drawbacks have been identified thus far. -Testing, Security, and Privacy +Testing, Security, and Privacy The new logic of initialize_block can be tested by checking that the block-builder will skip transactions when OnlyInherents is returned. Security: n/a Privacy: n/a -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance The performance overhead is minimal in the sense that no clutter was added after fulfilling the requirements. The only performance difference is that initialize_block also returns an enum that needs to be passed through the WASM boundary. This should be negligible. -Ergonomics +Ergonomics The new interface allows for more extensible runtime logic. In the future, this will be utilized for multi-block-migrations which should be a huge ergonomic advantage for parachain developers. -Compatibility +Compatibility The advice here is OPTIONAL and outside of the RFC. To not degrade user experience, it is recommended to ensure that an updated node can still import historic blocks. -Prior Art and References +Prior Art and References The RFC is currently being implemented in polkadot-sdk#1781 (formerly substrate#14275). Related issues and merge requests: @@ -2635,14 +6811,14 @@ transactions There is no module hook after inherents and before transactions -Unresolved Questions +Unresolved Questions Please suggest a better name for BlockExecutiveMode. We already tried: RuntimeExecutiveMode, ExtrinsicInclusionMode. The names of the modes Normal and Minimal were also called AllExtrinsics and OnlyInherents, so if you have naming preferences; please post them. => renamed to ExtrinsicInclusionMode Is post_inherents more consistent instead of last_inherent? Then we should change it. => renamed to last_inherent -Future Directions and Related Material +Future Directions and Related Material The long-term future here is to move the block building logic into the runtime. Currently there is a tight dance between the block author and the runtime; the author has to call into different runtime functions in quick succession and exact order. Any misstep causes the block to be invalid. This can be unified and simplified by moving both parts into the runtime. (source) @@ -2679,14 +6855,14 @@ This can be unified and simplified by moving both parts into the runtime. AuthorsBryan Chen -Summary +Summary This RFC proposes a set of changes to the parachain lock mechanism. The goal is to allow a parachain manager to self-service the parachain without root track governance action. This is achieved by remove existing lock conditions and only lock a parachain when: A parachain manager explicitly lock the parachain OR a parachain block is produced successfully -Motivation +Motivation The manager of a parachain has permission to manage the parachain when the parachain is unlocked. Parachains are by default locked when onboarded to a slot. This requires the parachain wasm/genesis must be valid, otherwise a root track governance action on relaychain is required to update the parachain. The current reliance on root track governance actions for managing parachains can be time-consuming and burdensome. This RFC aims to address this technical difficulty by allowing parachain managers to take self-service actions, rather than relying on general public voting. The key scenarios this RFC seeks to improve are: @@ -2698,19 +6874,19 @@ This can be unified and simplified by moving both parts into the runtime. Perform lease renewal for an existing parachain. One way to perform lease renewal for a parachain is by doing a least swap with another parachain with a longer lease. This requires the other parachain must be operational and able to perform XCM transact call into relaychain to dispatch the swap call. Combined with the overhead of setting up a new parachain, this is an time consuming and expensive process. Ideally, the parachain manager should be able to perform the lease swap call without having a running parachain2. -Requirements +Requirements A parachain manager SHOULD be able to rescue a parachain by updating the wasm/genesis without root track governance action. A parachain manager MUST NOT be able to update the wasm/genesis if the parachain is locked. A parachain SHOULD be locked when it successfully produced the first block. A parachain manager MUST be able to perform lease swap without having a running parachain. -Stakeholders +Stakeholders Parachain teams Parachain users -Explanation +Explanation Status quo A parachain can either be locked or unlocked3. With parachain locked, the parachain manager does not have any privileges. With parachain unlocked, the parachain manager can perform following actions with the paras_registrar pallet: @@ -2750,31 +6926,31 @@ This can be unified and simplified by moving both parts into the runtime. Parachain never produced a block. Including from expired leases. Parachain manager never explicitly lock the parachain. -Drawbacks +Drawbacks Parachain locks are designed in such way to ensure the decentralization of parachains. If parachains are not locked when it should be, it could introduce centralization risk for new parachains. For example, one possible scenario is that a collective may decide to launch a parachain fully decentralized. However, if the parachain is unable to produce block, the parachain manager will be able to replace the wasm and genesis without the consent of the collective. It is considered this risk is tolerable as it requires the wasm/genesis to be invalid at first place. It is not yet practically possible to develop a parachain without any centralized risk currently. Another case is that a parachain team may decide to use crowdloan to help secure a slot lease. Previously, creating a crowdloan will lock a parachain. This means crowdloan participants will know exactly the genesis of the parachain for the crowdloan they are participating. However, this actually providers little assurance to crowdloan participants. For example, if the genesis block is determined before a crowdloan is started, it is not possible to have onchain mechanism to enforce reward distributions for crowdloan participants. They always have to rely on the parachain team to fulfill the promise after the parachain is alive. Existing operational parachains will not be impacted. -Testing, Security, and Privacy +Testing, Security, and Privacy The implementation of this RFC will be tested on testnets (Rococo and Westend) first. An audit maybe required to ensure the implementation does not introduce unwanted side effects. There is no privacy related concerns. -Performance +Performance This RFC should not introduce any performance impact. -Ergonomics +Ergonomics This RFC should improve the developer experiences for new and existing parachain teams -Compatibility +Compatibility This RFC is fully compatibility with existing interfaces. -Prior Art and References +Prior Art and References Parachain Slot Extension Story: https://github.com/paritytech/polkadot/issues/4758 Allow parachain to renew lease without actually run another parachain: https://github.com/paritytech/polkadot/issues/6685 Always treat parachain that never produced block for a significant amount of time as unlocked: https://github.com/paritytech/polkadot/issues/7539 -Unresolved Questions +Unresolved Questions None at this stage. -Future Directions and Related Material +Future Directions and Related Material This RFC is only intended to be a short term solution. Slots will be removed in future and lock mechanism is likely going to be replaced with a more generalized parachain manage & recovery system in future. Therefore long term impacts of this RFC are not considered. 1 https://github.com/paritytech/cumulus/issues/377 @@ -2826,11 +7002,11 @@ This can be unified and simplified by moving both parts into the runtime. AuthorsJonas Gehrlein -Summary +Summary This document proposes a restructuring of the bulk markets in Polkadot's coretime allocation system to improve efficiency and fairness. The proposal suggests splitting the BULK_PERIOD into three consecutive phases: MARKET_PERIOD, RENEWAL_PERIOD, and SETTLEMENT_PERIOD. This structure enables market-driven price discovery through a clearing-price Dutch auction, followed by renewal offers during the RENEWAL_PERIOD. With all coretime consumers paying a unified price, we propose removing all liquidity restrictions on cores purchased either during the initial market phase or renewed during the renewal phase. This allows a meaningful SETTLEMENT_PERIOD, during which final agreements and deals between coretime consumers can be orchestrated on the social layer—complementing the agility this system seeks to establish. In the new design, we obtain a uniform price, the clearing_price, which anchors new entrants and current tenants. To complement market-based price discovery, the design includes a dynamic reserve price adjustment mechanism based on actual core consumption. Together, these two components ensure robust price discovery while mitigating price collapse in cases of slight underutilization or collusive behavior. -Motivation +Motivation After exposing the initial system introduced in RFC-1 to real-world conditions, several weaknesses have become apparent. These lie especially in the fact that cores captured at very low prices are removed from the open market and can effectively be retained indefinitely, as renewal costs are minimal. The key issue here is the absence of price anchoring, which results in two divergent price paths: one for the initial purchase on the open market, and another fully deterministic one via the renewal bump mechanism. This proposal addresses these issues by anchoring all prices to a value derived from the market, while still preserving necessary privileges for current coretime consumers. The goal is to produce robust results across varying demand conditions (low, high, or volatile). In particular, this proposal introduces the following key changes: @@ -2841,15 +7017,15 @@ This can be unified and simplified by moving both parts into the runtime. The premise of this proposal is to offer a straightforward design that discovers the price of coretime within a period as a clearing_price. Long-term coretime holders still retain the privilege to keep their cores if they can pay the price discovered by the market (with some premium for that privilege). The proposed model aims to strike a balance between leveraging market forces for allocation while operating within defined bounds. In particular, prices are capped within a BULK_PERIOD, which gives some certainty about prices to existing teams. It must be noted, however, that under high demand, prices could increase exponentially between multiple market cycles. This is a necessary feature to ensure proper price discovery and efficient coretime allocation. Ultimately, the framework proposed here seeks to adhere to all requirements originally stated in RFC-1. -Stakeholders +Stakeholders Primary stakeholder sets are: Protocol researchers, developers, and the Polkadot Fellowship. Polkadot Parachain teams both present and future, and their users. Polkadot DOT token holders. -Explanation -Overview +Explanation +Overview The BULK_PERIOD has been restructured into two primary segments: the MARKET_PERIOD and the RENEWAL_PERIOD, along with an auxiliarySETTLEMENT_PERIOD. The latter does not require any active participation from the coretime system chain except to simply execute transfers of ownership between market participants. A significant departure from the current design lies in the timing of renewals, which now occur after the market phase. This adjustment aims to harmonize renewal prices with their market counterparts, ensuring a more consistent and equitable pricing model. Market Period (14 days) During the market period, core sales are conducted through a well-established clearing-price Dutch auction that features a reserve_price. Since the auction format is a descending clock, the starting price is initialized at the opening_price. The price then descends linearly over the duration of the MARKET_PERIOD toward the reserve_price, which serves as the minimum price for coretime within that period. @@ -2960,7 +7136,7 @@ To mitigate this, we propose preventing the market from closing at the ope -Prior Art and References +Prior Art and References This RFC builds extensively on the available ideas put forward in RFC-1. Additionally, I want to express a special thanks to Samuel Haefner, Shahar Dobzinski, and Alistair Stewart for fruitful discussions and helping me structure my thoughts. (source) @@ -2988,19 +7164,19 @@ To mitigate this, we propose preventing the market from closing at the ope Authors@brenzi for Encointer Association, 8000 Zurich, Switzerland -Summary +Summary Encointer is a system chain on Kusama since Jan 2022 and has been developed and maintained by the Encointer association. This RFC proposes to treat Encointer like any other system chain and include it in the fellowship repo with this PR. -Motivation +Motivation Encointer does not seek to be in control of its runtime repository. As a decentralized system, the fellowship has a more suitable structure to maintain a system chain runtime repo than the Encointer association does. Also, Encointer aims to update its runtime in batches with other system chains in order to have consistency for interoperability across system chains. -Stakeholders +Stakeholders Fellowship: Will continue to take upon them the review and auditing work for the Encointer runtime, but the process is streamlined with other system chains and therefore less time-consuming compared to the separate repo and CI process we currently have. Kusama Network: Tokenholders can easily see the changes of all system chains in one place. Encointer Association: Further decentralization of the Encointer Network necessities like devops. Encointer devs: Being able to work directly in the Fellowship runtimes repo to streamline and synergize with other developers. -Explanation +Explanation Our PR has all details about our runtime and how we would move it into the fellowship repo. Noteworthy: All Encointer-specific pallets will still be located in encointer's repo for the time being: https://github.com/encointer/pallets It will still be the duty of the Encointer team to keep its runtime up to date and provide adequate test fixtures. Frequent dependency bumps with Polkadot releases would be beneficial for interoperability and could be streamlined with other system chains but that will not be a duty of fellowship. Whenever possible, all system chains could be upgraded jointly (including Encointer) with a batch referendum. @@ -3009,17 +7185,17 @@ To mitigate this, we propose preventing the market from closing at the ope Encointer will publish all its crates crates.io Encointer does not carry out external auditing of its runtime nor pallets. It would be beneficial but not a requirement from our side if Encointer could join the auditing process of other system chains. -Drawbacks +Drawbacks Other than all other system chains, development and maintenance of the Encointer Network is mainly financed by the KSM Treasury and possibly the DOT Treasury in the future. Encointer is dedicated to maintaining its network and runtime code for as long as possible, but there is a dependency on funding which is not in the hands of the fellowship. The only risk in the context of funding, however, is that the Encointer runtime will see less frequent updates if there's less funding. -Testing, Security, and Privacy +Testing, Security, and Privacy No changes to the existing system are proposed. Only changes to how maintenance is organized. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility No changes -Prior Art and References +Prior Art and References Existing Encointer runtime repo -Unresolved Questions +Unresolved Questions None identified -Future Directions and Related Material +Future Directions and Related Material More info on Encointer: encointer.org (source) Table of Contents @@ -3939,11 +8115,11 @@ other privacy-enhancing mechanisms to address this concern. AuthorsJoe Petrowski, Gavin Wood -Summary +Summary The Relay Chain contains most of the core logic for the Polkadot network. While this was necessary prior to the launch of parachains and development of XCM, most of this logic can exist in parachains. This is a proposal to migrate several subsystems into system parachains. -Motivation +Motivation Polkadot's scaling approach allows many distinct state machines (known generally as parachains) to operate with common guarantees about the validity and security of their state transitions. Polkadot provides these common guarantees by executing the state transitions on a strict subset (a backing @@ -3955,13 +8131,13 @@ blockspace) to the network. By minimising state transition logic on the Relay Chain by migrating it into "system chains" -- a set of parachains that, with the Relay Chain, make up the Polkadot protocol -- the Polkadot Ubiquitous Computer can maximise its primary offering: secure blockspace. -Stakeholders +Stakeholders Parachains that interact with affected logic on the Relay Chain; Core protocol and XCM format developers; Tooling, block explorer, and UI developers. -Explanation +Explanation The following pallets and subsystems are good candidates to migrate from the Relay Chain: Identity @@ -4107,36 +8283,36 @@ sensible to rehearse a migration. Staking is the subsystem most constrained by PoV limits. Ensuring that elections, payouts, session changes, offences/slashes, etc. work in a parachain on Kusama -- with its larger validator set -- will give confidence to the chain's robustness on Polkadot. -Drawbacks +Drawbacks These subsystems will have reduced resources in cores than on the Relay Chain. Staking in particular may require some optimizations to deal with constraints. -Testing, Security, and Privacy +Testing, Security, and Privacy Standard audit/review requirements apply. More powerful multi-chain integration test tools would be useful in developement. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility Describe the impact of the proposal on the exposed functionality of Polkadot. -Performance +Performance This is an optimization. The removal of public/user transactions on the Relay Chain ensures that its primary resources are allocated to system performance. -Ergonomics +Ergonomics This proposal alters very little for coretime users (e.g. parachain developers). Application developers will need to interact with multiple chains, making ergonomic light client tools particularly important for application development. For existing parachains that interact with these subsystems, they will need to configure their runtimes to recognize the new locations in the network. -Compatibility +Compatibility Implementing this proposal will require some changes to pallet APIs and/or a pub-sub protocol. Application developers will need to interact with multiple chains in the network. -Prior Art and References +Prior Art and References Transactionless Relay-chain Moving Staking off the Relay Chain -Unresolved Questions +Unresolved Questions There remain some implementation questions, like how to use balances for both Staking and Governance. See, for example, Moving Staking off the Relay Chain. -Future Directions and Related Material +Future Directions and Related Material Ideally the Relay Chain becomes transactionless, such that not even balances are represented there. With Staking and Governance off the Relay Chain, this is not an unreasonable next step. With Identity on Polkadot, Kusama may opt to drop its People Chain. @@ -4171,13 +8347,13 @@ With Staking and Governance off the Relay Chain, this is not an unreasonable nex AuthorsVedhavyas Singareddi -Summary +Summary At the moment, we have system_version field on RuntimeVersion that derives which state version is used for the Storage. We have a use case where we want extrinsics root is derived using StateVersion::V1. Without defining a new field under RuntimeVersion, we would like to propose adding system_version that can be used to derive both storage and extrinsic state version. -Motivation +Motivation Since the extrinsic state version is always StateVersion::V0, deriving extrinsic root requires full extrinsic data. This would be problematic when we need to verify the extrinsics root if the extrinsic sizes are bigger. This problem is further explored in https://github.com/polkadot-fellows/RFCs/issues/19 @@ -4189,11 +8365,11 @@ One of the main challenge here is some extrinsics could be big enough that this included in the Consensus block due to Block's weight restriction. If the extrinsic root is derived using StateVersion::V1, then we do not need to pass the full extrinsic data but rather at maximum, 32 byte of extrinsic data. -Stakeholders +Stakeholders Technical Fellowship, in its role of maintaining system runtimes. -Explanation +Explanation In order to use project specific StateVersion for extrinsic roots, we proposed an implementation that introduced parameter to frame_system::Config but that unfortunately did not feel correct. @@ -4219,26 +8395,26 @@ pub const VERSION: RuntimeVersion = RuntimeVersion { system_version: 1, }; }
child_trie_info
includeDescendants
This protocol keeps the same maximum response size limit as currently exists (16 MiB). It is not possible for the querier to know in advance whether its query will lead to a reply that exceeds the maximum size. If the reply is too large, the replier should send back only a limited number (but at least one) of requested items in the proof. The querier should then send additional requests for the rest of the items. A response containing none of the requested items is invalid.
The server is allowed to silently discard some keys of the request if it judges that the number of requested keys is too high. This is in line with the fact that the server might truncate the response.
This proposal doesn't handle one specific situation: what if a proof containing a single specific item would exceed the response size limit? For example, if the response size limit was 1 MiB, querying the runtime code (which is typically 1.0 to 1.5 MiB) would be impossible as it's impossible to generate a proof less than 1 MiB. The response size limit is currently 16 MiB, meaning that no single storage item must exceed 16 MiB.
Unfortunately, because it's impossible to verify a Merkle proof before having received it entirely, parsing the proof in a streaming way is also not possible.
A way to solve this issue would be to Merkle-ize large storage items, so that a proof could include only a portion of a large storage item. Since this would require a change to the trie format, it is not realistically feasible in a short time frame.
The main security consideration concerns the size of replies and the resources necessary to generate them. It is for example easily possible to ask for all keys and values of the chain, which would take a very long time to generate. Since responses to this networking protocol have a maximum size, the replier should truncate proofs that would lead to the response being too large. Note that it is already possible to send a query that would lead to a very large reply with the existing network protocol. The only thing that this proposal changes is that it would make it less complicated to perform such an attack.
Implementers of the replier side should be careful to detect early on when a reply would exceed the maximum reply size, rather than inconditionally generate a reply, as this could take a very large amount of CPU, disk I/O, and memory. Existing implementations might currently be accidentally protected from such an attack thanks to the fact that requests have a maximum size, and thus that the list of keys in the query was bounded. After this proposal, this accidental protection would no longer exist.
Malicious server nodes might truncate Merkle proofs even when they don't strictly need to, and it is not possible for the client to (easily) detect this situation. However, malicious server nodes can already do undesirable things such as throttle down their upload bandwidth or simply not respond. There is no need to handle unnecessarily truncated Merkle proofs any differently than a server simply not answering the request.
It is unclear to the author of the RFC what the performance implications are. Servers are supposed to have limits to the amount of resources they use to respond to requests, and as such the worst that can happen is that light client requests become a bit slower than they currently are.
The prior networking protocol is maintained for now. The older version of this protocol could get removed in a long time.
None. This RFC is a clean-up of an existing mechanism.
The current networking protocol could be deprecated in a long time. Additionally, the current "state requests" protocol (used for warp syncing) could also be deprecated in favor of this one.
The Polkadot UC will generate revenue from the sale of available Coretime. The question then arises: how should we handle these revenues? Broadly, there are two reasonable paths – burning the revenue and thereby removing it from total issuance or divert it to the Treasury. This Request for Comment (RFC) presents arguments favoring burning as the preferred mechanism for handling revenues from Coretime sales.
How to handle the revenue accrued from Coretime sales is an important economic question that influences the value of DOT and should be properly discussed before deciding for either of the options. Now is the best time to start this discussion.
Polkadot DOT token holders.
This RFC discusses potential benefits of burning the revenue accrued from Coretime sales instead of diverting them to Treasury. Here are the following arguments for it.
It's in the interest of the Polkadot community to have a consistent and predictable Treasury income, because volatility in the inflow can be damaging, especially in situations when it is insufficient. As such, this RFC operates under the presumption of a steady and sustainable Treasury income flow, which is crucial for the Polkadot community's stability. The assurance of a predictable Treasury income, as outlined in a prior discussion here, or through other equally effective measures, serves as a baseline assumption for this argument.
Consequently, we need not concern ourselves with this particular issue here. This naturally begs the question - why should we introduce additional volatility to the Treasury by aligning it with the variable Coretime sales? It's worth noting that Coretime revenues often exhibit an inverse relationship with periods when Treasury spending should ideally be ramped up. During periods of low Coretime utilization (indicated by lower revenue), Treasury should spend more on projects and endeavours to increase the demand for Coretime. This pattern underscores that Coretime sales, by their very nature, are an inconsistent and unpredictable source of funding for the Treasury. Given the importance of maintaining a steady and predictable inflow, it's unnecessary to rely on another volatile mechanism. Some might argue that we could have both: a steady inflow (from inflation) and some added bonus from Coretime sales, but burning the revenue would offer further benefits as described below.
Since the introduction of the Collectives parachain, many groups have expressed interest in forming new -- or migrating existing groups into -- on-chain collectives. While adding a new collective is relatively simple from a technical standpoint, the Fellowship will need to merge new pallets into the Collectives parachain for each new collective. This RFC proposes a means for the network to ratify a new collective, thus instructing the Fellowship to instate it in the runtime.
Many groups have expressed interest in representing collectives on-chain. Some of these include:
The group that wishes to operate an on-chain collective should publish the following information:
Collective removal may also come with other governance calls, for example voiding any scheduled Treasury spends that would fund the given collective.
Passing a Root origin referendum is slow. However, given the network's investment (in terms of code maintenance and salaries) in a new collective, this is an appropriate step.
No impacts.
Generally all new collectives will be in the Collectives parachain. Thus, performance impacts should strictly be limited to this parachain and not affect others. As the majority of logic for collectives is generalized and reusable, we expect most collectives to be instances of similar subsets of modules. That is, new collectives should generally be compatible with UIs and other services that provide collective-related functionality, with little modifications to support new ones.
The launch of the Technical Fellowship, see the initial forum post.
Introduces breaking changes to the Core runtime API by letting Core::initialize_block return an enum. The versions of Core is bumped from 4 to 5.
Core
Core::initialize_block
The main feature that motivates this RFC are Multi-Block-Migrations (MBM); these make it possible to split a migration over multiple blocks. Further it would be nice to not hinder the possibility of implementing a new hook poll, that runs at the beginning of the block when there are no MBMs and has access to AllPalletsWithSystem. This hook can then be used to replace the use of on_initialize and on_finalize for non-deadline critical logic. In a similar fashion, it should not hinder the future addition of a System::PostInherents callback that always runs after all inherents were applied.
poll
AllPalletsWithSystem
on_initialize
on_finalize
System::PostInherents
This runtime API function is changed from returning () to ExtrinsicInclusionMode:
()
ExtrinsicInclusionMode
fn initialize_block(header: &<Block as BlockT>::Header) @@ -2609,23 +6785,23 @@ multi-block migrations available. 1. Multi-Block-Migrations: The runtime is being put into lock-down mode for the duration of the migration process by returning OnlyInherents from initialize_block. This ensures that no user provided transaction can interfere with the migration process. It is absolutely necessary to ensure this, otherwise a transaction could call into un-migrated storage and violate storage invariants. 2. poll is possible by using apply_extrinsic as entry-point and not hindered by this approach. It would not be possible to use a pallet inherent like System::last_inherent to achieve this for two reasons: First is that pallets do not have access to AllPalletsWithSystem which is required to invoke the poll hook on all pallets. Second is that the runtime does currently not enforce an order of inherents. 3. System::PostInherents can be done in the same manner as poll. -Drawbacks +Drawbacks The previous drawback of cementing the order of inherents has been addressed and removed by redesigning the approach. No further drawbacks have been identified thus far. -Testing, Security, and Privacy +Testing, Security, and Privacy The new logic of initialize_block can be tested by checking that the block-builder will skip transactions when OnlyInherents is returned. Security: n/a Privacy: n/a -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance The performance overhead is minimal in the sense that no clutter was added after fulfilling the requirements. The only performance difference is that initialize_block also returns an enum that needs to be passed through the WASM boundary. This should be negligible. -Ergonomics +Ergonomics The new interface allows for more extensible runtime logic. In the future, this will be utilized for multi-block-migrations which should be a huge ergonomic advantage for parachain developers. -Compatibility +Compatibility The advice here is OPTIONAL and outside of the RFC. To not degrade user experience, it is recommended to ensure that an updated node can still import historic blocks. -Prior Art and References +Prior Art and References The RFC is currently being implemented in polkadot-sdk#1781 (formerly substrate#14275). Related issues and merge requests: @@ -2635,14 +6811,14 @@ transactions There is no module hook after inherents and before transactions -Unresolved Questions +Unresolved Questions Please suggest a better name for BlockExecutiveMode. We already tried: RuntimeExecutiveMode, ExtrinsicInclusionMode. The names of the modes Normal and Minimal were also called AllExtrinsics and OnlyInherents, so if you have naming preferences; please post them. => renamed to ExtrinsicInclusionMode Is post_inherents more consistent instead of last_inherent? Then we should change it. => renamed to last_inherent -Future Directions and Related Material +Future Directions and Related Material The long-term future here is to move the block building logic into the runtime. Currently there is a tight dance between the block author and the runtime; the author has to call into different runtime functions in quick succession and exact order. Any misstep causes the block to be invalid. This can be unified and simplified by moving both parts into the runtime. (source) @@ -2679,14 +6855,14 @@ This can be unified and simplified by moving both parts into the runtime. AuthorsBryan Chen -Summary +Summary This RFC proposes a set of changes to the parachain lock mechanism. The goal is to allow a parachain manager to self-service the parachain without root track governance action. This is achieved by remove existing lock conditions and only lock a parachain when: A parachain manager explicitly lock the parachain OR a parachain block is produced successfully -Motivation +Motivation The manager of a parachain has permission to manage the parachain when the parachain is unlocked. Parachains are by default locked when onboarded to a slot. This requires the parachain wasm/genesis must be valid, otherwise a root track governance action on relaychain is required to update the parachain. The current reliance on root track governance actions for managing parachains can be time-consuming and burdensome. This RFC aims to address this technical difficulty by allowing parachain managers to take self-service actions, rather than relying on general public voting. The key scenarios this RFC seeks to improve are: @@ -2698,19 +6874,19 @@ This can be unified and simplified by moving both parts into the runtime. Perform lease renewal for an existing parachain. One way to perform lease renewal for a parachain is by doing a least swap with another parachain with a longer lease. This requires the other parachain must be operational and able to perform XCM transact call into relaychain to dispatch the swap call. Combined with the overhead of setting up a new parachain, this is an time consuming and expensive process. Ideally, the parachain manager should be able to perform the lease swap call without having a running parachain2. -Requirements +Requirements A parachain manager SHOULD be able to rescue a parachain by updating the wasm/genesis without root track governance action. A parachain manager MUST NOT be able to update the wasm/genesis if the parachain is locked. A parachain SHOULD be locked when it successfully produced the first block. A parachain manager MUST be able to perform lease swap without having a running parachain. -Stakeholders +Stakeholders Parachain teams Parachain users -Explanation +Explanation Status quo A parachain can either be locked or unlocked3. With parachain locked, the parachain manager does not have any privileges. With parachain unlocked, the parachain manager can perform following actions with the paras_registrar pallet: @@ -2750,31 +6926,31 @@ This can be unified and simplified by moving both parts into the runtime. Parachain never produced a block. Including from expired leases. Parachain manager never explicitly lock the parachain. -Drawbacks +Drawbacks Parachain locks are designed in such way to ensure the decentralization of parachains. If parachains are not locked when it should be, it could introduce centralization risk for new parachains. For example, one possible scenario is that a collective may decide to launch a parachain fully decentralized. However, if the parachain is unable to produce block, the parachain manager will be able to replace the wasm and genesis without the consent of the collective. It is considered this risk is tolerable as it requires the wasm/genesis to be invalid at first place. It is not yet practically possible to develop a parachain without any centralized risk currently. Another case is that a parachain team may decide to use crowdloan to help secure a slot lease. Previously, creating a crowdloan will lock a parachain. This means crowdloan participants will know exactly the genesis of the parachain for the crowdloan they are participating. However, this actually providers little assurance to crowdloan participants. For example, if the genesis block is determined before a crowdloan is started, it is not possible to have onchain mechanism to enforce reward distributions for crowdloan participants. They always have to rely on the parachain team to fulfill the promise after the parachain is alive. Existing operational parachains will not be impacted. -Testing, Security, and Privacy +Testing, Security, and Privacy The implementation of this RFC will be tested on testnets (Rococo and Westend) first. An audit maybe required to ensure the implementation does not introduce unwanted side effects. There is no privacy related concerns. -Performance +Performance This RFC should not introduce any performance impact. -Ergonomics +Ergonomics This RFC should improve the developer experiences for new and existing parachain teams -Compatibility +Compatibility This RFC is fully compatibility with existing interfaces. -Prior Art and References +Prior Art and References Parachain Slot Extension Story: https://github.com/paritytech/polkadot/issues/4758 Allow parachain to renew lease without actually run another parachain: https://github.com/paritytech/polkadot/issues/6685 Always treat parachain that never produced block for a significant amount of time as unlocked: https://github.com/paritytech/polkadot/issues/7539 -Unresolved Questions +Unresolved Questions None at this stage. -Future Directions and Related Material +Future Directions and Related Material This RFC is only intended to be a short term solution. Slots will be removed in future and lock mechanism is likely going to be replaced with a more generalized parachain manage & recovery system in future. Therefore long term impacts of this RFC are not considered. 1 https://github.com/paritytech/cumulus/issues/377 @@ -2826,11 +7002,11 @@ This can be unified and simplified by moving both parts into the runtime. AuthorsJonas Gehrlein -Summary +Summary This document proposes a restructuring of the bulk markets in Polkadot's coretime allocation system to improve efficiency and fairness. The proposal suggests splitting the BULK_PERIOD into three consecutive phases: MARKET_PERIOD, RENEWAL_PERIOD, and SETTLEMENT_PERIOD. This structure enables market-driven price discovery through a clearing-price Dutch auction, followed by renewal offers during the RENEWAL_PERIOD. With all coretime consumers paying a unified price, we propose removing all liquidity restrictions on cores purchased either during the initial market phase or renewed during the renewal phase. This allows a meaningful SETTLEMENT_PERIOD, during which final agreements and deals between coretime consumers can be orchestrated on the social layer—complementing the agility this system seeks to establish. In the new design, we obtain a uniform price, the clearing_price, which anchors new entrants and current tenants. To complement market-based price discovery, the design includes a dynamic reserve price adjustment mechanism based on actual core consumption. Together, these two components ensure robust price discovery while mitigating price collapse in cases of slight underutilization or collusive behavior. -Motivation +Motivation After exposing the initial system introduced in RFC-1 to real-world conditions, several weaknesses have become apparent. These lie especially in the fact that cores captured at very low prices are removed from the open market and can effectively be retained indefinitely, as renewal costs are minimal. The key issue here is the absence of price anchoring, which results in two divergent price paths: one for the initial purchase on the open market, and another fully deterministic one via the renewal bump mechanism. This proposal addresses these issues by anchoring all prices to a value derived from the market, while still preserving necessary privileges for current coretime consumers. The goal is to produce robust results across varying demand conditions (low, high, or volatile). In particular, this proposal introduces the following key changes: @@ -2841,15 +7017,15 @@ This can be unified and simplified by moving both parts into the runtime. The premise of this proposal is to offer a straightforward design that discovers the price of coretime within a period as a clearing_price. Long-term coretime holders still retain the privilege to keep their cores if they can pay the price discovered by the market (with some premium for that privilege). The proposed model aims to strike a balance between leveraging market forces for allocation while operating within defined bounds. In particular, prices are capped within a BULK_PERIOD, which gives some certainty about prices to existing teams. It must be noted, however, that under high demand, prices could increase exponentially between multiple market cycles. This is a necessary feature to ensure proper price discovery and efficient coretime allocation. Ultimately, the framework proposed here seeks to adhere to all requirements originally stated in RFC-1. -Stakeholders +Stakeholders Primary stakeholder sets are: Protocol researchers, developers, and the Polkadot Fellowship. Polkadot Parachain teams both present and future, and their users. Polkadot DOT token holders. -Explanation -Overview +Explanation +Overview The BULK_PERIOD has been restructured into two primary segments: the MARKET_PERIOD and the RENEWAL_PERIOD, along with an auxiliarySETTLEMENT_PERIOD. The latter does not require any active participation from the coretime system chain except to simply execute transfers of ownership between market participants. A significant departure from the current design lies in the timing of renewals, which now occur after the market phase. This adjustment aims to harmonize renewal prices with their market counterparts, ensuring a more consistent and equitable pricing model. Market Period (14 days) During the market period, core sales are conducted through a well-established clearing-price Dutch auction that features a reserve_price. Since the auction format is a descending clock, the starting price is initialized at the opening_price. The price then descends linearly over the duration of the MARKET_PERIOD toward the reserve_price, which serves as the minimum price for coretime within that period. @@ -2960,7 +7136,7 @@ To mitigate this, we propose preventing the market from closing at the ope -Prior Art and References +Prior Art and References This RFC builds extensively on the available ideas put forward in RFC-1. Additionally, I want to express a special thanks to Samuel Haefner, Shahar Dobzinski, and Alistair Stewart for fruitful discussions and helping me structure my thoughts. (source) @@ -2988,19 +7164,19 @@ To mitigate this, we propose preventing the market from closing at the ope Authors@brenzi for Encointer Association, 8000 Zurich, Switzerland -Summary +Summary Encointer is a system chain on Kusama since Jan 2022 and has been developed and maintained by the Encointer association. This RFC proposes to treat Encointer like any other system chain and include it in the fellowship repo with this PR. -Motivation +Motivation Encointer does not seek to be in control of its runtime repository. As a decentralized system, the fellowship has a more suitable structure to maintain a system chain runtime repo than the Encointer association does. Also, Encointer aims to update its runtime in batches with other system chains in order to have consistency for interoperability across system chains. -Stakeholders +Stakeholders Fellowship: Will continue to take upon them the review and auditing work for the Encointer runtime, but the process is streamlined with other system chains and therefore less time-consuming compared to the separate repo and CI process we currently have. Kusama Network: Tokenholders can easily see the changes of all system chains in one place. Encointer Association: Further decentralization of the Encointer Network necessities like devops. Encointer devs: Being able to work directly in the Fellowship runtimes repo to streamline and synergize with other developers. -Explanation +Explanation Our PR has all details about our runtime and how we would move it into the fellowship repo. Noteworthy: All Encointer-specific pallets will still be located in encointer's repo for the time being: https://github.com/encointer/pallets It will still be the duty of the Encointer team to keep its runtime up to date and provide adequate test fixtures. Frequent dependency bumps with Polkadot releases would be beneficial for interoperability and could be streamlined with other system chains but that will not be a duty of fellowship. Whenever possible, all system chains could be upgraded jointly (including Encointer) with a batch referendum. @@ -3009,17 +7185,17 @@ To mitigate this, we propose preventing the market from closing at the ope Encointer will publish all its crates crates.io Encointer does not carry out external auditing of its runtime nor pallets. It would be beneficial but not a requirement from our side if Encointer could join the auditing process of other system chains. -Drawbacks +Drawbacks Other than all other system chains, development and maintenance of the Encointer Network is mainly financed by the KSM Treasury and possibly the DOT Treasury in the future. Encointer is dedicated to maintaining its network and runtime code for as long as possible, but there is a dependency on funding which is not in the hands of the fellowship. The only risk in the context of funding, however, is that the Encointer runtime will see less frequent updates if there's less funding. -Testing, Security, and Privacy +Testing, Security, and Privacy No changes to the existing system are proposed. Only changes to how maintenance is organized. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility No changes -Prior Art and References +Prior Art and References Existing Encointer runtime repo -Unresolved Questions +Unresolved Questions None identified -Future Directions and Related Material +Future Directions and Related Material More info on Encointer: encointer.org (source) Table of Contents @@ -3939,11 +8115,11 @@ other privacy-enhancing mechanisms to address this concern. AuthorsJoe Petrowski, Gavin Wood -Summary +Summary The Relay Chain contains most of the core logic for the Polkadot network. While this was necessary prior to the launch of parachains and development of XCM, most of this logic can exist in parachains. This is a proposal to migrate several subsystems into system parachains. -Motivation +Motivation Polkadot's scaling approach allows many distinct state machines (known generally as parachains) to operate with common guarantees about the validity and security of their state transitions. Polkadot provides these common guarantees by executing the state transitions on a strict subset (a backing @@ -3955,13 +8131,13 @@ blockspace) to the network. By minimising state transition logic on the Relay Chain by migrating it into "system chains" -- a set of parachains that, with the Relay Chain, make up the Polkadot protocol -- the Polkadot Ubiquitous Computer can maximise its primary offering: secure blockspace. -Stakeholders +Stakeholders Parachains that interact with affected logic on the Relay Chain; Core protocol and XCM format developers; Tooling, block explorer, and UI developers. -Explanation +Explanation The following pallets and subsystems are good candidates to migrate from the Relay Chain: Identity @@ -4107,36 +8283,36 @@ sensible to rehearse a migration. Staking is the subsystem most constrained by PoV limits. Ensuring that elections, payouts, session changes, offences/slashes, etc. work in a parachain on Kusama -- with its larger validator set -- will give confidence to the chain's robustness on Polkadot. -Drawbacks +Drawbacks These subsystems will have reduced resources in cores than on the Relay Chain. Staking in particular may require some optimizations to deal with constraints. -Testing, Security, and Privacy +Testing, Security, and Privacy Standard audit/review requirements apply. More powerful multi-chain integration test tools would be useful in developement. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility Describe the impact of the proposal on the exposed functionality of Polkadot. -Performance +Performance This is an optimization. The removal of public/user transactions on the Relay Chain ensures that its primary resources are allocated to system performance. -Ergonomics +Ergonomics This proposal alters very little for coretime users (e.g. parachain developers). Application developers will need to interact with multiple chains, making ergonomic light client tools particularly important for application development. For existing parachains that interact with these subsystems, they will need to configure their runtimes to recognize the new locations in the network. -Compatibility +Compatibility Implementing this proposal will require some changes to pallet APIs and/or a pub-sub protocol. Application developers will need to interact with multiple chains in the network. -Prior Art and References +Prior Art and References Transactionless Relay-chain Moving Staking off the Relay Chain -Unresolved Questions +Unresolved Questions There remain some implementation questions, like how to use balances for both Staking and Governance. See, for example, Moving Staking off the Relay Chain. -Future Directions and Related Material +Future Directions and Related Material Ideally the Relay Chain becomes transactionless, such that not even balances are represented there. With Staking and Governance off the Relay Chain, this is not an unreasonable next step. With Identity on Polkadot, Kusama may opt to drop its People Chain. @@ -4171,13 +8347,13 @@ With Staking and Governance off the Relay Chain, this is not an unreasonable nex AuthorsVedhavyas Singareddi -Summary +Summary At the moment, we have system_version field on RuntimeVersion that derives which state version is used for the Storage. We have a use case where we want extrinsics root is derived using StateVersion::V1. Without defining a new field under RuntimeVersion, we would like to propose adding system_version that can be used to derive both storage and extrinsic state version. -Motivation +Motivation Since the extrinsic state version is always StateVersion::V0, deriving extrinsic root requires full extrinsic data. This would be problematic when we need to verify the extrinsics root if the extrinsic sizes are bigger. This problem is further explored in https://github.com/polkadot-fellows/RFCs/issues/19 @@ -4189,11 +8365,11 @@ One of the main challenge here is some extrinsics could be big enough that this included in the Consensus block due to Block's weight restriction. If the extrinsic root is derived using StateVersion::V1, then we do not need to pass the full extrinsic data but rather at maximum, 32 byte of extrinsic data. -Stakeholders +Stakeholders Technical Fellowship, in its role of maintaining system runtimes. -Explanation +Explanation In order to use project specific StateVersion for extrinsic roots, we proposed an implementation that introduced parameter to frame_system::Config but that unfortunately did not feel correct. @@ -4219,26 +8395,26 @@ pub const VERSION: RuntimeVersion = RuntimeVersion { system_version: 1, }; }
1. Multi-Block-Migrations: The runtime is being put into lock-down mode for the duration of the migration process by returning OnlyInherents from initialize_block. This ensures that no user provided transaction can interfere with the migration process. It is absolutely necessary to ensure this, otherwise a transaction could call into un-migrated storage and violate storage invariants.
OnlyInherents
initialize_block
2. poll is possible by using apply_extrinsic as entry-point and not hindered by this approach. It would not be possible to use a pallet inherent like System::last_inherent to achieve this for two reasons: First is that pallets do not have access to AllPalletsWithSystem which is required to invoke the poll hook on all pallets. Second is that the runtime does currently not enforce an order of inherents.
apply_extrinsic
System::last_inherent
3. System::PostInherents can be done in the same manner as poll.
The previous drawback of cementing the order of inherents has been addressed and removed by redesigning the approach. No further drawbacks have been identified thus far.
The new logic of initialize_block can be tested by checking that the block-builder will skip transactions when OnlyInherents is returned.
Security: n/a
Privacy: n/a
The performance overhead is minimal in the sense that no clutter was added after fulfilling the requirements. The only performance difference is that initialize_block also returns an enum that needs to be passed through the WASM boundary. This should be negligible.
The new interface allows for more extensible runtime logic. In the future, this will be utilized for multi-block-migrations which should be a huge ergonomic advantage for parachain developers.
The advice here is OPTIONAL and outside of the RFC. To not degrade user experience, it is recommended to ensure that an updated node can still import historic blocks.
The RFC is currently being implemented in polkadot-sdk#1781 (formerly substrate#14275). Related issues and merge requests:
Please suggest a better name for BlockExecutiveMode. We already tried: RuntimeExecutiveMode, ExtrinsicInclusionMode. The names of the modes Normal and Minimal were also called AllExtrinsics and OnlyInherents, so if you have naming preferences; please post them. => renamed to ExtrinsicInclusionMode
BlockExecutiveMode
RuntimeExecutiveMode
Normal
Minimal
AllExtrinsics
Is post_inherents more consistent instead of last_inherent? Then we should change it. => renamed to last_inherent
post_inherents
last_inherent
The long-term future here is to move the block building logic into the runtime. Currently there is a tight dance between the block author and the runtime; the author has to call into different runtime functions in quick succession and exact order. Any misstep causes the block to be invalid. This can be unified and simplified by moving both parts into the runtime.
This RFC proposes a set of changes to the parachain lock mechanism. The goal is to allow a parachain manager to self-service the parachain without root track governance action.
This is achieved by remove existing lock conditions and only lock a parachain when:
The manager of a parachain has permission to manage the parachain when the parachain is unlocked. Parachains are by default locked when onboarded to a slot. This requires the parachain wasm/genesis must be valid, otherwise a root track governance action on relaychain is required to update the parachain.
The current reliance on root track governance actions for managing parachains can be time-consuming and burdensome. This RFC aims to address this technical difficulty by allowing parachain managers to take self-service actions, rather than relying on general public voting.
The key scenarios this RFC seeks to improve are:
One way to perform lease renewal for a parachain is by doing a least swap with another parachain with a longer lease. This requires the other parachain must be operational and able to perform XCM transact call into relaychain to dispatch the swap call. Combined with the overhead of setting up a new parachain, this is an time consuming and expensive process. Ideally, the parachain manager should be able to perform the lease swap call without having a running parachain2.
A parachain can either be locked or unlocked3. With parachain locked, the parachain manager does not have any privileges. With parachain unlocked, the parachain manager can perform following actions with the paras_registrar pallet:
paras_registrar
Parachain locks are designed in such way to ensure the decentralization of parachains. If parachains are not locked when it should be, it could introduce centralization risk for new parachains.
For example, one possible scenario is that a collective may decide to launch a parachain fully decentralized. However, if the parachain is unable to produce block, the parachain manager will be able to replace the wasm and genesis without the consent of the collective.
It is considered this risk is tolerable as it requires the wasm/genesis to be invalid at first place. It is not yet practically possible to develop a parachain without any centralized risk currently.
Another case is that a parachain team may decide to use crowdloan to help secure a slot lease. Previously, creating a crowdloan will lock a parachain. This means crowdloan participants will know exactly the genesis of the parachain for the crowdloan they are participating. However, this actually providers little assurance to crowdloan participants. For example, if the genesis block is determined before a crowdloan is started, it is not possible to have onchain mechanism to enforce reward distributions for crowdloan participants. They always have to rely on the parachain team to fulfill the promise after the parachain is alive.
Existing operational parachains will not be impacted.
An audit maybe required to ensure the implementation does not introduce unwanted side effects.
There is no privacy related concerns.
This RFC should improve the developer experiences for new and existing parachain teams
This RFC is fully compatibility with existing interfaces.
None at this stage.
This RFC is only intended to be a short term solution. Slots will be removed in future and lock mechanism is likely going to be replaced with a more generalized parachain manage & recovery system in future. Therefore long term impacts of this RFC are not considered.
https://github.com/paritytech/cumulus/issues/377 @@ -2826,11 +7002,11 @@ This can be unified and simplified by moving both parts into the runtime.
This document proposes a restructuring of the bulk markets in Polkadot's coretime allocation system to improve efficiency and fairness. The proposal suggests splitting the BULK_PERIOD into three consecutive phases: MARKET_PERIOD, RENEWAL_PERIOD, and SETTLEMENT_PERIOD. This structure enables market-driven price discovery through a clearing-price Dutch auction, followed by renewal offers during the RENEWAL_PERIOD.
BULK_PERIOD
MARKET_PERIOD
RENEWAL_PERIOD
SETTLEMENT_PERIOD
With all coretime consumers paying a unified price, we propose removing all liquidity restrictions on cores purchased either during the initial market phase or renewed during the renewal phase. This allows a meaningful SETTLEMENT_PERIOD, during which final agreements and deals between coretime consumers can be orchestrated on the social layer—complementing the agility this system seeks to establish.
In the new design, we obtain a uniform price, the clearing_price, which anchors new entrants and current tenants. To complement market-based price discovery, the design includes a dynamic reserve price adjustment mechanism based on actual core consumption. Together, these two components ensure robust price discovery while mitigating price collapse in cases of slight underutilization or collusive behavior.
clearing_price
After exposing the initial system introduced in RFC-1 to real-world conditions, several weaknesses have become apparent. These lie especially in the fact that cores captured at very low prices are removed from the open market and can effectively be retained indefinitely, as renewal costs are minimal. The key issue here is the absence of price anchoring, which results in two divergent price paths: one for the initial purchase on the open market, and another fully deterministic one via the renewal bump mechanism.
This proposal addresses these issues by anchoring all prices to a value derived from the market, while still preserving necessary privileges for current coretime consumers. The goal is to produce robust results across varying demand conditions (low, high, or volatile).
In particular, this proposal introduces the following key changes:
The premise of this proposal is to offer a straightforward design that discovers the price of coretime within a period as a clearing_price. Long-term coretime holders still retain the privilege to keep their cores if they can pay the price discovered by the market (with some premium for that privilege). The proposed model aims to strike a balance between leveraging market forces for allocation while operating within defined bounds. In particular, prices are capped within a BULK_PERIOD, which gives some certainty about prices to existing teams. It must be noted, however, that under high demand, prices could increase exponentially between multiple market cycles. This is a necessary feature to ensure proper price discovery and efficient coretime allocation.
Ultimately, the framework proposed here seeks to adhere to all requirements originally stated in RFC-1.
The BULK_PERIOD has been restructured into two primary segments: the MARKET_PERIOD and the RENEWAL_PERIOD, along with an auxiliarySETTLEMENT_PERIOD. The latter does not require any active participation from the coretime system chain except to simply execute transfers of ownership between market participants. A significant departure from the current design lies in the timing of renewals, which now occur after the market phase. This adjustment aims to harmonize renewal prices with their market counterparts, ensuring a more consistent and equitable pricing model.
During the market period, core sales are conducted through a well-established clearing-price Dutch auction that features a reserve_price. Since the auction format is a descending clock, the starting price is initialized at the opening_price. The price then descends linearly over the duration of the MARKET_PERIOD toward the reserve_price, which serves as the minimum price for coretime within that period.
reserve_price
opening_price
ope -Prior Art and References +Prior Art and References This RFC builds extensively on the available ideas put forward in RFC-1. Additionally, I want to express a special thanks to Samuel Haefner, Shahar Dobzinski, and Alistair Stewart for fruitful discussions and helping me structure my thoughts. (source) @@ -2988,19 +7164,19 @@ To mitigate this, we propose preventing the market from closing at the ope Authors@brenzi for Encointer Association, 8000 Zurich, Switzerland -Summary +Summary Encointer is a system chain on Kusama since Jan 2022 and has been developed and maintained by the Encointer association. This RFC proposes to treat Encointer like any other system chain and include it in the fellowship repo with this PR. -Motivation +Motivation Encointer does not seek to be in control of its runtime repository. As a decentralized system, the fellowship has a more suitable structure to maintain a system chain runtime repo than the Encointer association does. Also, Encointer aims to update its runtime in batches with other system chains in order to have consistency for interoperability across system chains. -Stakeholders +Stakeholders Fellowship: Will continue to take upon them the review and auditing work for the Encointer runtime, but the process is streamlined with other system chains and therefore less time-consuming compared to the separate repo and CI process we currently have. Kusama Network: Tokenholders can easily see the changes of all system chains in one place. Encointer Association: Further decentralization of the Encointer Network necessities like devops. Encointer devs: Being able to work directly in the Fellowship runtimes repo to streamline and synergize with other developers. -Explanation +Explanation Our PR has all details about our runtime and how we would move it into the fellowship repo. Noteworthy: All Encointer-specific pallets will still be located in encointer's repo for the time being: https://github.com/encointer/pallets It will still be the duty of the Encointer team to keep its runtime up to date and provide adequate test fixtures. Frequent dependency bumps with Polkadot releases would be beneficial for interoperability and could be streamlined with other system chains but that will not be a duty of fellowship. Whenever possible, all system chains could be upgraded jointly (including Encointer) with a batch referendum. @@ -3009,17 +7185,17 @@ To mitigate this, we propose preventing the market from closing at the ope Encointer will publish all its crates crates.io Encointer does not carry out external auditing of its runtime nor pallets. It would be beneficial but not a requirement from our side if Encointer could join the auditing process of other system chains. -Drawbacks +Drawbacks Other than all other system chains, development and maintenance of the Encointer Network is mainly financed by the KSM Treasury and possibly the DOT Treasury in the future. Encointer is dedicated to maintaining its network and runtime code for as long as possible, but there is a dependency on funding which is not in the hands of the fellowship. The only risk in the context of funding, however, is that the Encointer runtime will see less frequent updates if there's less funding. -Testing, Security, and Privacy +Testing, Security, and Privacy No changes to the existing system are proposed. Only changes to how maintenance is organized. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility No changes -Prior Art and References +Prior Art and References Existing Encointer runtime repo -Unresolved Questions +Unresolved Questions None identified -Future Directions and Related Material +Future Directions and Related Material More info on Encointer: encointer.org (source) Table of Contents @@ -3939,11 +8115,11 @@ other privacy-enhancing mechanisms to address this concern. AuthorsJoe Petrowski, Gavin Wood -Summary +Summary The Relay Chain contains most of the core logic for the Polkadot network. While this was necessary prior to the launch of parachains and development of XCM, most of this logic can exist in parachains. This is a proposal to migrate several subsystems into system parachains. -Motivation +Motivation Polkadot's scaling approach allows many distinct state machines (known generally as parachains) to operate with common guarantees about the validity and security of their state transitions. Polkadot provides these common guarantees by executing the state transitions on a strict subset (a backing @@ -3955,13 +8131,13 @@ blockspace) to the network. By minimising state transition logic on the Relay Chain by migrating it into "system chains" -- a set of parachains that, with the Relay Chain, make up the Polkadot protocol -- the Polkadot Ubiquitous Computer can maximise its primary offering: secure blockspace. -Stakeholders +Stakeholders Parachains that interact with affected logic on the Relay Chain; Core protocol and XCM format developers; Tooling, block explorer, and UI developers. -Explanation +Explanation The following pallets and subsystems are good candidates to migrate from the Relay Chain: Identity @@ -4107,36 +8283,36 @@ sensible to rehearse a migration. Staking is the subsystem most constrained by PoV limits. Ensuring that elections, payouts, session changes, offences/slashes, etc. work in a parachain on Kusama -- with its larger validator set -- will give confidence to the chain's robustness on Polkadot. -Drawbacks +Drawbacks These subsystems will have reduced resources in cores than on the Relay Chain. Staking in particular may require some optimizations to deal with constraints. -Testing, Security, and Privacy +Testing, Security, and Privacy Standard audit/review requirements apply. More powerful multi-chain integration test tools would be useful in developement. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility Describe the impact of the proposal on the exposed functionality of Polkadot. -Performance +Performance This is an optimization. The removal of public/user transactions on the Relay Chain ensures that its primary resources are allocated to system performance. -Ergonomics +Ergonomics This proposal alters very little for coretime users (e.g. parachain developers). Application developers will need to interact with multiple chains, making ergonomic light client tools particularly important for application development. For existing parachains that interact with these subsystems, they will need to configure their runtimes to recognize the new locations in the network. -Compatibility +Compatibility Implementing this proposal will require some changes to pallet APIs and/or a pub-sub protocol. Application developers will need to interact with multiple chains in the network. -Prior Art and References +Prior Art and References Transactionless Relay-chain Moving Staking off the Relay Chain -Unresolved Questions +Unresolved Questions There remain some implementation questions, like how to use balances for both Staking and Governance. See, for example, Moving Staking off the Relay Chain. -Future Directions and Related Material +Future Directions and Related Material Ideally the Relay Chain becomes transactionless, such that not even balances are represented there. With Staking and Governance off the Relay Chain, this is not an unreasonable next step. With Identity on Polkadot, Kusama may opt to drop its People Chain. @@ -4171,13 +8347,13 @@ With Staking and Governance off the Relay Chain, this is not an unreasonable nex AuthorsVedhavyas Singareddi -Summary +Summary At the moment, we have system_version field on RuntimeVersion that derives which state version is used for the Storage. We have a use case where we want extrinsics root is derived using StateVersion::V1. Without defining a new field under RuntimeVersion, we would like to propose adding system_version that can be used to derive both storage and extrinsic state version. -Motivation +Motivation Since the extrinsic state version is always StateVersion::V0, deriving extrinsic root requires full extrinsic data. This would be problematic when we need to verify the extrinsics root if the extrinsic sizes are bigger. This problem is further explored in https://github.com/polkadot-fellows/RFCs/issues/19 @@ -4189,11 +8365,11 @@ One of the main challenge here is some extrinsics could be big enough that this included in the Consensus block due to Block's weight restriction. If the extrinsic root is derived using StateVersion::V1, then we do not need to pass the full extrinsic data but rather at maximum, 32 byte of extrinsic data. -Stakeholders +Stakeholders Technical Fellowship, in its role of maintaining system runtimes. -Explanation +Explanation In order to use project specific StateVersion for extrinsic roots, we proposed an implementation that introduced parameter to frame_system::Config but that unfortunately did not feel correct. @@ -4219,26 +8395,26 @@ pub const VERSION: RuntimeVersion = RuntimeVersion { system_version: 1, }; }
This RFC builds extensively on the available ideas put forward in RFC-1.
Additionally, I want to express a special thanks to Samuel Haefner, Shahar Dobzinski, and Alistair Stewart for fruitful discussions and helping me structure my thoughts.
ope Authors@brenzi for Encointer Association, 8000 Zurich, Switzerland -Summary +Summary Encointer is a system chain on Kusama since Jan 2022 and has been developed and maintained by the Encointer association. This RFC proposes to treat Encointer like any other system chain and include it in the fellowship repo with this PR. -Motivation +Motivation Encointer does not seek to be in control of its runtime repository. As a decentralized system, the fellowship has a more suitable structure to maintain a system chain runtime repo than the Encointer association does. Also, Encointer aims to update its runtime in batches with other system chains in order to have consistency for interoperability across system chains. -Stakeholders +Stakeholders Fellowship: Will continue to take upon them the review and auditing work for the Encointer runtime, but the process is streamlined with other system chains and therefore less time-consuming compared to the separate repo and CI process we currently have. Kusama Network: Tokenholders can easily see the changes of all system chains in one place. Encointer Association: Further decentralization of the Encointer Network necessities like devops. Encointer devs: Being able to work directly in the Fellowship runtimes repo to streamline and synergize with other developers. -Explanation +Explanation Our PR has all details about our runtime and how we would move it into the fellowship repo. Noteworthy: All Encointer-specific pallets will still be located in encointer's repo for the time being: https://github.com/encointer/pallets It will still be the duty of the Encointer team to keep its runtime up to date and provide adequate test fixtures. Frequent dependency bumps with Polkadot releases would be beneficial for interoperability and could be streamlined with other system chains but that will not be a duty of fellowship. Whenever possible, all system chains could be upgraded jointly (including Encointer) with a batch referendum. @@ -3009,17 +7185,17 @@ To mitigate this, we propose preventing the market from closing at the ope Encointer will publish all its crates crates.io Encointer does not carry out external auditing of its runtime nor pallets. It would be beneficial but not a requirement from our side if Encointer could join the auditing process of other system chains. -Drawbacks +Drawbacks Other than all other system chains, development and maintenance of the Encointer Network is mainly financed by the KSM Treasury and possibly the DOT Treasury in the future. Encointer is dedicated to maintaining its network and runtime code for as long as possible, but there is a dependency on funding which is not in the hands of the fellowship. The only risk in the context of funding, however, is that the Encointer runtime will see less frequent updates if there's less funding. -Testing, Security, and Privacy +Testing, Security, and Privacy No changes to the existing system are proposed. Only changes to how maintenance is organized. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility No changes -Prior Art and References +Prior Art and References Existing Encointer runtime repo -Unresolved Questions +Unresolved Questions None identified -Future Directions and Related Material +Future Directions and Related Material More info on Encointer: encointer.org (source) Table of Contents @@ -3939,11 +8115,11 @@ other privacy-enhancing mechanisms to address this concern. AuthorsJoe Petrowski, Gavin Wood -Summary +Summary The Relay Chain contains most of the core logic for the Polkadot network. While this was necessary prior to the launch of parachains and development of XCM, most of this logic can exist in parachains. This is a proposal to migrate several subsystems into system parachains. -Motivation +Motivation Polkadot's scaling approach allows many distinct state machines (known generally as parachains) to operate with common guarantees about the validity and security of their state transitions. Polkadot provides these common guarantees by executing the state transitions on a strict subset (a backing @@ -3955,13 +8131,13 @@ blockspace) to the network. By minimising state transition logic on the Relay Chain by migrating it into "system chains" -- a set of parachains that, with the Relay Chain, make up the Polkadot protocol -- the Polkadot Ubiquitous Computer can maximise its primary offering: secure blockspace. -Stakeholders +Stakeholders Parachains that interact with affected logic on the Relay Chain; Core protocol and XCM format developers; Tooling, block explorer, and UI developers. -Explanation +Explanation The following pallets and subsystems are good candidates to migrate from the Relay Chain: Identity @@ -4107,36 +8283,36 @@ sensible to rehearse a migration. Staking is the subsystem most constrained by PoV limits. Ensuring that elections, payouts, session changes, offences/slashes, etc. work in a parachain on Kusama -- with its larger validator set -- will give confidence to the chain's robustness on Polkadot. -Drawbacks +Drawbacks These subsystems will have reduced resources in cores than on the Relay Chain. Staking in particular may require some optimizations to deal with constraints. -Testing, Security, and Privacy +Testing, Security, and Privacy Standard audit/review requirements apply. More powerful multi-chain integration test tools would be useful in developement. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility Describe the impact of the proposal on the exposed functionality of Polkadot. -Performance +Performance This is an optimization. The removal of public/user transactions on the Relay Chain ensures that its primary resources are allocated to system performance. -Ergonomics +Ergonomics This proposal alters very little for coretime users (e.g. parachain developers). Application developers will need to interact with multiple chains, making ergonomic light client tools particularly important for application development. For existing parachains that interact with these subsystems, they will need to configure their runtimes to recognize the new locations in the network. -Compatibility +Compatibility Implementing this proposal will require some changes to pallet APIs and/or a pub-sub protocol. Application developers will need to interact with multiple chains in the network. -Prior Art and References +Prior Art and References Transactionless Relay-chain Moving Staking off the Relay Chain -Unresolved Questions +Unresolved Questions There remain some implementation questions, like how to use balances for both Staking and Governance. See, for example, Moving Staking off the Relay Chain. -Future Directions and Related Material +Future Directions and Related Material Ideally the Relay Chain becomes transactionless, such that not even balances are represented there. With Staking and Governance off the Relay Chain, this is not an unreasonable next step. With Identity on Polkadot, Kusama may opt to drop its People Chain. @@ -4171,13 +8347,13 @@ With Staking and Governance off the Relay Chain, this is not an unreasonable nex AuthorsVedhavyas Singareddi -Summary +Summary At the moment, we have system_version field on RuntimeVersion that derives which state version is used for the Storage. We have a use case where we want extrinsics root is derived using StateVersion::V1. Without defining a new field under RuntimeVersion, we would like to propose adding system_version that can be used to derive both storage and extrinsic state version. -Motivation +Motivation Since the extrinsic state version is always StateVersion::V0, deriving extrinsic root requires full extrinsic data. This would be problematic when we need to verify the extrinsics root if the extrinsic sizes are bigger. This problem is further explored in https://github.com/polkadot-fellows/RFCs/issues/19 @@ -4189,11 +8365,11 @@ One of the main challenge here is some extrinsics could be big enough that this included in the Consensus block due to Block's weight restriction. If the extrinsic root is derived using StateVersion::V1, then we do not need to pass the full extrinsic data but rather at maximum, 32 byte of extrinsic data. -Stakeholders +Stakeholders Technical Fellowship, in its role of maintaining system runtimes. -Explanation +Explanation In order to use project specific StateVersion for extrinsic roots, we proposed an implementation that introduced parameter to frame_system::Config but that unfortunately did not feel correct. @@ -4219,26 +8395,26 @@ pub const VERSION: RuntimeVersion = RuntimeVersion { system_version: 1, }; }
Encointer is a system chain on Kusama since Jan 2022 and has been developed and maintained by the Encointer association. This RFC proposes to treat Encointer like any other system chain and include it in the fellowship repo with this PR.
Encointer does not seek to be in control of its runtime repository. As a decentralized system, the fellowship has a more suitable structure to maintain a system chain runtime repo than the Encointer association does.
Also, Encointer aims to update its runtime in batches with other system chains in order to have consistency for interoperability across system chains.
Our PR has all details about our runtime and how we would move it into the fellowship repo.
Noteworthy: All Encointer-specific pallets will still be located in encointer's repo for the time being: https://github.com/encointer/pallets
It will still be the duty of the Encointer team to keep its runtime up to date and provide adequate test fixtures. Frequent dependency bumps with Polkadot releases would be beneficial for interoperability and could be streamlined with other system chains but that will not be a duty of fellowship. Whenever possible, all system chains could be upgraded jointly (including Encointer) with a batch referendum.
ope Encointer will publish all its crates crates.io Encointer does not carry out external auditing of its runtime nor pallets. It would be beneficial but not a requirement from our side if Encointer could join the auditing process of other system chains. -Drawbacks +Drawbacks Other than all other system chains, development and maintenance of the Encointer Network is mainly financed by the KSM Treasury and possibly the DOT Treasury in the future. Encointer is dedicated to maintaining its network and runtime code for as long as possible, but there is a dependency on funding which is not in the hands of the fellowship. The only risk in the context of funding, however, is that the Encointer runtime will see less frequent updates if there's less funding. -Testing, Security, and Privacy +Testing, Security, and Privacy No changes to the existing system are proposed. Only changes to how maintenance is organized. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility No changes -Prior Art and References +Prior Art and References Existing Encointer runtime repo -Unresolved Questions +Unresolved Questions None identified -Future Directions and Related Material +Future Directions and Related Material More info on Encointer: encointer.org (source) Table of Contents @@ -3939,11 +8115,11 @@ other privacy-enhancing mechanisms to address this concern. AuthorsJoe Petrowski, Gavin Wood -Summary +Summary The Relay Chain contains most of the core logic for the Polkadot network. While this was necessary prior to the launch of parachains and development of XCM, most of this logic can exist in parachains. This is a proposal to migrate several subsystems into system parachains. -Motivation +Motivation Polkadot's scaling approach allows many distinct state machines (known generally as parachains) to operate with common guarantees about the validity and security of their state transitions. Polkadot provides these common guarantees by executing the state transitions on a strict subset (a backing @@ -3955,13 +8131,13 @@ blockspace) to the network. By minimising state transition logic on the Relay Chain by migrating it into "system chains" -- a set of parachains that, with the Relay Chain, make up the Polkadot protocol -- the Polkadot Ubiquitous Computer can maximise its primary offering: secure blockspace. -Stakeholders +Stakeholders Parachains that interact with affected logic on the Relay Chain; Core protocol and XCM format developers; Tooling, block explorer, and UI developers. -Explanation +Explanation The following pallets and subsystems are good candidates to migrate from the Relay Chain: Identity @@ -4107,36 +8283,36 @@ sensible to rehearse a migration. Staking is the subsystem most constrained by PoV limits. Ensuring that elections, payouts, session changes, offences/slashes, etc. work in a parachain on Kusama -- with its larger validator set -- will give confidence to the chain's robustness on Polkadot. -Drawbacks +Drawbacks These subsystems will have reduced resources in cores than on the Relay Chain. Staking in particular may require some optimizations to deal with constraints. -Testing, Security, and Privacy +Testing, Security, and Privacy Standard audit/review requirements apply. More powerful multi-chain integration test tools would be useful in developement. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility Describe the impact of the proposal on the exposed functionality of Polkadot. -Performance +Performance This is an optimization. The removal of public/user transactions on the Relay Chain ensures that its primary resources are allocated to system performance. -Ergonomics +Ergonomics This proposal alters very little for coretime users (e.g. parachain developers). Application developers will need to interact with multiple chains, making ergonomic light client tools particularly important for application development. For existing parachains that interact with these subsystems, they will need to configure their runtimes to recognize the new locations in the network. -Compatibility +Compatibility Implementing this proposal will require some changes to pallet APIs and/or a pub-sub protocol. Application developers will need to interact with multiple chains in the network. -Prior Art and References +Prior Art and References Transactionless Relay-chain Moving Staking off the Relay Chain -Unresolved Questions +Unresolved Questions There remain some implementation questions, like how to use balances for both Staking and Governance. See, for example, Moving Staking off the Relay Chain. -Future Directions and Related Material +Future Directions and Related Material Ideally the Relay Chain becomes transactionless, such that not even balances are represented there. With Staking and Governance off the Relay Chain, this is not an unreasonable next step. With Identity on Polkadot, Kusama may opt to drop its People Chain. @@ -4171,13 +8347,13 @@ With Staking and Governance off the Relay Chain, this is not an unreasonable nex AuthorsVedhavyas Singareddi -Summary +Summary At the moment, we have system_version field on RuntimeVersion that derives which state version is used for the Storage. We have a use case where we want extrinsics root is derived using StateVersion::V1. Without defining a new field under RuntimeVersion, we would like to propose adding system_version that can be used to derive both storage and extrinsic state version. -Motivation +Motivation Since the extrinsic state version is always StateVersion::V0, deriving extrinsic root requires full extrinsic data. This would be problematic when we need to verify the extrinsics root if the extrinsic sizes are bigger. This problem is further explored in https://github.com/polkadot-fellows/RFCs/issues/19 @@ -4189,11 +8365,11 @@ One of the main challenge here is some extrinsics could be big enough that this included in the Consensus block due to Block's weight restriction. If the extrinsic root is derived using StateVersion::V1, then we do not need to pass the full extrinsic data but rather at maximum, 32 byte of extrinsic data. -Stakeholders +Stakeholders Technical Fellowship, in its role of maintaining system runtimes. -Explanation +Explanation In order to use project specific StateVersion for extrinsic roots, we proposed an implementation that introduced parameter to frame_system::Config but that unfortunately did not feel correct. @@ -4219,26 +8395,26 @@ pub const VERSION: RuntimeVersion = RuntimeVersion { system_version: 1, }; }
Other than all other system chains, development and maintenance of the Encointer Network is mainly financed by the KSM Treasury and possibly the DOT Treasury in the future. Encointer is dedicated to maintaining its network and runtime code for as long as possible, but there is a dependency on funding which is not in the hands of the fellowship. The only risk in the context of funding, however, is that the Encointer runtime will see less frequent updates if there's less funding.
No changes to the existing system are proposed. Only changes to how maintenance is organized.
No changes
Existing Encointer runtime repo
None identified
More info on Encointer: encointer.org
The Relay Chain contains most of the core logic for the Polkadot network. While this was necessary prior to the launch of parachains and development of XCM, most of this logic can exist in parachains. This is a proposal to migrate several subsystems into system parachains.
Polkadot's scaling approach allows many distinct state machines (known generally as parachains) to operate with common guarantees about the validity and security of their state transitions. Polkadot provides these common guarantees by executing the state transitions on a strict subset (a backing @@ -3955,13 +8131,13 @@ blockspace) to the network.
By minimising state transition logic on the Relay Chain by migrating it into "system chains" -- a set of parachains that, with the Relay Chain, make up the Polkadot protocol -- the Polkadot Ubiquitous Computer can maximise its primary offering: secure blockspace.
The following pallets and subsystems are good candidates to migrate from the Relay Chain:
These subsystems will have reduced resources in cores than on the Relay Chain. Staking in particular may require some optimizations to deal with constraints.
Standard audit/review requirements apply. More powerful multi-chain integration test tools would be useful in developement.
This is an optimization. The removal of public/user transactions on the Relay Chain ensures that its primary resources are allocated to system performance.
This proposal alters very little for coretime users (e.g. parachain developers). Application developers will need to interact with multiple chains, making ergonomic light client tools particularly important for application development.
For existing parachains that interact with these subsystems, they will need to configure their runtimes to recognize the new locations in the network.
Implementing this proposal will require some changes to pallet APIs and/or a pub-sub protocol. Application developers will need to interact with multiple chains in the network.
There remain some implementation questions, like how to use balances for both Staking and Governance. See, for example, Moving Staking off the Relay Chain.
Ideally the Relay Chain becomes transactionless, such that not even balances are represented there. With Staking and Governance off the Relay Chain, this is not an unreasonable next step.
With Identity on Polkadot, Kusama may opt to drop its People Chain.
At the moment, we have system_version field on RuntimeVersion that derives which state version is used for the Storage. We have a use case where we want extrinsics root is derived using StateVersion::V1. Without defining a new field under RuntimeVersion, we would like to propose adding system_version that can be used to derive both storage and extrinsic state version.
system_version
RuntimeVersion
StateVersion::V1
Since the extrinsic state version is always StateVersion::V0, deriving extrinsic root requires full extrinsic data. This would be problematic when we need to verify the extrinsics root if the extrinsic sizes are bigger. This problem is further explored in https://github.com/polkadot-fellows/RFCs/issues/19
StateVersion::V0
In order to use project specific StateVersion for extrinsic roots, we proposed an implementation that introduced parameter to frame_system::Config but that unfortunately did not feel correct. @@ -4219,26 +8395,26 @@ pub const VERSION: RuntimeVersion = RuntimeVersion { system_version: 1, }; }
frame_system::Config
There should be no drawbacks as it would replace state_version with same behavior but documentation should be updated so that chains know which system_version to use.
state_version
AFAIK, should not have any impact on the security or privacy.
These changes should be compatible for existing chains if they use state_version value for system_verision.
system_verision
I do not believe there is any performance hit with this change.
This does not break any exposed Apis.
This change should not break any compatibility.
We proposed introducing a similar change by introducing a parameter to frame_system::Config but did not feel that is the correct way of introducing this change.
I do not have any specific questions about this change at the moment.
IMO, this change is pretty self-contained and there won't be any future work necessary.
This RFC proposes a new host function for parachains, storage_proof_size. It shall provide the size of the currently recorded storage proof to the runtime. Runtime authors can use the proof size to improve block utilization by retroactively reclaiming unused storage weight.
storage_proof_size
The number of extrinsics that are included in a parachain block is limited by two constraints: execution time and proof size. FRAME weights cover both concepts, and block-builders use them to decide how many extrinsics to include in a block. However, these weights are calculated ahead of time by benchmarking on a machine with reference hardware. The execution-time properties of the state-trie and its storage items are unknown at benchmarking time. Therefore, we make some assumptions about the state-trie:
These pessimistic assumptions lead to an overestimation of storage weight, negatively impacting block utilization on parachains.
In addition, the current model does not account for multiple accesses to the same storage items. While these repetitive accesses will not increase storage-proof size, the runtime-side weight monitoring will account for them multiple times. Since the proof size is completely opaque to the runtime, we can not implement retroactive storage weight correction.
A solution must provide a way for the runtime to track the exact storage-proof size consumed on a per-extrinsic basis.
This RFC proposes a new host function that exposes the storage-proof size to the runtime. As a result, runtimes can implement storage weight reclaiming mechanisms that improve block utilization.
This RFC proposes the following host function signature:
#![allow(unused)] @@ -4291,14 +8467,14 @@ is the correct way of introducing this change. fn ext_storage_proof_size_version_1() -> u64; }
The host function MUST return an unsigned 64-bit integer value representing the current proof size. In block-execution and block-import contexts, this function MUST return the current size of the proof. To achieve this, parachain node implementors need to enable proof recording for block imports. In other contexts, this function MUST return 18446744073709551615 (u64::MAX), which represents disabled proof recording.
Parachain nodes need to enable proof recording during block import to correctly implement the proposed host function. Benchmarking conducted with balance transfers has shown a performance reduction of around 0.6% when proof recording is enabled.
The host function proposed in this RFC allows parachain runtime developers to keep track of the proof size. Typical usage patterns would be to keep track of the overall proof size or the difference between subsequent calls to the host function.
This RFC proposes changing the current deposit requirements on the Polkadot and Kusama Asset Hub for creating an NFT collection, minting an individual NFT, and lowering its corresponding metadata and attribute deposits. The objective is to lower the barrier to entry for NFT creators, fostering a more inclusive and vibrant ecosystem while maintaining network integrity and preventing spam.
The current deposit of 10 DOT for collection creation (along with 0.01 DOT for item deposit and 0.2 DOT for metadata and attribute deposits) on the Polkadot Asset Hub and 0.1 KSM on Kusama Asset Hub presents a significant financial barrier for many NFT creators. By lowering the deposit @@ -4370,11 +8546,11 @@ introduced to storage and the size of corresponding values stored.
Further, it suggests a direction for a future of calculating deposits variably based on adoption and/or market conditions. There is a discussion on tradeoffs of setting deposits too high or too low.
deposit
Previous discussions have been held within the Polkadot Forum, with artists expressing their concerns about the deposit amounts.
This RFC proposes a revision of the deposit constants in the configuration of the NFTs pallet on the Polkadot Asset Hub. The new deposit amounts would be determined by a standard deposit formula.
As of v1.1.1, the Collection Deposit is 10 DOT and the Item Deposit is 0.01 DOT (see @@ -4459,7 +8635,7 @@ application to avoid sudden rate changes, as in:
where the constant a moves the inflection to lower or higher x values, the constant b adjusts the rate of the deposit increase, and the independent variable x is the number of collections or items, depending on application.
a
b
Modifying deposit requirements necessitates a balanced assessment of the potential drawbacks. Highlighted below are cogent points extracted from the discourse on the Polkadot Forum conversation, @@ -4488,22 +8664,22 @@ stakeholders wouldn't be much affected. As of date 9th January 2024 there are 42 Polkadot Asset Hub and 191 on Kusama Asset Hub with a relatively low volume.
As noted above, state bloat is a security concern. In the case of abuse, governance could adapt by increasing deposit rates and/or using forceDestroy on collections agreed to be spam.
forceDestroy
The primary performance consideration stems from the potential for state bloat due to increased activity from lower deposit requirements. It's vital to monitor and manage this to avoid any negative impact on the chain's performance. Strategies for mitigating state bloat, including efficient data management and periodic reviews of storage requirements, will be essential.
The proposed change aims to enhance the user experience for artists, traders, and utilizers of Kusama and Polkadot Asset Hubs, making Polkadot and Kusama more accessible and user-friendly.
The change does not impact compatibility as a redeposit function is already implemented.
redeposit
If this RFC is accepted, there should not be any unresolved questions regarding how to adapt the implementation of deposits for NFT collections.
Propose a way of permuting the availability chunk indices assigned to validators, in the context of recovering available data from systematic chunks, with the purpose of fairly distributing network bandwidth usage.
Currently, the ValidatorIndex is always identical to the ChunkIndex. Since the validator array is only shuffled once per session, naively using the ValidatorIndex as the ChunkIndex would pose an unreasonable stress on the first N/3 validators during an entire session, when favouring availability recovery from systematic chunks.
Relay chain node core developers.
An erasure coding algorithm is considered systematic if it preserves the original unencoded data as part of the resulting code. @@ -4759,7 +8935,7 @@ struct (added in https://github.com/paritytech/polkadot-sdk/pull/2177Configuration::set_node_feature extrinsic. Once the feature is enabled and new configuration is live, the validator->chunk mapping ceases to be a 1:1 mapping and systematic recovery may begin.
https://github.com/paritytech/polkadot-sdk/pull/2177Configuration::set_node_feature
core_index
CandidateReceipt
Extensive testing will be conducted - both automated and manual. This proposal doesn't affect security or privacy.
This is a necessary data availability optimisation, as reed-solomon erasure coding has proven to be a top consumer of CPU time in polkadot as we scale up the parachain block size and number of availability cores.
With this optimisation, preliminary performance results show that CPU time used for reed-solomon coding/decoding can be halved and total POV recovery time decrease by 80% for large POVs. See more here.
Not applicable.
This is a breaking change. See upgrade path section above. All validators and collators need to have upgraded their node versions before the feature will be enabled via a governance call.
See comments on the tracking issue and the in-progress PR
This enables future optimisations for the performance of availability recovery, such as retrieving batched systematic chunks from backers/approval-checkers.
This RFC proposes to changes the SessionKeys::generate_session_keys runtime api interface. This runtime api is used by validator operators to generate new session keys on a node. The public session keys are then registered manually on chain by the validator operator. Before this RFC it was not possible by the on chain logic to ensure that the account setting the public session keys is also in @@ -4873,7 +9049,7 @@ possession of the private session keys. To solve this the RFC proposes to pass t registration on chain to generate_session_keys. Further this RFC proposes to change the return value of the generate_session_keys function also to not only return the public session keys, but also the proof of ownership for the private session keys. The validator operator will then need to send the public session keys and the proof together when registering new session keys on chain.
SessionKeys::generate_session_keys
generate_session_keys
When submitting the new public session keys to the on chain logic there doesn't exist any verification of possession of the private session keys. This means that users can basically register any kind of public session keys on chain. While the on chain logic ensures that there are no duplicate keys, someone could try to prevent others from registering new session keys by setting them first. While this wouldn't bring @@ -4881,13 +9057,13 @@ the "attacker" any kind of advantage, more like disadvantages (potenti e.g. changing its session key in the event of a private session key leak.
After this RFC this kind of attack would not be possible anymore, because the on chain logic can verify that the sending account is in ownership of the private session keys.
We are first going to explain the proof format being used:
proof
#![allow(unused)] fn main() { @@ -4921,31 +9097,31 @@ actual exported function signature looks like: already gets the proof passed as Vec<u8>. This proof needs to be decoded to the actual Proof type as explained above. The proof and the SCALE encoded account_id of the sender are used to verify the ownership of the SessionKeys. -Drawbacks +Drawbacks Validator operators need to pass the their account id when rotating their session keys in a node. This will require updating some high level docs and making users familiar with the slightly changed ergonomics. -Testing, Security, and Privacy +Testing, Security, and Privacy Testing of the new changes only requires passing an appropriate owner for the current testing context. The changes to the proof generation and verification got audited to ensure they are correct. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance The session key generation is an offchain process and thus, doesn't influence the performance of the chain. Verifying the proof is done on chain as part of the transaction logic for setting the session keys. The verification of the proof is a signature verification number of individual session keys times. As setting the session keys is happening quite rarely, it should not influence the overall system performance. -Ergonomics +Ergonomics The interfaces have been optimized to make it as easy as possible to generate the ownership proof. -Compatibility +Compatibility Introduces a new version of the SessionKeys runtime api. Thus, nodes should be updated before a runtime is enacted that contains these changes otherwise they will fail to generate session keys. The RPC that exists around this runtime api needs to be updated to support passing the account id and for returning the ownership proof alongside the public session keys. UIs would need to be updated to support the new RPC and the changed on chain logic. -Prior Art and References +Prior Art and References None. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material Substrate implementation of the RFC. (source) Table of Contents @@ -4983,10 +9159,10 @@ and for returning the ownership proof alongside the public session keys. AuthorsJoe Petrowski, Gavin Wood -Summary +Summary The Fellowship Manifesto states that members should receive a monthly allowance on par with gross income in OECD countries. This RFC proposes concrete amounts. -Motivation +Motivation One motivation for the Technical Fellowship is to provide an incentive mechanism that can induct and retain technical talent for the continued progress of the network. In order for members to uphold their commitment to the network, they should receive support to @@ -4996,12 +9172,12 @@ on par with a full-time job. Providing a livable wage to those making such contr pragmatic to work full-time on Polkadot. Note: Goals of the Fellowship, expectations for each Dan, and conditions for promotion and demotion are all explained in the Manifesto. This RFC is only to propose concrete values for allowances. -Stakeholders +Stakeholders Fellowship members Polkadot Treasury -Explanation +Explanation This RFC proposes agreeing on salaries relative to a single level, the III Dan. As such, changes to the amount or asset used would only be on a single value, and all others would adjust relatively. A III Dan is someone whose contributions match the expectations of a full-time individual contributor. @@ -5061,19 +9237,19 @@ other hand, more people will likely join the Fellowship in the coming years. Updates Updates to these levels, whether relative ratios, the asset used, or the amount, shall be done via RFC. -Drawbacks +Drawbacks By not using DOT for payment, the protocol relies on the stability of other assets and the ability to acquire them. However, the asset of choice can be changed in the future. -Testing, Security, and Privacy +Testing, Security, and Privacy N/A. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance N/A -Ergonomics +Ergonomics N/A -Compatibility +Compatibility N/A -Prior Art and References +Prior Art and References The Polkadot Fellowship Manifesto @@ -5081,7 +9257,7 @@ Manifesto Indeed: Average Salary for Engineers, United States -Unresolved Questions +Unresolved Questions None at present. (source) Table of Contents @@ -5114,11 +9290,11 @@ States AuthorsPierre Krieger -Summary +Summary When two peers connect to each other, they open (amongst other things) a so-called "notifications protocol" substream dedicated to gossiping transactions to each other. Each notification on this substream currently consists in a SCALE-encoded Vec<Transaction> where Transaction is defined in the runtime. This RFC proposes to modify the format of the notification to become (Compact(1), Transaction). This maintains backwards compatibility, as this new format decodes as a Vec of length equal to 1. -Motivation +Motivation There exists three motivations behind this change: @@ -5131,9 +9307,9 @@ States It makes the implementation way more straight-forward by not having to repeat code related to back-pressure. See explanations below. -Stakeholders +Stakeholders Low-level developers. -Explanation +Explanation To give an example, if you send one notification with three transactions, the bytes that are sent on the wire are: concat( leb128(total-size-in-bytes-of-the-rest), @@ -5153,23 +9329,23 @@ A SCALE-compact encoded 1 is one byte of value 4. In o This is equivalent to forcing the Vec<Transaction> to always have a length of 1, and I expect the Substrate implementation to simply modify the sending side to add a for loop that sends one notification per item in the Vec. As explained in the motivation section, this allows extracting scale(transaction) items without having to know how to decode them. By "flattening" the two-steps hierarchy, an implementation only needs to back-pressure individual notifications rather than back-pressure notifications and transactions within notifications. -Drawbacks +Drawbacks This RFC chooses to maintain backwards compatibility at the cost of introducing a very small wart (the Compact(1)). An alternative could be to introduce a new version of the transactions notifications protocol that sends one Transaction per notification, but this is significantly more complicated to implement and can always be done later in case the Compact(1) is bothersome. -Testing, Security, and Privacy +Testing, Security, and Privacy Irrelevant. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance Irrelevant. -Ergonomics +Ergonomics Irrelevant. -Compatibility +Compatibility The change is backwards compatible if done in two steps: modify the sender to always send one transaction per notification, then, after a while, modify the receiver to enforce the new format. -Prior Art and References +Prior Art and References Irrelevant. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material None. This is a simple isolated change. (source) Table of Contents @@ -5209,20 +9385,20 @@ This is equivalent to forcing the Vec<Transaction> to always AuthorsPierre Krieger -Summary +Summary This RFC proposes to make the mechanism of RFC #8 more generic by introducing the concept of "capabilities". Implementations can implement certain "capabilities", such as serving old block headers or being a parachain bootnode. The discovery mechanism of RFC #8 is extended to be able to discover nodes of specific capabilities. -Motivation +Motivation The Polkadot peer-to-peer network is made of nodes. Not all these nodes are equal. Some nodes store only the headers of recent blocks, some nodes store all the block headers and bodies since the genesis, some nodes store the storage of all blocks since the genesis, and so on. It is currently not possible to know ahead of time (without connecting to it and asking) which nodes have which data available, and it is not easily possible to build a list of nodes that have a specific piece of data available. If you want to download for example the header of block 500, you have to connect to a randomly-chosen node, ask it for block 500, and if it says that it doesn't have the block, disconnect and try another randomly-chosen node. In certain situations such as downloading the storage of old blocks, nodes that have the information are relatively rare, and finding through trial and error a node that has the data can take a long time. This RFC attempts to solve this problem by giving the possibility to build a list of nodes that are capable of serving specific data. -Stakeholders +Stakeholders Low-level client developers. People interested in accessing the archive of the chain. -Explanation +Explanation Reading RFC #8 first might help with comprehension, as this RFC is very similar. Please keep in mind while reading that everything below applies for both relay chains and parachains, except mentioned otherwise. Capabilities @@ -5258,30 +9434,30 @@ If blocks pruning is enabled and the chain is a relay chain, then Substrate unfo Implementations that have the head of the chain provider capability do not register themselves as providers, but instead are the nodes that participate in the main DHT. In other words, they are the nodes that serve requests of the /<genesis_hash>/kad protocol. Any implementation that isn't a head of the chain provider (read: light clients) must not participate in the main DHT. This is already presently the case. Implementations must not participate in the main DHT if they don't fulfill the capability yet. For example, a node that is still in the process of warp syncing must not participate in the main DHT. However, assuming that warp syncing doesn't last more than a few seconds, it is acceptable to ignore this requirement in order to avoid complicating implementations too much. -Drawbacks +Drawbacks None that I can see. -Testing, Security, and Privacy +Testing, Security, and Privacy The content of this section is basically the same as the one in RFC 8. This mechanism doesn't add or remove any security by itself, as it relies on existing mechanisms. Due to the way Kademlia works, it would become the responsibility of the 20 Polkadot nodes whose sha256(peer_id) is closest to the key (described in the explanations section) to store the list of nodes that have specific capabilities. Furthermore, when a large number of providers are registered, only the providers closest to the key are kept, up to a certain implementation-defined limit. For this reason, an attacker can abuse this mechanism by randomly generating libp2p PeerIds until they find the 20 entries closest to the key representing the target capability. They are then in control of the list of nodes with that capability. While doing this can in no way be actually harmful, it could lead to eclipse attacks. Because the key changes periodically and isn't predictable, and assuming that the Polkadot DHT is sufficiently large, it is not realistic for an attack like this to be maintained in the long term. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance The DHT mechanism generally has a low overhead, especially given that publishing providers is done only every 24 hours. Doing a Kademlia iterative query then sending a provider record shouldn't take more than around 50 kiB in total of bandwidth for the parachain bootnode. Assuming 1000 nodes with a specific capability, the 20 Polkadot full nodes corresponding to that capability will each receive a sudden spike of a few megabytes of networking traffic when the key rotates. Again, this is relatively negligible. If this becomes a problem, one can add a random delay before a node registers itself to be the provider of the key corresponding to BabeApi_next_epoch. Maybe the biggest uncertainty is the traffic that the 20 Polkadot full nodes will receive from light clients that desire knowing the nodes with a capability. If this every becomes a problem, this value of 20 is an arbitrary constant that can be increased for more redundancy. -Ergonomics +Ergonomics Irrelevant. -Compatibility +Compatibility Irrelevant. -Prior Art and References +Prior Art and References Unknown. -Unresolved Questions +Unresolved Questions While it fundamentally doesn't change much to this RFC, using BabeApi_currentEpoch and BabeApi_nextEpoch might be inappropriate. I'm not familiar enough with good practices within the runtime to have an opinion here. Should it be an entirely new pallet? -Future Directions and Related Material +Future Directions and Related Material This RFC would make it possible to reliably discover archive nodes, which would make it possible to reliably send archive node requests, something that isn't currently possible. This could solve the problem of finding archive RPC node providers by migrating archive-related request to using the native peer-to-peer protocol rather than JSON-RPC. If we ever decide to break backwards compatibility, we could divide the "history" and "archive" capabilities in two, between nodes capable of serving older blocks and nodes capable of serving newer blocks. We could even add to the peer-to-peer network nodes that are only capable of serving older blocks (by reading from a database) but do not participate in the head of the chain, and that just exist for historical purposes. @@ -5330,12 +9506,12 @@ We could even add to the peer-to-peer network nodes that are only capable of ser AuthorsZondax AG, Parity Technologies -Summary +Summary To interact with chains in the Polkadot ecosystem it is required to know how transactions are encoded and how to read state. For doing this, Polkadot-SDK, the framework used by most of the chains in the Polkadot ecosystem, exposes metadata about the runtime to the outside. UIs, wallets, and others can use this metadata to interact with these chains. This makes the metadata a crucial piece of the transaction encoding as users are relying on the interacting software to encode the transactions in the correct format. It gets even more important when the user signs the transaction in an offline wallet, as the device by its nature cannot get access to the metadata without relying on the online wallet to provide it. This makes it so that the offline wallet needs to trust an online party, deeming the security assumptions of the offline devices, mute. This RFC proposes a way for offline wallets to leverage metadata, within the constraints of these. The design idea is that the metadata is chunked and these chunks are put into a merkle tree. The root hash of this merkle tree represents the metadata. The offline wallets can use the root hash to decode transactions by getting proofs for the individual chunks of the metadata. This root hash is also included in the signed data of the transaction (but not sent as part of the transaction). The runtime is then including its known metadata root hash when verifying the transaction. If the metadata root hash known by the runtime differs from the one that the offline wallet used, it very likely means that the online wallet provided some fake data and the verification of the transaction fails. Users depend on offline wallets to correctly display decoded transactions before signing. With merkleized metadata, they can be assured of the transaction's legitimacy, as incorrect transactions will be rejected by the runtime. -Motivation +Motivation Polkadot's innovative design (both relay chain and parachains) present the ability to developers to upgrade their network as frequently as they need. These systems manage to have integrations working after the upgrades with the help of FRAME Metadata. This Metadata, which is in the order of half a MiB for most Polkadot-SDK chains, completely describes chain interfaces and properties. Securing this metadata is key for users to be able to interact with the Polkadot-SDK chain in the expected way. On the other hand, offline wallets provide a secure way for Blockchain users to hold their own keys (some do a better job than others). These devices seldomly get upgraded, usually account for one particular network and hold very small internal memories. Currently in the Polkadot ecosystem there is no secure way of having these offline devices know the latest Metadata of the Polkadot-SDK chain they are interacting with. This results in a plethora of similar yet slightly different offline wallets for all different Polkadot-SDK chains, as well as the impediment of keeping these regularly updated, thus not fully leveraging Polkadot-SDK’s unique forkless upgrade feature. The two main reasons why this is not possible today are: @@ -5344,7 +9520,7 @@ We could even add to the peer-to-peer network nodes that are only capable of ser Metadata is not authenticated. Even if there was enough space on offline devices to hold the metadata, the user would be trusting the entity providing this metadata to the hardware wallet. In the Polkadot ecosystem, this is how currently Polkadot Vault works. This RFC proposes a solution to make FRAME Metadata compatible with offline signers in a secure way. As it leverages FRAME Metadata, it does not only ensure that offline devices can always keep up to date with every FRAME based chain, but also that every offline wallet will be compatible with all FRAME based chains, avoiding the need of per-chain implementations. -Requirements +Requirements Metadata's integrity MUST be preserved. If any compromise were to happen, extrinsics sent with compromised metadata SHOULD fail. Metadata information that could be used in signable extrinsic decoding MAY be included in digest, yet its inclusion MUST be indicated in signed extensions. @@ -5362,14 +9538,14 @@ We could even add to the peer-to-peer network nodes that are only capable of ser Chunks handling mechanism SHOULD support chunks being sent in any order without memory utilization overhead; Unused enum variants MUST be stripped (this has great impact on transmitted metadata size; examples: era enum, enum with all calls for call batching). -Stakeholders +Stakeholders Runtime implementors UI/wallet implementors Offline wallet implementors The idea for this RFC was brought up by runtime implementors and was extensively discussed with offline wallet implementors. It was designed in such a way that it can work easily with the existing offline wallet solutions in the Polkadot ecosystem. -Explanation +Explanation The FRAME metadata provides a wide range of information about a FRAME based runtime. It contains information about the pallets, the calls per pallet, the storage entries per pallet, runtime APIs, and type information about most of the types that are used in the runtime. For decoding extrinsics on an offline wallet, what is mainly required is type information. Most of the other information in the FRAME metadata is actually not required for decoding extrinsics and thus it can be removed. Therefore, the following is a proposal on a custom representation of the metadata and how this custom metadata is chunked, ensuring that only the needed chunks required for decoding a particular extrinsic are sent to the offline wallet. The necessary information to transform the FRAME metadata type information into the type information presented in this RFC will be provided. However, not every single detail on how to convert from FRAME metadata into the RFC type information is described. First, the MetadataDigest is introduced. After that, ExtrinsicMetadata is covered and finally the actual format of the type information. Then pruning of unrelated type information is covered and how to generate the TypeRefs. In the latest step, merkle tree calculation is explained. Metadata digest @@ -5640,23 +9816,23 @@ nodes: [[[2, 3], [4, 5]], [0, 1]] Included in the extrinsic is u8, the "mode". The mode is either 0 which means to not include the metadata hash in the signed data or the mode is 1 to include the metadata hash in V1. Included in the signed data is an Option<[u8; 32]>. Depending on the mode the value is either None or Some(metadata_hash). -Drawbacks +Drawbacks The chunking may not be the optimal case for every kind of offline wallet. -Testing, Security, and Privacy +Testing, Security, and Privacy All implementations are required to strictly follow the RFC to generate the metadata hash. This includes which hash function to use and how to construct the metadata types tree. So, all implementations are following the same security criteria. As the chains will calculate the metadata hash at compile time, the build process needs to be trusted. However, this is already a solved problem in the Polkadot ecosystem by using reproducible builds. So, anyone can rebuild a chain runtime to ensure that a proposal is actually containing the changes as advertised. Implementations can also be tested easily against each other by taking some metadata and ensuring that they all come to the same metadata hash. Privacy of users should also not be impacted. This assumes that wallets will generate the metadata hash locally and don't leak any information to third party services about which chunks a user will send to their offline wallet. Besides that, there is no leak of private information as getting the raw metadata from the chain is an operation that is done by almost everyone. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance There should be no measurable impact on performance to Polkadot or any other chain using this feature. The metadata root hash is calculated at compile time and at runtime it is optionally used when checking the signature of a transaction. This means that at runtime no performance heavy operations are done. -Ergonomics & Compatibility +Ergonomics & Compatibility The proposal alters the way a transaction is built, signed, and verified. So, this imposes some required changes to any kind of developer who wants to construct transactions for Polkadot or any chain using this feature. As the developer can pass 0 for disabling the verification of the metadata root hash, it can be easily ignored. -Prior Art and References +Prior Art and References RFC 46 produced by the Alzymologist team is a previous work reference that goes in this direction as well. On other ecosystems, there are other solutions to the problem of trusted signing. Cosmos for example has a standardized way of transforming a transaction into some textual representation and this textual representation is included in the signed data. Basically achieving the same as what the RFC proposes, but it requires that for every transaction applied in a block, every node in the network always has to generate this textual representation to ensure the transaction signature is valid. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material Does it work with all kind of offline wallets? Generic types currently appear multiple times in the metadata with each instantiation. It could be may be useful to have generic type only once in the metadata and declare the generic parameters at their instantiation. @@ -5694,20 +9870,20 @@ nodes: [[[2, 3], [4, 5]], [0, 1]] AuthorsGeorge Pisaltu -Summary +Summary This RFC proposes a change to the extrinsic format to incorporate a new transaction type, the "general" transaction. -Motivation +Motivation "General" transactions, a new type of transaction that this RFC aims to support, are transactions which obey the runtime's extensions and have according extension data yet do not have hard-coded signatures. They are first described in Extrinsic Horizon and supported in 3685. They enable users to authorize origins in new, more flexible ways (e.g. ZK proofs, mutations over pre-authenticated origins). As of now, all transactions are limited to the account signing model for origin authorization and any additional origin changes happen in extrinsic logic, which cannot leverage the validation process of extensions. An example of a use case for such an extension would be sponsoring the transaction fee for some other user. A new extension would be put in place to verify that a part of the initial payload was signed by the author under who the extrinsic should run and change the origin, but the payment for the whole transaction should be handled under a sponsor's account. A POC for this can be found in 3712. The new "general" transaction type would coexist with both current transaction types for a while and, therefore, the current number of supported transaction types, capped at 2, is insufficient. A new extrinsic type must be introduced alongside the current signed and unsigned types. Currently, an encoded extrinsic's first byte indicate the type of extrinsic using the most significant bit - 0 for unsigned, 1 for signed - and the 7 following bits indicate the extrinsic format version, which has been equal to 4 for a long time. By taking one bit from the extrinsic format version encoding, we can support 2 additional extrinsic types while also having a minimal impact on our capability to extend and change the extrinsic format in the future. -Stakeholders +Stakeholders Runtime users Runtime devs Wallet devs -Explanation +Explanation An extrinsic is currently encoded as one byte to identify the extrinsic type and version. This RFC aims to change the interpretation of this byte regarding the reserved bits for the extrinsic type and version. In the following explanation, bits represented using T make up the extrinsic type and bits represented using V make up the extrinsic version. Currently, the bit allocation within the leading encoded byte is 0bTVVV_VVVV. In practice in the Polkadot ecosystem, the leading byte would be 0bT000_0100 as the version has been equal to 4 for a long time. This RFC proposes for the bit allocation to change to 0bTTVV_VVVV. As a result, the extrinsic format version will be bumped to 5 and the extrinsic type bit representation would change as follows: @@ -5718,23 +9894,23 @@ nodes: [[[2, 3], [4, 5]], [0, 1]] 11reserved -Drawbacks +Drawbacks This change would reduce the maximum possible transaction version from the current 127 to 63. In order to bypass the new, lower limit, the extrinsic format would have to change again. -Testing, Security, and Privacy +Testing, Security, and Privacy There is no impact on testing, security or privacy. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility This change would allow Polkadot to support new types of transactions, with the specific "general" transaction type in mind at the time of writing this proposal. -Performance +Performance There is no performance impact. -Ergonomics +Ergonomics The impact to developers and end-users is minimal as it would just be a bitmask update on their part for parsing the extrinsic type along with the version. -Compatibility +Compatibility This change breaks backwards compatiblity because any transaction that is neither signed nor unsigned, but a new transaction type, would be interpreted as having a future extrinsic format version. -Prior Art and References +Prior Art and References The original design was originally proposed in the TransactionExtension PR, which is also the motivation behind this effort. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material Following this change, the "general" transaction type will be introduced as part of the Extrinsic Horizon effort, which will shape future work. (source) Table of Contents @@ -5767,16 +9943,16 @@ nodes: [[[2, 3], [4, 5]], [0, 1]] AuthorsAlex Gheorghe (alexggh) -Summary +Summary Extend the DHT authority discovery records with a signed creation time, so that nodes can determine which record is newer and always decide to prefer the newer records to the old ones. -Motivation +Motivation Currently, we use the Kademlia DHT for storing records regarding the p2p address of an authority discovery key, the problem is that if the nodes decide to change its PeerId/Network key it will publish a new record, however because of the distributed and replicated nature of the DHT there is no way to tell which record is newer so both old PeerId and the new PeerId will live in the network until the old one expires(36h), that creates all sort of problem and leads to the node changing its address not being properly connected for up to 36h. After this RFC, nodes are extended to decide to keep the new record and propagate the new record to nodes that have the old record stored, so in the end all the nodes will converge faster to the new record(in the order of minutes, not 36h) Implementation of the rfc: https://github.com/paritytech/polkadot-sdk/pull/3786. Current issue without this enhacement: https://github.com/paritytech/polkadot-sdk/issues/3673 -Stakeholders +Stakeholders Polkadot node developers. -Explanation +Explanation This RFC heavily relies on the functionalities of the Kademlia DHT already in use by Polkadot. You can find a link to the specification here. In a nutshell, on a specific node the current authority-discovery protocol publishes Kademila DHT records at startup and periodically. The records contain the full address of the node for each authorithy key it owns. The node tries also to find the full address of all authorities in the network by querying the DHT and picking up the first record it finds for each of the authority id it found on chain. @@ -5809,24 +9985,24 @@ You can find a link to the specification Drawbacks +Drawbacks In theory the new protocol creates a bit more traffic on the DHT network, because it waits for DHT records to be received from more than one node, while in the current implementation we just take the first record that we receive and cancel all in-flight requests to other peers. However, because the redundancy factor will be relatively small and this operation happens rarerly, every 10min, this cost is negligible. -Testing, Security, and Privacy +Testing, Security, and Privacy This RFC's implementation https://github.com/paritytech/polkadot-sdk/pull/3786 had been tested on various local test networks and versi. With regard to security the creation time is wrapped inside SignedAuthorityRecord wo it will be signed with the authority id key, so there is no way for other malicious nodes to manipulate this field without the received node observing. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility Irrelevant. -Performance +Performance Irrelevant. -Ergonomics +Ergonomics Irrelevant. -Compatibility +Compatibility The changes are backwards compatible with the existing protocol, so nodes with both the old protocol and newer protocol can exist in the network, this is achieved by the fact that we use protobuf for serializing and deserializing the records, so new fields will be ignore when deserializing with the older protocol and vice-versa when deserializing an old record with the new protocol the new field will be None and the new code accepts this record as being valid. -Prior Art and References +Prior Art and References The enhancements have been inspired by the algorithm specified in here -Unresolved Questions +Unresolved Questions N/A -Future Directions and Related Material +Future Directions and Related Material N/A (source) Table of Contents @@ -5872,23 +10048,23 @@ in order to speed up the time until all nodes have the newest record, nodes can AuthorsJonas Gehrlein & Alistair Stewart -Summary +Summary This RFC proposes a flexible unbonding mechanism for tokens that are locked from staking on the Relay Chain (DOT/KSM), aiming to enhance user convenience without compromising system security. Locking tokens for staking ensures that Polkadot is able to slash tokens backing misbehaving validators. With changing the locking period, we still need to make sure that Polkadot can slash enough tokens to deter misbehaviour. This means that not all tokens can be unbonded immediately, however we can still allow some tokens to be unbonded quickly. The new mechanism leads to a signficantly reduced unbonding time on average, by queuing up new unbonding requests and scaling their unbonding duration relative to the size of the queue. New requests are executed with a minimum of 2 days, when the queue is comparatively empty, to the conventional 28 days, if the sum of requests (in terms of stake) exceed some threshold. In scenarios between these two bounds, the unbonding duration scales proportionately. The new mechanism will never be worse than the current fixed 28 days. In this document we also present an empirical analysis by retrospectively fitting the proposed mechanism to the historic unbonding timeline and show that the average unbonding duration would drastically reduce, while still being sensitive to large unbonding events. Additionally, we discuss implications for UI, UX, and conviction voting. Note: Our proposition solely focuses on the locks imposed from staking. Other locks, such as governance, remain unchanged. Also, this mechanism should not be confused with the already existing feature of FastUnstake, which lets users unstake tokens immediately that have not received rewards for 28 days or longer. As an initial step to gauge its effectiveness and stability, it is recommended to implement and test this model on Kusama before considering its integration into Polkadot, with appropriate adjustments to the parameters. In the following, however, we limit our discussion to Polkadot. -Motivation +Motivation Polkadot has one of the longest unbonding periods among all Proof-of-Stake protocols, because security is the most important goal. Staking on Polkadot is still attractive compared to other protocols because of its above-average staking APY. However the long unbonding period harms usability and deters potential participants that want to contribute to the security of the network. The current length of the unbonding period imposes significant costs for any entity that even wants to perform basic tasks such as a reorganization / consolidation of their stashes, or updating their private key infrastructure. It also limits participation of users that have a large preference for liquidity. The combination of long unbonding periods and high returns has lead to the proliferation of liquid staking, where parachains or centralised exchanges offer users their staked tokens before the 28 days unbonding period is over either in original DOT/KSM form or derivative tokens. Liquid staking is harmless if few tokens are involved but it could result in many validators being selected by a few entities if a large fraction of DOTs were involved. This may lead to centralization (see here for more discussion on threats of liquid staking) and an opportunity for attacks. The new mechanism greatly increases the competitiveness of Polkadot, while maintaining sufficient security. -Stakeholders +Stakeholders Every DOT/KSM token holder -Explanation +Explanation Before diving into the details of how to implement the unbonding queue, we give readers context about why Polkadot has a 28-day unbonding period in the first place. The reason for it is to prevent long-range attacks (LRA) that becomes theoretically possible if more than 1/3 of validators collude. In essence, a LRA describes the inability of users, who disconnect from the consensus at time t0 and reconnects later, to realize that validators which were legitimate at a certain time, say t0 but dropped out in the meantime, are not to be trusted anymore. That means, for example, a user syncing the state could be fooled by trusting validators that fell outside the active set of validators after t0, and are building a competitive and malicious chain (fork). LRAs of longer than 28 days are mitigated by the use of trusted checkpoints, which are assumed to be no more than 28 days old. A new node that syncs Polkadot will start at the checkpoint and look for proofs of finality of later blocks, signed by 2/3 of the validators. In an LRA fork, some of the validator sets may be different but only if 2/3 of some validator set in the last 28 days signed something incorrect. If we detect an LRA of no more than 28 days with the current unbonding period, then we should be able to detect misbehaviour from over 1/3 of validators whose nominators are still bonded. The stake backing these validators is considerable fraction of the total stake (empirically it is 0.287 or so). If we allowed more than this stake to unbond, without checking who it was backing, then the LRA attack might be free of cost for an attacker. The proposed mechansim allows up to half this stake to unbond within 28 days. This halves the amount of tokens that can be slashed, but this is still very high in absolute terms. For example, at the time of writing (19.06.2024) this would translate to around 120 millions DOTs. @@ -5946,23 +10122,23 @@ The analysis can be reproduced or changed to other parameters using Potential Extension In addition to a simple queue, we could add a market component that lets users always unbond from staking at the minimum possible waiting time)(== LOWER_BOUND, e.g., 2 days), by paying a variable fee. To achieve this, it is reasonable to split the total unbonding capacity into two chunks, with the first capacity for the simple queue and the remaining capacity for the fee-based unbonding. By doing so, we allow users to choose whether they want the quickest unbond and paying a dynamic fee or join the simple queue. Setting a capacity restriction for both queues enables us to guarantee a predictable unbonding time in the simple queue, while allowing users with the respective willingness to pay to get out even earlier. The fees are dynamically adjusted and are proportional to the unbonding stake (and thereby expressed in a percentage of the requested unbonding stake). In contrast to a unified queue, this prevents the issue that users paying a fee jump in front of other users not paying a fee, pushing their unbonding time back (which would be bad for UX). The revenue generated could be burned. This extension and further specifications are left out of this RFC, because it adds further complexity and the empirical analysis above suggests that average unbonding times will already be close the LOWER_BOUND, making a more complex design unnecessary. We advise to first implement the discussed mechanism and assess after some experience whether an extension is desirable. -Drawbacks +Drawbacks Lower security for LRAs: Without a doubt, the theoretical security against LRAs decreases. But, as we argue, the attack is still costly enough to deter attacks and the attack is sufficiently theoretical. Here, the benefits outweigh the costs. Griefing attacks: A large holder could pretend to unbond a large amount of their tokens to prevent other users to exit the network earlier. This would, however be costly due to the fact that the holder loses out on staking rewards. The larger the impact on the queue, the higher the costs. In any case it must be noted that the UPPER_BOUND is still 28 days, which means that nominators are never left with a longer unbonding period than currently. There is not enough gain for the attacker to endure this cost. Challenge for Custodians and Liquid Staking Providers: Changing the unbonding time, especially making it flexible, requires entities that offer staking derivatives to rethink and rework their products. -Testing, Security, and Privacy +Testing, Security, and Privacy NA -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility NA -Performance +Performance The authors cannot see any potential impact on performance. -Ergonomics +Ergonomics The authors cannot see any potential impact on ergonomics for developers. We discussed potential impact on UX/UI for users above. -Compatibility +Compatibility The authors cannot see any potential impact on compatibility. This should be assessed by the technical fellows. -Prior Art and References +Prior Art and References Ethereum proposed a similar solution Alistair did some initial write-up @@ -5999,20 +10175,20 @@ The analysis can be reproduced or changed to other parameters using Summary +Summary This RFC proposes a change to the extrinsic format to include a transaction extension version. -Motivation +Motivation The extrinsic format supports to be extended with transaction extensions. These transaction extensions are runtime specific and can be different per chain. Each transaction extension can add data to the extrinsic itself or extend the signed payload. This means that adding a transaction extension is breaking the chain specific extrinsic format. A recent example was the introduction of the CheckMetadatHash to Polkadot and all its system chains. As the extension was adding one byte to the extrinsic, it broke a lot of tooling. By introducing an extra version for the transaction extensions it will be possible to introduce changes to these transaction extensions while still being backwards compatible. Based on the version of the transaction extensions, each chain runtime could decode the extrinsic correctly and also create the correct signed payload. -Stakeholders +Stakeholders Runtime users Runtime devs Wallet devs -Explanation +Explanation RFC84 introduced the extrinsic format 5. The idea is to piggyback onto this change of the extrinsic format to add the extra version for the transaction extensions. If required, this could also come as extrinsic format 6, but 5 is not yet deployed anywhere. The extrinsic format supports the following types of transactions: @@ -6028,25 +10204,25 @@ as extrinsic format 6, but 5 is not yet deployed anywh The Version being a SCALE encoded u8 representing the version of the transaction extensions. In the chain runtime the version can be used to determine which set of transaction extensions should be used to decode and to validate the transaction. -Drawbacks +Drawbacks This adds one byte more to each signed transaction. -Testing, Security, and Privacy +Testing, Security, and Privacy There is no impact on testing, security or privacy. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility This will ensure that changes to the transactions extensions can be done in a backwards compatible way. -Performance +Performance There is no performance impact. -Ergonomics +Ergonomics Runtime developers need to take care of the versioning and ensure to bump as required, so that there are no compatibility breaking changes without a bump of the version. It will also add a little bit more code in the runtime to decode these old versions, but this should be neglectable. -Compatibility +Compatibility When introduced together with extrinsic format version 5 from RFC84, it can be implemented in a backwards compatible way. So, transactions can still be send using the old extrinsic format and decoded by the runtime. -Prior Art and References +Prior Art and References None. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material None. (source) Table of Contents @@ -6083,14 +10259,14 @@ old extrinsic format and decoded by the runtime. AuthorsAdrian Catangiu -Summary +Summary This RFC proposes a new instruction that provides a way to initiate on remote chains, asset transfers which transfer multiple types (teleports, local-reserve, destination-reserve) of assets, using XCM alone. The currently existing instructions are too opinionated and force each XCM asset transfer to a single transfer type (teleport, local-reserve, destination-reserve). This results in inability to combine different types of transfers in single transfer which results in overall poor UX when trying to move assets across chains. -Motivation +Motivation XCM is the de-facto cross-chain messaging protocol within the Polkadot ecosystem, and cross-chain assets transfers is one of its main use-cases. Unfortunately, in its current spec, it does not support initiating on a remote chain, one or more transfers that combine assets with different transfer types. @@ -6112,14 +10288,14 @@ For example, allows single XCM program execution to transfer multiple assets fro Kusama Asset Hub, over the bridge through Polkadot Asset Hub with final destination ParaP on Polkadot. With current XCM, we are limited to doing multiple independent transfers for each individual hop in order to move both "interesting" assets, but also "supporting" assets (used to pay fees). -Stakeholders +Stakeholders Runtime users Runtime devs Wallet devs dApps devs -Explanation +Explanation A new instruction InitiateAssetsTransfer is introduced that initiates an assets transfer from the chain it is executed on, to another chain. The executed transfer is point-to-point (chain-to-chain) with all of the transfer properties specified in the instruction parameters. The instruction also @@ -6307,9 +10483,9 @@ by executing a single XCM message, even though we'll be mixing multiple ).unwrap(); }) } -Drawbacks +Drawbacks No drawbacks identified. -Testing, Security, and Privacy +Testing, Security, and Privacy There should be no security risks related to the new instruction from the XCVM perspective. It follows the same pattern as with single-type asset transfers, only now it allows combining multiple types at once. Improves security by enabling @@ -6318,16 +10494,16 @@ which minimizes the potential free/unpaid work that a receiving chain has to do. required execution fee payment, part of the instruction logic through the remote_fees: Option<AssetTransferFilter> parameter, which will make sure the remote XCM starts with a single-asset-holding-loading-instruction, immediately followed by a BuyExecution using said asset. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility This brings no impact to the rest of the XCM spec. It is a new, independent instruction, no changes to existing instructions. Enhances the exposed functionality of Polkadot. Will allow multi-chain transfers that are currently forced to happen in multiple programs per asset per "hop", to be possible in a single XCM program. -Performance +Performance No performance changes/implications. -Ergonomics +Ergonomics The proposal enhances developers' and users' cross-chain asset transfer capabilities. This enhancement is optimized for XCM programs transferring multiple assets, needing to run their logic across multiple chains. -Compatibility +Compatibility Does this proposal break compatibility with existing interfaces, older versions of implementations? Summarize necessary migrations or upgrade strategies, if any. This enhancement is compatible with all existing XCM programs and versions. @@ -6336,11 +10512,11 @@ success. A program where the new instruction is used to initiate multiple types of asset transfers, cannot be downgraded to older XCM versions, because there is no equivalent capability there. Such conversion attempts will explicitly fail. -Prior Art and References +Prior Art and References None. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material None. (source) Table of Contents @@ -6373,10 +10549,10 @@ Such conversion attempts will explicitly fail. AuthorsAdrian Catangiu -Summary +Summary The Transact XCM instruction currently forces the user to set a specific maximum weight allowed to the inner call and then also pay for that much weight regardless of how much the call actually needs in practice. This RFC proposes improving the usability of Transact by removing that parameter and instead get and charge the actual weight of the inner call from its dispatch info on the remote chain. -Motivation +Motivation The UX of using Transact is poor because of having to guess/estimate the require_weight_at_most weight used by the inner call on the target. We've seen multiple Transact on-chain failures caused by guessing wrong values for this require_weight_at_most even though the rest of the XCM program would have worked. In practice, this parameter only adds UX overhead with no real practical value. Use cases fall in one of two categories: @@ -6389,40 +10565,40 @@ weight limit parameter. We've had multiple OpenGov root/whitelisted_caller proposals initiated by core-devs completely or partially fail because of incorrect configuration of require_weight_at_most parameter. This is a strong indication that the instruction is hard to use. -Stakeholders +Stakeholders
#![allow(unused)] fn main() { @@ -4921,31 +9097,31 @@ actual exported function signature looks like: already gets the proof passed as Vec<u8>. This proof needs to be decoded to the actual Proof type as explained above. The proof and the SCALE encoded account_id of the sender are used to verify the ownership of the SessionKeys. -Drawbacks +Drawbacks Validator operators need to pass the their account id when rotating their session keys in a node. This will require updating some high level docs and making users familiar with the slightly changed ergonomics. -Testing, Security, and Privacy +Testing, Security, and Privacy Testing of the new changes only requires passing an appropriate owner for the current testing context. The changes to the proof generation and verification got audited to ensure they are correct. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance The session key generation is an offchain process and thus, doesn't influence the performance of the chain. Verifying the proof is done on chain as part of the transaction logic for setting the session keys. The verification of the proof is a signature verification number of individual session keys times. As setting the session keys is happening quite rarely, it should not influence the overall system performance. -Ergonomics +Ergonomics The interfaces have been optimized to make it as easy as possible to generate the ownership proof. -Compatibility +Compatibility Introduces a new version of the SessionKeys runtime api. Thus, nodes should be updated before a runtime is enacted that contains these changes otherwise they will fail to generate session keys. The RPC that exists around this runtime api needs to be updated to support passing the account id and for returning the ownership proof alongside the public session keys. UIs would need to be updated to support the new RPC and the changed on chain logic. -Prior Art and References +Prior Art and References None. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material Substrate implementation of the RFC. (source) Table of Contents @@ -4983,10 +9159,10 @@ and for returning the ownership proof alongside the public session keys. AuthorsJoe Petrowski, Gavin Wood -Summary +Summary The Fellowship Manifesto states that members should receive a monthly allowance on par with gross income in OECD countries. This RFC proposes concrete amounts. -Motivation +Motivation One motivation for the Technical Fellowship is to provide an incentive mechanism that can induct and retain technical talent for the continued progress of the network. In order for members to uphold their commitment to the network, they should receive support to @@ -4996,12 +9172,12 @@ on par with a full-time job. Providing a livable wage to those making such contr pragmatic to work full-time on Polkadot. Note: Goals of the Fellowship, expectations for each Dan, and conditions for promotion and demotion are all explained in the Manifesto. This RFC is only to propose concrete values for allowances. -Stakeholders +Stakeholders Fellowship members Polkadot Treasury -Explanation +Explanation This RFC proposes agreeing on salaries relative to a single level, the III Dan. As such, changes to the amount or asset used would only be on a single value, and all others would adjust relatively. A III Dan is someone whose contributions match the expectations of a full-time individual contributor. @@ -5061,19 +9237,19 @@ other hand, more people will likely join the Fellowship in the coming years. Updates Updates to these levels, whether relative ratios, the asset used, or the amount, shall be done via RFC. -Drawbacks +Drawbacks By not using DOT for payment, the protocol relies on the stability of other assets and the ability to acquire them. However, the asset of choice can be changed in the future. -Testing, Security, and Privacy +Testing, Security, and Privacy N/A. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance N/A -Ergonomics +Ergonomics N/A -Compatibility +Compatibility N/A -Prior Art and References +Prior Art and References The Polkadot Fellowship Manifesto @@ -5081,7 +9257,7 @@ Manifesto Indeed: Average Salary for Engineers, United States -Unresolved Questions +Unresolved Questions None at present. (source) Table of Contents @@ -5114,11 +9290,11 @@ States AuthorsPierre Krieger -Summary +Summary When two peers connect to each other, they open (amongst other things) a so-called "notifications protocol" substream dedicated to gossiping transactions to each other. Each notification on this substream currently consists in a SCALE-encoded Vec<Transaction> where Transaction is defined in the runtime. This RFC proposes to modify the format of the notification to become (Compact(1), Transaction). This maintains backwards compatibility, as this new format decodes as a Vec of length equal to 1. -Motivation +Motivation There exists three motivations behind this change: @@ -5131,9 +9307,9 @@ States It makes the implementation way more straight-forward by not having to repeat code related to back-pressure. See explanations below. -Stakeholders +Stakeholders Low-level developers. -Explanation +Explanation To give an example, if you send one notification with three transactions, the bytes that are sent on the wire are: concat( leb128(total-size-in-bytes-of-the-rest), @@ -5153,23 +9329,23 @@ A SCALE-compact encoded 1 is one byte of value 4. In o This is equivalent to forcing the Vec<Transaction> to always have a length of 1, and I expect the Substrate implementation to simply modify the sending side to add a for loop that sends one notification per item in the Vec. As explained in the motivation section, this allows extracting scale(transaction) items without having to know how to decode them. By "flattening" the two-steps hierarchy, an implementation only needs to back-pressure individual notifications rather than back-pressure notifications and transactions within notifications. -Drawbacks +Drawbacks This RFC chooses to maintain backwards compatibility at the cost of introducing a very small wart (the Compact(1)). An alternative could be to introduce a new version of the transactions notifications protocol that sends one Transaction per notification, but this is significantly more complicated to implement and can always be done later in case the Compact(1) is bothersome. -Testing, Security, and Privacy +Testing, Security, and Privacy Irrelevant. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance Irrelevant. -Ergonomics +Ergonomics Irrelevant. -Compatibility +Compatibility The change is backwards compatible if done in two steps: modify the sender to always send one transaction per notification, then, after a while, modify the receiver to enforce the new format. -Prior Art and References +Prior Art and References Irrelevant. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material None. This is a simple isolated change. (source) Table of Contents @@ -5209,20 +9385,20 @@ This is equivalent to forcing the Vec<Transaction> to always AuthorsPierre Krieger -Summary +Summary This RFC proposes to make the mechanism of RFC #8 more generic by introducing the concept of "capabilities". Implementations can implement certain "capabilities", such as serving old block headers or being a parachain bootnode. The discovery mechanism of RFC #8 is extended to be able to discover nodes of specific capabilities. -Motivation +Motivation The Polkadot peer-to-peer network is made of nodes. Not all these nodes are equal. Some nodes store only the headers of recent blocks, some nodes store all the block headers and bodies since the genesis, some nodes store the storage of all blocks since the genesis, and so on. It is currently not possible to know ahead of time (without connecting to it and asking) which nodes have which data available, and it is not easily possible to build a list of nodes that have a specific piece of data available. If you want to download for example the header of block 500, you have to connect to a randomly-chosen node, ask it for block 500, and if it says that it doesn't have the block, disconnect and try another randomly-chosen node. In certain situations such as downloading the storage of old blocks, nodes that have the information are relatively rare, and finding through trial and error a node that has the data can take a long time. This RFC attempts to solve this problem by giving the possibility to build a list of nodes that are capable of serving specific data. -Stakeholders +Stakeholders Low-level client developers. People interested in accessing the archive of the chain. -Explanation +Explanation Reading RFC #8 first might help with comprehension, as this RFC is very similar. Please keep in mind while reading that everything below applies for both relay chains and parachains, except mentioned otherwise. Capabilities @@ -5258,30 +9434,30 @@ If blocks pruning is enabled and the chain is a relay chain, then Substrate unfo Implementations that have the head of the chain provider capability do not register themselves as providers, but instead are the nodes that participate in the main DHT. In other words, they are the nodes that serve requests of the /<genesis_hash>/kad protocol. Any implementation that isn't a head of the chain provider (read: light clients) must not participate in the main DHT. This is already presently the case. Implementations must not participate in the main DHT if they don't fulfill the capability yet. For example, a node that is still in the process of warp syncing must not participate in the main DHT. However, assuming that warp syncing doesn't last more than a few seconds, it is acceptable to ignore this requirement in order to avoid complicating implementations too much. -Drawbacks +Drawbacks None that I can see. -Testing, Security, and Privacy +Testing, Security, and Privacy The content of this section is basically the same as the one in RFC 8. This mechanism doesn't add or remove any security by itself, as it relies on existing mechanisms. Due to the way Kademlia works, it would become the responsibility of the 20 Polkadot nodes whose sha256(peer_id) is closest to the key (described in the explanations section) to store the list of nodes that have specific capabilities. Furthermore, when a large number of providers are registered, only the providers closest to the key are kept, up to a certain implementation-defined limit. For this reason, an attacker can abuse this mechanism by randomly generating libp2p PeerIds until they find the 20 entries closest to the key representing the target capability. They are then in control of the list of nodes with that capability. While doing this can in no way be actually harmful, it could lead to eclipse attacks. Because the key changes periodically and isn't predictable, and assuming that the Polkadot DHT is sufficiently large, it is not realistic for an attack like this to be maintained in the long term. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance The DHT mechanism generally has a low overhead, especially given that publishing providers is done only every 24 hours. Doing a Kademlia iterative query then sending a provider record shouldn't take more than around 50 kiB in total of bandwidth for the parachain bootnode. Assuming 1000 nodes with a specific capability, the 20 Polkadot full nodes corresponding to that capability will each receive a sudden spike of a few megabytes of networking traffic when the key rotates. Again, this is relatively negligible. If this becomes a problem, one can add a random delay before a node registers itself to be the provider of the key corresponding to BabeApi_next_epoch. Maybe the biggest uncertainty is the traffic that the 20 Polkadot full nodes will receive from light clients that desire knowing the nodes with a capability. If this every becomes a problem, this value of 20 is an arbitrary constant that can be increased for more redundancy. -Ergonomics +Ergonomics Irrelevant. -Compatibility +Compatibility Irrelevant. -Prior Art and References +Prior Art and References Unknown. -Unresolved Questions +Unresolved Questions While it fundamentally doesn't change much to this RFC, using BabeApi_currentEpoch and BabeApi_nextEpoch might be inappropriate. I'm not familiar enough with good practices within the runtime to have an opinion here. Should it be an entirely new pallet? -Future Directions and Related Material +Future Directions and Related Material This RFC would make it possible to reliably discover archive nodes, which would make it possible to reliably send archive node requests, something that isn't currently possible. This could solve the problem of finding archive RPC node providers by migrating archive-related request to using the native peer-to-peer protocol rather than JSON-RPC. If we ever decide to break backwards compatibility, we could divide the "history" and "archive" capabilities in two, between nodes capable of serving older blocks and nodes capable of serving newer blocks. We could even add to the peer-to-peer network nodes that are only capable of serving older blocks (by reading from a database) but do not participate in the head of the chain, and that just exist for historical purposes. @@ -5330,12 +9506,12 @@ We could even add to the peer-to-peer network nodes that are only capable of ser AuthorsZondax AG, Parity Technologies -Summary +Summary To interact with chains in the Polkadot ecosystem it is required to know how transactions are encoded and how to read state. For doing this, Polkadot-SDK, the framework used by most of the chains in the Polkadot ecosystem, exposes metadata about the runtime to the outside. UIs, wallets, and others can use this metadata to interact with these chains. This makes the metadata a crucial piece of the transaction encoding as users are relying on the interacting software to encode the transactions in the correct format. It gets even more important when the user signs the transaction in an offline wallet, as the device by its nature cannot get access to the metadata without relying on the online wallet to provide it. This makes it so that the offline wallet needs to trust an online party, deeming the security assumptions of the offline devices, mute. This RFC proposes a way for offline wallets to leverage metadata, within the constraints of these. The design idea is that the metadata is chunked and these chunks are put into a merkle tree. The root hash of this merkle tree represents the metadata. The offline wallets can use the root hash to decode transactions by getting proofs for the individual chunks of the metadata. This root hash is also included in the signed data of the transaction (but not sent as part of the transaction). The runtime is then including its known metadata root hash when verifying the transaction. If the metadata root hash known by the runtime differs from the one that the offline wallet used, it very likely means that the online wallet provided some fake data and the verification of the transaction fails. Users depend on offline wallets to correctly display decoded transactions before signing. With merkleized metadata, they can be assured of the transaction's legitimacy, as incorrect transactions will be rejected by the runtime. -Motivation +Motivation Polkadot's innovative design (both relay chain and parachains) present the ability to developers to upgrade their network as frequently as they need. These systems manage to have integrations working after the upgrades with the help of FRAME Metadata. This Metadata, which is in the order of half a MiB for most Polkadot-SDK chains, completely describes chain interfaces and properties. Securing this metadata is key for users to be able to interact with the Polkadot-SDK chain in the expected way. On the other hand, offline wallets provide a secure way for Blockchain users to hold their own keys (some do a better job than others). These devices seldomly get upgraded, usually account for one particular network and hold very small internal memories. Currently in the Polkadot ecosystem there is no secure way of having these offline devices know the latest Metadata of the Polkadot-SDK chain they are interacting with. This results in a plethora of similar yet slightly different offline wallets for all different Polkadot-SDK chains, as well as the impediment of keeping these regularly updated, thus not fully leveraging Polkadot-SDK’s unique forkless upgrade feature. The two main reasons why this is not possible today are: @@ -5344,7 +9520,7 @@ We could even add to the peer-to-peer network nodes that are only capable of ser Metadata is not authenticated. Even if there was enough space on offline devices to hold the metadata, the user would be trusting the entity providing this metadata to the hardware wallet. In the Polkadot ecosystem, this is how currently Polkadot Vault works. This RFC proposes a solution to make FRAME Metadata compatible with offline signers in a secure way. As it leverages FRAME Metadata, it does not only ensure that offline devices can always keep up to date with every FRAME based chain, but also that every offline wallet will be compatible with all FRAME based chains, avoiding the need of per-chain implementations. -Requirements +Requirements Metadata's integrity MUST be preserved. If any compromise were to happen, extrinsics sent with compromised metadata SHOULD fail. Metadata information that could be used in signable extrinsic decoding MAY be included in digest, yet its inclusion MUST be indicated in signed extensions. @@ -5362,14 +9538,14 @@ We could even add to the peer-to-peer network nodes that are only capable of ser Chunks handling mechanism SHOULD support chunks being sent in any order without memory utilization overhead; Unused enum variants MUST be stripped (this has great impact on transmitted metadata size; examples: era enum, enum with all calls for call batching). -Stakeholders +Stakeholders Runtime implementors UI/wallet implementors Offline wallet implementors The idea for this RFC was brought up by runtime implementors and was extensively discussed with offline wallet implementors. It was designed in such a way that it can work easily with the existing offline wallet solutions in the Polkadot ecosystem. -Explanation +Explanation The FRAME metadata provides a wide range of information about a FRAME based runtime. It contains information about the pallets, the calls per pallet, the storage entries per pallet, runtime APIs, and type information about most of the types that are used in the runtime. For decoding extrinsics on an offline wallet, what is mainly required is type information. Most of the other information in the FRAME metadata is actually not required for decoding extrinsics and thus it can be removed. Therefore, the following is a proposal on a custom representation of the metadata and how this custom metadata is chunked, ensuring that only the needed chunks required for decoding a particular extrinsic are sent to the offline wallet. The necessary information to transform the FRAME metadata type information into the type information presented in this RFC will be provided. However, not every single detail on how to convert from FRAME metadata into the RFC type information is described. First, the MetadataDigest is introduced. After that, ExtrinsicMetadata is covered and finally the actual format of the type information. Then pruning of unrelated type information is covered and how to generate the TypeRefs. In the latest step, merkle tree calculation is explained. Metadata digest @@ -5640,23 +9816,23 @@ nodes: [[[2, 3], [4, 5]], [0, 1]] Included in the extrinsic is u8, the "mode". The mode is either 0 which means to not include the metadata hash in the signed data or the mode is 1 to include the metadata hash in V1. Included in the signed data is an Option<[u8; 32]>. Depending on the mode the value is either None or Some(metadata_hash). -Drawbacks +Drawbacks The chunking may not be the optimal case for every kind of offline wallet. -Testing, Security, and Privacy +Testing, Security, and Privacy All implementations are required to strictly follow the RFC to generate the metadata hash. This includes which hash function to use and how to construct the metadata types tree. So, all implementations are following the same security criteria. As the chains will calculate the metadata hash at compile time, the build process needs to be trusted. However, this is already a solved problem in the Polkadot ecosystem by using reproducible builds. So, anyone can rebuild a chain runtime to ensure that a proposal is actually containing the changes as advertised. Implementations can also be tested easily against each other by taking some metadata and ensuring that they all come to the same metadata hash. Privacy of users should also not be impacted. This assumes that wallets will generate the metadata hash locally and don't leak any information to third party services about which chunks a user will send to their offline wallet. Besides that, there is no leak of private information as getting the raw metadata from the chain is an operation that is done by almost everyone. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance There should be no measurable impact on performance to Polkadot or any other chain using this feature. The metadata root hash is calculated at compile time and at runtime it is optionally used when checking the signature of a transaction. This means that at runtime no performance heavy operations are done. -Ergonomics & Compatibility +Ergonomics & Compatibility The proposal alters the way a transaction is built, signed, and verified. So, this imposes some required changes to any kind of developer who wants to construct transactions for Polkadot or any chain using this feature. As the developer can pass 0 for disabling the verification of the metadata root hash, it can be easily ignored. -Prior Art and References +Prior Art and References RFC 46 produced by the Alzymologist team is a previous work reference that goes in this direction as well. On other ecosystems, there are other solutions to the problem of trusted signing. Cosmos for example has a standardized way of transforming a transaction into some textual representation and this textual representation is included in the signed data. Basically achieving the same as what the RFC proposes, but it requires that for every transaction applied in a block, every node in the network always has to generate this textual representation to ensure the transaction signature is valid. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material Does it work with all kind of offline wallets? Generic types currently appear multiple times in the metadata with each instantiation. It could be may be useful to have generic type only once in the metadata and declare the generic parameters at their instantiation. @@ -5694,20 +9870,20 @@ nodes: [[[2, 3], [4, 5]], [0, 1]] AuthorsGeorge Pisaltu -Summary +Summary This RFC proposes a change to the extrinsic format to incorporate a new transaction type, the "general" transaction. -Motivation +Motivation "General" transactions, a new type of transaction that this RFC aims to support, are transactions which obey the runtime's extensions and have according extension data yet do not have hard-coded signatures. They are first described in Extrinsic Horizon and supported in 3685. They enable users to authorize origins in new, more flexible ways (e.g. ZK proofs, mutations over pre-authenticated origins). As of now, all transactions are limited to the account signing model for origin authorization and any additional origin changes happen in extrinsic logic, which cannot leverage the validation process of extensions. An example of a use case for such an extension would be sponsoring the transaction fee for some other user. A new extension would be put in place to verify that a part of the initial payload was signed by the author under who the extrinsic should run and change the origin, but the payment for the whole transaction should be handled under a sponsor's account. A POC for this can be found in 3712. The new "general" transaction type would coexist with both current transaction types for a while and, therefore, the current number of supported transaction types, capped at 2, is insufficient. A new extrinsic type must be introduced alongside the current signed and unsigned types. Currently, an encoded extrinsic's first byte indicate the type of extrinsic using the most significant bit - 0 for unsigned, 1 for signed - and the 7 following bits indicate the extrinsic format version, which has been equal to 4 for a long time. By taking one bit from the extrinsic format version encoding, we can support 2 additional extrinsic types while also having a minimal impact on our capability to extend and change the extrinsic format in the future. -Stakeholders +Stakeholders Runtime users Runtime devs Wallet devs -Explanation +Explanation An extrinsic is currently encoded as one byte to identify the extrinsic type and version. This RFC aims to change the interpretation of this byte regarding the reserved bits for the extrinsic type and version. In the following explanation, bits represented using T make up the extrinsic type and bits represented using V make up the extrinsic version. Currently, the bit allocation within the leading encoded byte is 0bTVVV_VVVV. In practice in the Polkadot ecosystem, the leading byte would be 0bT000_0100 as the version has been equal to 4 for a long time. This RFC proposes for the bit allocation to change to 0bTTVV_VVVV. As a result, the extrinsic format version will be bumped to 5 and the extrinsic type bit representation would change as follows: @@ -5718,23 +9894,23 @@ nodes: [[[2, 3], [4, 5]], [0, 1]] 11reserved -Drawbacks +Drawbacks This change would reduce the maximum possible transaction version from the current 127 to 63. In order to bypass the new, lower limit, the extrinsic format would have to change again. -Testing, Security, and Privacy +Testing, Security, and Privacy There is no impact on testing, security or privacy. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility This change would allow Polkadot to support new types of transactions, with the specific "general" transaction type in mind at the time of writing this proposal. -Performance +Performance There is no performance impact. -Ergonomics +Ergonomics The impact to developers and end-users is minimal as it would just be a bitmask update on their part for parsing the extrinsic type along with the version. -Compatibility +Compatibility This change breaks backwards compatiblity because any transaction that is neither signed nor unsigned, but a new transaction type, would be interpreted as having a future extrinsic format version. -Prior Art and References +Prior Art and References The original design was originally proposed in the TransactionExtension PR, which is also the motivation behind this effort. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material Following this change, the "general" transaction type will be introduced as part of the Extrinsic Horizon effort, which will shape future work. (source) Table of Contents @@ -5767,16 +9943,16 @@ nodes: [[[2, 3], [4, 5]], [0, 1]] AuthorsAlex Gheorghe (alexggh) -Summary +Summary Extend the DHT authority discovery records with a signed creation time, so that nodes can determine which record is newer and always decide to prefer the newer records to the old ones. -Motivation +Motivation Currently, we use the Kademlia DHT for storing records regarding the p2p address of an authority discovery key, the problem is that if the nodes decide to change its PeerId/Network key it will publish a new record, however because of the distributed and replicated nature of the DHT there is no way to tell which record is newer so both old PeerId and the new PeerId will live in the network until the old one expires(36h), that creates all sort of problem and leads to the node changing its address not being properly connected for up to 36h. After this RFC, nodes are extended to decide to keep the new record and propagate the new record to nodes that have the old record stored, so in the end all the nodes will converge faster to the new record(in the order of minutes, not 36h) Implementation of the rfc: https://github.com/paritytech/polkadot-sdk/pull/3786. Current issue without this enhacement: https://github.com/paritytech/polkadot-sdk/issues/3673 -Stakeholders +Stakeholders Polkadot node developers. -Explanation +Explanation This RFC heavily relies on the functionalities of the Kademlia DHT already in use by Polkadot. You can find a link to the specification here. In a nutshell, on a specific node the current authority-discovery protocol publishes Kademila DHT records at startup and periodically. The records contain the full address of the node for each authorithy key it owns. The node tries also to find the full address of all authorities in the network by querying the DHT and picking up the first record it finds for each of the authority id it found on chain. @@ -5809,24 +9985,24 @@ You can find a link to the specification Drawbacks +Drawbacks In theory the new protocol creates a bit more traffic on the DHT network, because it waits for DHT records to be received from more than one node, while in the current implementation we just take the first record that we receive and cancel all in-flight requests to other peers. However, because the redundancy factor will be relatively small and this operation happens rarerly, every 10min, this cost is negligible. -Testing, Security, and Privacy +Testing, Security, and Privacy This RFC's implementation https://github.com/paritytech/polkadot-sdk/pull/3786 had been tested on various local test networks and versi. With regard to security the creation time is wrapped inside SignedAuthorityRecord wo it will be signed with the authority id key, so there is no way for other malicious nodes to manipulate this field without the received node observing. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility Irrelevant. -Performance +Performance Irrelevant. -Ergonomics +Ergonomics Irrelevant. -Compatibility +Compatibility The changes are backwards compatible with the existing protocol, so nodes with both the old protocol and newer protocol can exist in the network, this is achieved by the fact that we use protobuf for serializing and deserializing the records, so new fields will be ignore when deserializing with the older protocol and vice-versa when deserializing an old record with the new protocol the new field will be None and the new code accepts this record as being valid. -Prior Art and References +Prior Art and References The enhancements have been inspired by the algorithm specified in here -Unresolved Questions +Unresolved Questions N/A -Future Directions and Related Material +Future Directions and Related Material N/A (source) Table of Contents @@ -5872,23 +10048,23 @@ in order to speed up the time until all nodes have the newest record, nodes can AuthorsJonas Gehrlein & Alistair Stewart -Summary +Summary This RFC proposes a flexible unbonding mechanism for tokens that are locked from staking on the Relay Chain (DOT/KSM), aiming to enhance user convenience without compromising system security. Locking tokens for staking ensures that Polkadot is able to slash tokens backing misbehaving validators. With changing the locking period, we still need to make sure that Polkadot can slash enough tokens to deter misbehaviour. This means that not all tokens can be unbonded immediately, however we can still allow some tokens to be unbonded quickly. The new mechanism leads to a signficantly reduced unbonding time on average, by queuing up new unbonding requests and scaling their unbonding duration relative to the size of the queue. New requests are executed with a minimum of 2 days, when the queue is comparatively empty, to the conventional 28 days, if the sum of requests (in terms of stake) exceed some threshold. In scenarios between these two bounds, the unbonding duration scales proportionately. The new mechanism will never be worse than the current fixed 28 days. In this document we also present an empirical analysis by retrospectively fitting the proposed mechanism to the historic unbonding timeline and show that the average unbonding duration would drastically reduce, while still being sensitive to large unbonding events. Additionally, we discuss implications for UI, UX, and conviction voting. Note: Our proposition solely focuses on the locks imposed from staking. Other locks, such as governance, remain unchanged. Also, this mechanism should not be confused with the already existing feature of FastUnstake, which lets users unstake tokens immediately that have not received rewards for 28 days or longer. As an initial step to gauge its effectiveness and stability, it is recommended to implement and test this model on Kusama before considering its integration into Polkadot, with appropriate adjustments to the parameters. In the following, however, we limit our discussion to Polkadot. -Motivation +Motivation Polkadot has one of the longest unbonding periods among all Proof-of-Stake protocols, because security is the most important goal. Staking on Polkadot is still attractive compared to other protocols because of its above-average staking APY. However the long unbonding period harms usability and deters potential participants that want to contribute to the security of the network. The current length of the unbonding period imposes significant costs for any entity that even wants to perform basic tasks such as a reorganization / consolidation of their stashes, or updating their private key infrastructure. It also limits participation of users that have a large preference for liquidity. The combination of long unbonding periods and high returns has lead to the proliferation of liquid staking, where parachains or centralised exchanges offer users their staked tokens before the 28 days unbonding period is over either in original DOT/KSM form or derivative tokens. Liquid staking is harmless if few tokens are involved but it could result in many validators being selected by a few entities if a large fraction of DOTs were involved. This may lead to centralization (see here for more discussion on threats of liquid staking) and an opportunity for attacks. The new mechanism greatly increases the competitiveness of Polkadot, while maintaining sufficient security. -Stakeholders +Stakeholders Every DOT/KSM token holder -Explanation +Explanation Before diving into the details of how to implement the unbonding queue, we give readers context about why Polkadot has a 28-day unbonding period in the first place. The reason for it is to prevent long-range attacks (LRA) that becomes theoretically possible if more than 1/3 of validators collude. In essence, a LRA describes the inability of users, who disconnect from the consensus at time t0 and reconnects later, to realize that validators which were legitimate at a certain time, say t0 but dropped out in the meantime, are not to be trusted anymore. That means, for example, a user syncing the state could be fooled by trusting validators that fell outside the active set of validators after t0, and are building a competitive and malicious chain (fork). LRAs of longer than 28 days are mitigated by the use of trusted checkpoints, which are assumed to be no more than 28 days old. A new node that syncs Polkadot will start at the checkpoint and look for proofs of finality of later blocks, signed by 2/3 of the validators. In an LRA fork, some of the validator sets may be different but only if 2/3 of some validator set in the last 28 days signed something incorrect. If we detect an LRA of no more than 28 days with the current unbonding period, then we should be able to detect misbehaviour from over 1/3 of validators whose nominators are still bonded. The stake backing these validators is considerable fraction of the total stake (empirically it is 0.287 or so). If we allowed more than this stake to unbond, without checking who it was backing, then the LRA attack might be free of cost for an attacker. The proposed mechansim allows up to half this stake to unbond within 28 days. This halves the amount of tokens that can be slashed, but this is still very high in absolute terms. For example, at the time of writing (19.06.2024) this would translate to around 120 millions DOTs. @@ -5946,23 +10122,23 @@ The analysis can be reproduced or changed to other parameters using Potential Extension In addition to a simple queue, we could add a market component that lets users always unbond from staking at the minimum possible waiting time)(== LOWER_BOUND, e.g., 2 days), by paying a variable fee. To achieve this, it is reasonable to split the total unbonding capacity into two chunks, with the first capacity for the simple queue and the remaining capacity for the fee-based unbonding. By doing so, we allow users to choose whether they want the quickest unbond and paying a dynamic fee or join the simple queue. Setting a capacity restriction for both queues enables us to guarantee a predictable unbonding time in the simple queue, while allowing users with the respective willingness to pay to get out even earlier. The fees are dynamically adjusted and are proportional to the unbonding stake (and thereby expressed in a percentage of the requested unbonding stake). In contrast to a unified queue, this prevents the issue that users paying a fee jump in front of other users not paying a fee, pushing their unbonding time back (which would be bad for UX). The revenue generated could be burned. This extension and further specifications are left out of this RFC, because it adds further complexity and the empirical analysis above suggests that average unbonding times will already be close the LOWER_BOUND, making a more complex design unnecessary. We advise to first implement the discussed mechanism and assess after some experience whether an extension is desirable. -Drawbacks +Drawbacks Lower security for LRAs: Without a doubt, the theoretical security against LRAs decreases. But, as we argue, the attack is still costly enough to deter attacks and the attack is sufficiently theoretical. Here, the benefits outweigh the costs. Griefing attacks: A large holder could pretend to unbond a large amount of their tokens to prevent other users to exit the network earlier. This would, however be costly due to the fact that the holder loses out on staking rewards. The larger the impact on the queue, the higher the costs. In any case it must be noted that the UPPER_BOUND is still 28 days, which means that nominators are never left with a longer unbonding period than currently. There is not enough gain for the attacker to endure this cost. Challenge for Custodians and Liquid Staking Providers: Changing the unbonding time, especially making it flexible, requires entities that offer staking derivatives to rethink and rework their products. -Testing, Security, and Privacy +Testing, Security, and Privacy NA -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility NA -Performance +Performance The authors cannot see any potential impact on performance. -Ergonomics +Ergonomics The authors cannot see any potential impact on ergonomics for developers. We discussed potential impact on UX/UI for users above. -Compatibility +Compatibility The authors cannot see any potential impact on compatibility. This should be assessed by the technical fellows. -Prior Art and References +Prior Art and References Ethereum proposed a similar solution Alistair did some initial write-up @@ -5999,20 +10175,20 @@ The analysis can be reproduced or changed to other parameters using Summary +Summary This RFC proposes a change to the extrinsic format to include a transaction extension version. -Motivation +Motivation The extrinsic format supports to be extended with transaction extensions. These transaction extensions are runtime specific and can be different per chain. Each transaction extension can add data to the extrinsic itself or extend the signed payload. This means that adding a transaction extension is breaking the chain specific extrinsic format. A recent example was the introduction of the CheckMetadatHash to Polkadot and all its system chains. As the extension was adding one byte to the extrinsic, it broke a lot of tooling. By introducing an extra version for the transaction extensions it will be possible to introduce changes to these transaction extensions while still being backwards compatible. Based on the version of the transaction extensions, each chain runtime could decode the extrinsic correctly and also create the correct signed payload. -Stakeholders +Stakeholders Runtime users Runtime devs Wallet devs -Explanation +Explanation RFC84 introduced the extrinsic format 5. The idea is to piggyback onto this change of the extrinsic format to add the extra version for the transaction extensions. If required, this could also come as extrinsic format 6, but 5 is not yet deployed anywhere. The extrinsic format supports the following types of transactions: @@ -6028,25 +10204,25 @@ as extrinsic format 6, but 5 is not yet deployed anywh The Version being a SCALE encoded u8 representing the version of the transaction extensions. In the chain runtime the version can be used to determine which set of transaction extensions should be used to decode and to validate the transaction. -Drawbacks +Drawbacks This adds one byte more to each signed transaction. -Testing, Security, and Privacy +Testing, Security, and Privacy There is no impact on testing, security or privacy. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility This will ensure that changes to the transactions extensions can be done in a backwards compatible way. -Performance +Performance There is no performance impact. -Ergonomics +Ergonomics Runtime developers need to take care of the versioning and ensure to bump as required, so that there are no compatibility breaking changes without a bump of the version. It will also add a little bit more code in the runtime to decode these old versions, but this should be neglectable. -Compatibility +Compatibility When introduced together with extrinsic format version 5 from RFC84, it can be implemented in a backwards compatible way. So, transactions can still be send using the old extrinsic format and decoded by the runtime. -Prior Art and References +Prior Art and References None. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material None. (source) Table of Contents @@ -6083,14 +10259,14 @@ old extrinsic format and decoded by the runtime. AuthorsAdrian Catangiu -Summary +Summary This RFC proposes a new instruction that provides a way to initiate on remote chains, asset transfers which transfer multiple types (teleports, local-reserve, destination-reserve) of assets, using XCM alone. The currently existing instructions are too opinionated and force each XCM asset transfer to a single transfer type (teleport, local-reserve, destination-reserve). This results in inability to combine different types of transfers in single transfer which results in overall poor UX when trying to move assets across chains. -Motivation +Motivation XCM is the de-facto cross-chain messaging protocol within the Polkadot ecosystem, and cross-chain assets transfers is one of its main use-cases. Unfortunately, in its current spec, it does not support initiating on a remote chain, one or more transfers that combine assets with different transfer types. @@ -6112,14 +10288,14 @@ For example, allows single XCM program execution to transfer multiple assets fro Kusama Asset Hub, over the bridge through Polkadot Asset Hub with final destination ParaP on Polkadot. With current XCM, we are limited to doing multiple independent transfers for each individual hop in order to move both "interesting" assets, but also "supporting" assets (used to pay fees). -Stakeholders +Stakeholders Runtime users Runtime devs Wallet devs dApps devs -Explanation +Explanation A new instruction InitiateAssetsTransfer is introduced that initiates an assets transfer from the chain it is executed on, to another chain. The executed transfer is point-to-point (chain-to-chain) with all of the transfer properties specified in the instruction parameters. The instruction also @@ -6307,9 +10483,9 @@ by executing a single XCM message, even though we'll be mixing multiple ).unwrap(); }) }
Vec<u8>
Proof
Validator operators need to pass the their account id when rotating their session keys in a node. This will require updating some high level docs and making users familiar with the slightly changed ergonomics.
Testing of the new changes only requires passing an appropriate owner for the current testing context. The changes to the proof generation and verification got audited to ensure they are correct.
owner
The session key generation is an offchain process and thus, doesn't influence the performance of the chain. Verifying the proof is done on chain as part of the transaction logic for setting the session keys. The verification of the proof is a signature verification number of individual session keys times. As setting the session keys is happening quite rarely, it should not influence the overall system performance.
The interfaces have been optimized to make it as easy as possible to generate the ownership proof.
Introduces a new version of the SessionKeys runtime api. Thus, nodes should be updated before a runtime is enacted that contains these changes otherwise they will fail to generate session keys. The RPC that exists around this runtime api needs to be updated to support passing the account id and for returning the ownership proof alongside the public session keys.
UIs would need to be updated to support the new RPC and the changed on chain logic.
Substrate implementation of the RFC.
The Fellowship Manifesto states that members should receive a monthly allowance on par with gross income in OECD countries. This RFC proposes concrete amounts.
One motivation for the Technical Fellowship is to provide an incentive mechanism that can induct and retain technical talent for the continued progress of the network.
In order for members to uphold their commitment to the network, they should receive support to @@ -4996,12 +9172,12 @@ on par with a full-time job. Providing a livable wage to those making such contr pragmatic to work full-time on Polkadot.
Note: Goals of the Fellowship, expectations for each Dan, and conditions for promotion and demotion are all explained in the Manifesto. This RFC is only to propose concrete values for allowances.
This RFC proposes agreeing on salaries relative to a single level, the III Dan. As such, changes to the amount or asset used would only be on a single value, and all others would adjust relatively. A III Dan is someone whose contributions match the expectations of a full-time individual contributor. @@ -5061,19 +9237,19 @@ other hand, more people will likely join the Fellowship in the coming years.
Updates to these levels, whether relative ratios, the asset used, or the amount, shall be done via RFC.
By not using DOT for payment, the protocol relies on the stability of other assets and the ability to acquire them. However, the asset of choice can be changed in the future.
N/A.
When two peers connect to each other, they open (amongst other things) a so-called "notifications protocol" substream dedicated to gossiping transactions to each other.
Each notification on this substream currently consists in a SCALE-encoded Vec<Transaction> where Transaction is defined in the runtime.
Vec<Transaction>
Transaction
This RFC proposes to modify the format of the notification to become (Compact(1), Transaction). This maintains backwards compatibility, as this new format decodes as a Vec of length equal to 1.
(Compact(1), Transaction)
Vec
There exists three motivations behind this change:
It makes the implementation way more straight-forward by not having to repeat code related to back-pressure. See explanations below.
Low-level developers.
To give an example, if you send one notification with three transactions, the bytes that are sent on the wire are:
concat( leb128(total-size-in-bytes-of-the-rest), @@ -5153,23 +9329,23 @@ A SCALE-compact encoded 1 is one byte of value 4. In o This is equivalent to forcing the Vec<Transaction> to always have a length of 1, and I expect the Substrate implementation to simply modify the sending side to add a for loop that sends one notification per item in the Vec. As explained in the motivation section, this allows extracting scale(transaction) items without having to know how to decode them. By "flattening" the two-steps hierarchy, an implementation only needs to back-pressure individual notifications rather than back-pressure notifications and transactions within notifications. -Drawbacks +Drawbacks This RFC chooses to maintain backwards compatibility at the cost of introducing a very small wart (the Compact(1)). An alternative could be to introduce a new version of the transactions notifications protocol that sends one Transaction per notification, but this is significantly more complicated to implement and can always be done later in case the Compact(1) is bothersome. -Testing, Security, and Privacy +Testing, Security, and Privacy Irrelevant. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance Irrelevant. -Ergonomics +Ergonomics Irrelevant. -Compatibility +Compatibility The change is backwards compatible if done in two steps: modify the sender to always send one transaction per notification, then, after a while, modify the receiver to enforce the new format. -Prior Art and References +Prior Art and References Irrelevant. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material None. This is a simple isolated change. (source) Table of Contents @@ -5209,20 +9385,20 @@ This is equivalent to forcing the Vec<Transaction> to always AuthorsPierre Krieger -Summary +Summary This RFC proposes to make the mechanism of RFC #8 more generic by introducing the concept of "capabilities". Implementations can implement certain "capabilities", such as serving old block headers or being a parachain bootnode. The discovery mechanism of RFC #8 is extended to be able to discover nodes of specific capabilities. -Motivation +Motivation The Polkadot peer-to-peer network is made of nodes. Not all these nodes are equal. Some nodes store only the headers of recent blocks, some nodes store all the block headers and bodies since the genesis, some nodes store the storage of all blocks since the genesis, and so on. It is currently not possible to know ahead of time (without connecting to it and asking) which nodes have which data available, and it is not easily possible to build a list of nodes that have a specific piece of data available. If you want to download for example the header of block 500, you have to connect to a randomly-chosen node, ask it for block 500, and if it says that it doesn't have the block, disconnect and try another randomly-chosen node. In certain situations such as downloading the storage of old blocks, nodes that have the information are relatively rare, and finding through trial and error a node that has the data can take a long time. This RFC attempts to solve this problem by giving the possibility to build a list of nodes that are capable of serving specific data. -Stakeholders +Stakeholders Low-level client developers. People interested in accessing the archive of the chain. -Explanation +Explanation Reading RFC #8 first might help with comprehension, as this RFC is very similar. Please keep in mind while reading that everything below applies for both relay chains and parachains, except mentioned otherwise. Capabilities @@ -5258,30 +9434,30 @@ If blocks pruning is enabled and the chain is a relay chain, then Substrate unfo Implementations that have the head of the chain provider capability do not register themselves as providers, but instead are the nodes that participate in the main DHT. In other words, they are the nodes that serve requests of the /<genesis_hash>/kad protocol. Any implementation that isn't a head of the chain provider (read: light clients) must not participate in the main DHT. This is already presently the case. Implementations must not participate in the main DHT if they don't fulfill the capability yet. For example, a node that is still in the process of warp syncing must not participate in the main DHT. However, assuming that warp syncing doesn't last more than a few seconds, it is acceptable to ignore this requirement in order to avoid complicating implementations too much. -Drawbacks +Drawbacks None that I can see. -Testing, Security, and Privacy +Testing, Security, and Privacy The content of this section is basically the same as the one in RFC 8. This mechanism doesn't add or remove any security by itself, as it relies on existing mechanisms. Due to the way Kademlia works, it would become the responsibility of the 20 Polkadot nodes whose sha256(peer_id) is closest to the key (described in the explanations section) to store the list of nodes that have specific capabilities. Furthermore, when a large number of providers are registered, only the providers closest to the key are kept, up to a certain implementation-defined limit. For this reason, an attacker can abuse this mechanism by randomly generating libp2p PeerIds until they find the 20 entries closest to the key representing the target capability. They are then in control of the list of nodes with that capability. While doing this can in no way be actually harmful, it could lead to eclipse attacks. Because the key changes periodically and isn't predictable, and assuming that the Polkadot DHT is sufficiently large, it is not realistic for an attack like this to be maintained in the long term. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance The DHT mechanism generally has a low overhead, especially given that publishing providers is done only every 24 hours. Doing a Kademlia iterative query then sending a provider record shouldn't take more than around 50 kiB in total of bandwidth for the parachain bootnode. Assuming 1000 nodes with a specific capability, the 20 Polkadot full nodes corresponding to that capability will each receive a sudden spike of a few megabytes of networking traffic when the key rotates. Again, this is relatively negligible. If this becomes a problem, one can add a random delay before a node registers itself to be the provider of the key corresponding to BabeApi_next_epoch. Maybe the biggest uncertainty is the traffic that the 20 Polkadot full nodes will receive from light clients that desire knowing the nodes with a capability. If this every becomes a problem, this value of 20 is an arbitrary constant that can be increased for more redundancy. -Ergonomics +Ergonomics Irrelevant. -Compatibility +Compatibility Irrelevant. -Prior Art and References +Prior Art and References Unknown. -Unresolved Questions +Unresolved Questions While it fundamentally doesn't change much to this RFC, using BabeApi_currentEpoch and BabeApi_nextEpoch might be inappropriate. I'm not familiar enough with good practices within the runtime to have an opinion here. Should it be an entirely new pallet? -Future Directions and Related Material +Future Directions and Related Material This RFC would make it possible to reliably discover archive nodes, which would make it possible to reliably send archive node requests, something that isn't currently possible. This could solve the problem of finding archive RPC node providers by migrating archive-related request to using the native peer-to-peer protocol rather than JSON-RPC. If we ever decide to break backwards compatibility, we could divide the "history" and "archive" capabilities in two, between nodes capable of serving older blocks and nodes capable of serving newer blocks. We could even add to the peer-to-peer network nodes that are only capable of serving older blocks (by reading from a database) but do not participate in the head of the chain, and that just exist for historical purposes. @@ -5330,12 +9506,12 @@ We could even add to the peer-to-peer network nodes that are only capable of ser AuthorsZondax AG, Parity Technologies -Summary +Summary To interact with chains in the Polkadot ecosystem it is required to know how transactions are encoded and how to read state. For doing this, Polkadot-SDK, the framework used by most of the chains in the Polkadot ecosystem, exposes metadata about the runtime to the outside. UIs, wallets, and others can use this metadata to interact with these chains. This makes the metadata a crucial piece of the transaction encoding as users are relying on the interacting software to encode the transactions in the correct format. It gets even more important when the user signs the transaction in an offline wallet, as the device by its nature cannot get access to the metadata without relying on the online wallet to provide it. This makes it so that the offline wallet needs to trust an online party, deeming the security assumptions of the offline devices, mute. This RFC proposes a way for offline wallets to leverage metadata, within the constraints of these. The design idea is that the metadata is chunked and these chunks are put into a merkle tree. The root hash of this merkle tree represents the metadata. The offline wallets can use the root hash to decode transactions by getting proofs for the individual chunks of the metadata. This root hash is also included in the signed data of the transaction (but not sent as part of the transaction). The runtime is then including its known metadata root hash when verifying the transaction. If the metadata root hash known by the runtime differs from the one that the offline wallet used, it very likely means that the online wallet provided some fake data and the verification of the transaction fails. Users depend on offline wallets to correctly display decoded transactions before signing. With merkleized metadata, they can be assured of the transaction's legitimacy, as incorrect transactions will be rejected by the runtime. -Motivation +Motivation Polkadot's innovative design (both relay chain and parachains) present the ability to developers to upgrade their network as frequently as they need. These systems manage to have integrations working after the upgrades with the help of FRAME Metadata. This Metadata, which is in the order of half a MiB for most Polkadot-SDK chains, completely describes chain interfaces and properties. Securing this metadata is key for users to be able to interact with the Polkadot-SDK chain in the expected way. On the other hand, offline wallets provide a secure way for Blockchain users to hold their own keys (some do a better job than others). These devices seldomly get upgraded, usually account for one particular network and hold very small internal memories. Currently in the Polkadot ecosystem there is no secure way of having these offline devices know the latest Metadata of the Polkadot-SDK chain they are interacting with. This results in a plethora of similar yet slightly different offline wallets for all different Polkadot-SDK chains, as well as the impediment of keeping these regularly updated, thus not fully leveraging Polkadot-SDK’s unique forkless upgrade feature. The two main reasons why this is not possible today are: @@ -5344,7 +9520,7 @@ We could even add to the peer-to-peer network nodes that are only capable of ser Metadata is not authenticated. Even if there was enough space on offline devices to hold the metadata, the user would be trusting the entity providing this metadata to the hardware wallet. In the Polkadot ecosystem, this is how currently Polkadot Vault works. This RFC proposes a solution to make FRAME Metadata compatible with offline signers in a secure way. As it leverages FRAME Metadata, it does not only ensure that offline devices can always keep up to date with every FRAME based chain, but also that every offline wallet will be compatible with all FRAME based chains, avoiding the need of per-chain implementations. -Requirements +Requirements Metadata's integrity MUST be preserved. If any compromise were to happen, extrinsics sent with compromised metadata SHOULD fail. Metadata information that could be used in signable extrinsic decoding MAY be included in digest, yet its inclusion MUST be indicated in signed extensions. @@ -5362,14 +9538,14 @@ We could even add to the peer-to-peer network nodes that are only capable of ser Chunks handling mechanism SHOULD support chunks being sent in any order without memory utilization overhead; Unused enum variants MUST be stripped (this has great impact on transmitted metadata size; examples: era enum, enum with all calls for call batching). -Stakeholders +Stakeholders Runtime implementors UI/wallet implementors Offline wallet implementors The idea for this RFC was brought up by runtime implementors and was extensively discussed with offline wallet implementors. It was designed in such a way that it can work easily with the existing offline wallet solutions in the Polkadot ecosystem. -Explanation +Explanation The FRAME metadata provides a wide range of information about a FRAME based runtime. It contains information about the pallets, the calls per pallet, the storage entries per pallet, runtime APIs, and type information about most of the types that are used in the runtime. For decoding extrinsics on an offline wallet, what is mainly required is type information. Most of the other information in the FRAME metadata is actually not required for decoding extrinsics and thus it can be removed. Therefore, the following is a proposal on a custom representation of the metadata and how this custom metadata is chunked, ensuring that only the needed chunks required for decoding a particular extrinsic are sent to the offline wallet. The necessary information to transform the FRAME metadata type information into the type information presented in this RFC will be provided. However, not every single detail on how to convert from FRAME metadata into the RFC type information is described. First, the MetadataDigest is introduced. After that, ExtrinsicMetadata is covered and finally the actual format of the type information. Then pruning of unrelated type information is covered and how to generate the TypeRefs. In the latest step, merkle tree calculation is explained. Metadata digest @@ -5640,23 +9816,23 @@ nodes: [[[2, 3], [4, 5]], [0, 1]] Included in the extrinsic is u8, the "mode". The mode is either 0 which means to not include the metadata hash in the signed data or the mode is 1 to include the metadata hash in V1. Included in the signed data is an Option<[u8; 32]>. Depending on the mode the value is either None or Some(metadata_hash). -Drawbacks +Drawbacks The chunking may not be the optimal case for every kind of offline wallet. -Testing, Security, and Privacy +Testing, Security, and Privacy All implementations are required to strictly follow the RFC to generate the metadata hash. This includes which hash function to use and how to construct the metadata types tree. So, all implementations are following the same security criteria. As the chains will calculate the metadata hash at compile time, the build process needs to be trusted. However, this is already a solved problem in the Polkadot ecosystem by using reproducible builds. So, anyone can rebuild a chain runtime to ensure that a proposal is actually containing the changes as advertised. Implementations can also be tested easily against each other by taking some metadata and ensuring that they all come to the same metadata hash. Privacy of users should also not be impacted. This assumes that wallets will generate the metadata hash locally and don't leak any information to third party services about which chunks a user will send to their offline wallet. Besides that, there is no leak of private information as getting the raw metadata from the chain is an operation that is done by almost everyone. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance There should be no measurable impact on performance to Polkadot or any other chain using this feature. The metadata root hash is calculated at compile time and at runtime it is optionally used when checking the signature of a transaction. This means that at runtime no performance heavy operations are done. -Ergonomics & Compatibility +Ergonomics & Compatibility The proposal alters the way a transaction is built, signed, and verified. So, this imposes some required changes to any kind of developer who wants to construct transactions for Polkadot or any chain using this feature. As the developer can pass 0 for disabling the verification of the metadata root hash, it can be easily ignored. -Prior Art and References +Prior Art and References RFC 46 produced by the Alzymologist team is a previous work reference that goes in this direction as well. On other ecosystems, there are other solutions to the problem of trusted signing. Cosmos for example has a standardized way of transforming a transaction into some textual representation and this textual representation is included in the signed data. Basically achieving the same as what the RFC proposes, but it requires that for every transaction applied in a block, every node in the network always has to generate this textual representation to ensure the transaction signature is valid. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material Does it work with all kind of offline wallets? Generic types currently appear multiple times in the metadata with each instantiation. It could be may be useful to have generic type only once in the metadata and declare the generic parameters at their instantiation. @@ -5694,20 +9870,20 @@ nodes: [[[2, 3], [4, 5]], [0, 1]] AuthorsGeorge Pisaltu -Summary +Summary This RFC proposes a change to the extrinsic format to incorporate a new transaction type, the "general" transaction. -Motivation +Motivation "General" transactions, a new type of transaction that this RFC aims to support, are transactions which obey the runtime's extensions and have according extension data yet do not have hard-coded signatures. They are first described in Extrinsic Horizon and supported in 3685. They enable users to authorize origins in new, more flexible ways (e.g. ZK proofs, mutations over pre-authenticated origins). As of now, all transactions are limited to the account signing model for origin authorization and any additional origin changes happen in extrinsic logic, which cannot leverage the validation process of extensions. An example of a use case for such an extension would be sponsoring the transaction fee for some other user. A new extension would be put in place to verify that a part of the initial payload was signed by the author under who the extrinsic should run and change the origin, but the payment for the whole transaction should be handled under a sponsor's account. A POC for this can be found in 3712. The new "general" transaction type would coexist with both current transaction types for a while and, therefore, the current number of supported transaction types, capped at 2, is insufficient. A new extrinsic type must be introduced alongside the current signed and unsigned types. Currently, an encoded extrinsic's first byte indicate the type of extrinsic using the most significant bit - 0 for unsigned, 1 for signed - and the 7 following bits indicate the extrinsic format version, which has been equal to 4 for a long time. By taking one bit from the extrinsic format version encoding, we can support 2 additional extrinsic types while also having a minimal impact on our capability to extend and change the extrinsic format in the future. -Stakeholders +Stakeholders Runtime users Runtime devs Wallet devs -Explanation +Explanation An extrinsic is currently encoded as one byte to identify the extrinsic type and version. This RFC aims to change the interpretation of this byte regarding the reserved bits for the extrinsic type and version. In the following explanation, bits represented using T make up the extrinsic type and bits represented using V make up the extrinsic version. Currently, the bit allocation within the leading encoded byte is 0bTVVV_VVVV. In practice in the Polkadot ecosystem, the leading byte would be 0bT000_0100 as the version has been equal to 4 for a long time. This RFC proposes for the bit allocation to change to 0bTTVV_VVVV. As a result, the extrinsic format version will be bumped to 5 and the extrinsic type bit representation would change as follows: @@ -5718,23 +9894,23 @@ nodes: [[[2, 3], [4, 5]], [0, 1]] 11reserved -Drawbacks +Drawbacks This change would reduce the maximum possible transaction version from the current 127 to 63. In order to bypass the new, lower limit, the extrinsic format would have to change again. -Testing, Security, and Privacy +Testing, Security, and Privacy There is no impact on testing, security or privacy. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility This change would allow Polkadot to support new types of transactions, with the specific "general" transaction type in mind at the time of writing this proposal. -Performance +Performance There is no performance impact. -Ergonomics +Ergonomics The impact to developers and end-users is minimal as it would just be a bitmask update on their part for parsing the extrinsic type along with the version. -Compatibility +Compatibility This change breaks backwards compatiblity because any transaction that is neither signed nor unsigned, but a new transaction type, would be interpreted as having a future extrinsic format version. -Prior Art and References +Prior Art and References The original design was originally proposed in the TransactionExtension PR, which is also the motivation behind this effort. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material Following this change, the "general" transaction type will be introduced as part of the Extrinsic Horizon effort, which will shape future work. (source) Table of Contents @@ -5767,16 +9943,16 @@ nodes: [[[2, 3], [4, 5]], [0, 1]] AuthorsAlex Gheorghe (alexggh) -Summary +Summary Extend the DHT authority discovery records with a signed creation time, so that nodes can determine which record is newer and always decide to prefer the newer records to the old ones. -Motivation +Motivation Currently, we use the Kademlia DHT for storing records regarding the p2p address of an authority discovery key, the problem is that if the nodes decide to change its PeerId/Network key it will publish a new record, however because of the distributed and replicated nature of the DHT there is no way to tell which record is newer so both old PeerId and the new PeerId will live in the network until the old one expires(36h), that creates all sort of problem and leads to the node changing its address not being properly connected for up to 36h. After this RFC, nodes are extended to decide to keep the new record and propagate the new record to nodes that have the old record stored, so in the end all the nodes will converge faster to the new record(in the order of minutes, not 36h) Implementation of the rfc: https://github.com/paritytech/polkadot-sdk/pull/3786. Current issue without this enhacement: https://github.com/paritytech/polkadot-sdk/issues/3673 -Stakeholders +Stakeholders Polkadot node developers. -Explanation +Explanation This RFC heavily relies on the functionalities of the Kademlia DHT already in use by Polkadot. You can find a link to the specification here. In a nutshell, on a specific node the current authority-discovery protocol publishes Kademila DHT records at startup and periodically. The records contain the full address of the node for each authorithy key it owns. The node tries also to find the full address of all authorities in the network by querying the DHT and picking up the first record it finds for each of the authority id it found on chain. @@ -5809,24 +9985,24 @@ You can find a link to the specification Drawbacks +Drawbacks In theory the new protocol creates a bit more traffic on the DHT network, because it waits for DHT records to be received from more than one node, while in the current implementation we just take the first record that we receive and cancel all in-flight requests to other peers. However, because the redundancy factor will be relatively small and this operation happens rarerly, every 10min, this cost is negligible. -Testing, Security, and Privacy +Testing, Security, and Privacy This RFC's implementation https://github.com/paritytech/polkadot-sdk/pull/3786 had been tested on various local test networks and versi. With regard to security the creation time is wrapped inside SignedAuthorityRecord wo it will be signed with the authority id key, so there is no way for other malicious nodes to manipulate this field without the received node observing. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility Irrelevant. -Performance +Performance Irrelevant. -Ergonomics +Ergonomics Irrelevant. -Compatibility +Compatibility The changes are backwards compatible with the existing protocol, so nodes with both the old protocol and newer protocol can exist in the network, this is achieved by the fact that we use protobuf for serializing and deserializing the records, so new fields will be ignore when deserializing with the older protocol and vice-versa when deserializing an old record with the new protocol the new field will be None and the new code accepts this record as being valid. -Prior Art and References +Prior Art and References The enhancements have been inspired by the algorithm specified in here -Unresolved Questions +Unresolved Questions N/A -Future Directions and Related Material +Future Directions and Related Material N/A (source) Table of Contents @@ -5872,23 +10048,23 @@ in order to speed up the time until all nodes have the newest record, nodes can AuthorsJonas Gehrlein & Alistair Stewart -Summary +Summary This RFC proposes a flexible unbonding mechanism for tokens that are locked from staking on the Relay Chain (DOT/KSM), aiming to enhance user convenience without compromising system security. Locking tokens for staking ensures that Polkadot is able to slash tokens backing misbehaving validators. With changing the locking period, we still need to make sure that Polkadot can slash enough tokens to deter misbehaviour. This means that not all tokens can be unbonded immediately, however we can still allow some tokens to be unbonded quickly. The new mechanism leads to a signficantly reduced unbonding time on average, by queuing up new unbonding requests and scaling their unbonding duration relative to the size of the queue. New requests are executed with a minimum of 2 days, when the queue is comparatively empty, to the conventional 28 days, if the sum of requests (in terms of stake) exceed some threshold. In scenarios between these two bounds, the unbonding duration scales proportionately. The new mechanism will never be worse than the current fixed 28 days. In this document we also present an empirical analysis by retrospectively fitting the proposed mechanism to the historic unbonding timeline and show that the average unbonding duration would drastically reduce, while still being sensitive to large unbonding events. Additionally, we discuss implications for UI, UX, and conviction voting. Note: Our proposition solely focuses on the locks imposed from staking. Other locks, such as governance, remain unchanged. Also, this mechanism should not be confused with the already existing feature of FastUnstake, which lets users unstake tokens immediately that have not received rewards for 28 days or longer. As an initial step to gauge its effectiveness and stability, it is recommended to implement and test this model on Kusama before considering its integration into Polkadot, with appropriate adjustments to the parameters. In the following, however, we limit our discussion to Polkadot. -Motivation +Motivation Polkadot has one of the longest unbonding periods among all Proof-of-Stake protocols, because security is the most important goal. Staking on Polkadot is still attractive compared to other protocols because of its above-average staking APY. However the long unbonding period harms usability and deters potential participants that want to contribute to the security of the network. The current length of the unbonding period imposes significant costs for any entity that even wants to perform basic tasks such as a reorganization / consolidation of their stashes, or updating their private key infrastructure. It also limits participation of users that have a large preference for liquidity. The combination of long unbonding periods and high returns has lead to the proliferation of liquid staking, where parachains or centralised exchanges offer users their staked tokens before the 28 days unbonding period is over either in original DOT/KSM form or derivative tokens. Liquid staking is harmless if few tokens are involved but it could result in many validators being selected by a few entities if a large fraction of DOTs were involved. This may lead to centralization (see here for more discussion on threats of liquid staking) and an opportunity for attacks. The new mechanism greatly increases the competitiveness of Polkadot, while maintaining sufficient security. -Stakeholders +Stakeholders Every DOT/KSM token holder -Explanation +Explanation Before diving into the details of how to implement the unbonding queue, we give readers context about why Polkadot has a 28-day unbonding period in the first place. The reason for it is to prevent long-range attacks (LRA) that becomes theoretically possible if more than 1/3 of validators collude. In essence, a LRA describes the inability of users, who disconnect from the consensus at time t0 and reconnects later, to realize that validators which were legitimate at a certain time, say t0 but dropped out in the meantime, are not to be trusted anymore. That means, for example, a user syncing the state could be fooled by trusting validators that fell outside the active set of validators after t0, and are building a competitive and malicious chain (fork). LRAs of longer than 28 days are mitigated by the use of trusted checkpoints, which are assumed to be no more than 28 days old. A new node that syncs Polkadot will start at the checkpoint and look for proofs of finality of later blocks, signed by 2/3 of the validators. In an LRA fork, some of the validator sets may be different but only if 2/3 of some validator set in the last 28 days signed something incorrect. If we detect an LRA of no more than 28 days with the current unbonding period, then we should be able to detect misbehaviour from over 1/3 of validators whose nominators are still bonded. The stake backing these validators is considerable fraction of the total stake (empirically it is 0.287 or so). If we allowed more than this stake to unbond, without checking who it was backing, then the LRA attack might be free of cost for an attacker. The proposed mechansim allows up to half this stake to unbond within 28 days. This halves the amount of tokens that can be slashed, but this is still very high in absolute terms. For example, at the time of writing (19.06.2024) this would translate to around 120 millions DOTs. @@ -5946,23 +10122,23 @@ The analysis can be reproduced or changed to other parameters using Potential Extension In addition to a simple queue, we could add a market component that lets users always unbond from staking at the minimum possible waiting time)(== LOWER_BOUND, e.g., 2 days), by paying a variable fee. To achieve this, it is reasonable to split the total unbonding capacity into two chunks, with the first capacity for the simple queue and the remaining capacity for the fee-based unbonding. By doing so, we allow users to choose whether they want the quickest unbond and paying a dynamic fee or join the simple queue. Setting a capacity restriction for both queues enables us to guarantee a predictable unbonding time in the simple queue, while allowing users with the respective willingness to pay to get out even earlier. The fees are dynamically adjusted and are proportional to the unbonding stake (and thereby expressed in a percentage of the requested unbonding stake). In contrast to a unified queue, this prevents the issue that users paying a fee jump in front of other users not paying a fee, pushing their unbonding time back (which would be bad for UX). The revenue generated could be burned. This extension and further specifications are left out of this RFC, because it adds further complexity and the empirical analysis above suggests that average unbonding times will already be close the LOWER_BOUND, making a more complex design unnecessary. We advise to first implement the discussed mechanism and assess after some experience whether an extension is desirable. -Drawbacks +Drawbacks Lower security for LRAs: Without a doubt, the theoretical security against LRAs decreases. But, as we argue, the attack is still costly enough to deter attacks and the attack is sufficiently theoretical. Here, the benefits outweigh the costs. Griefing attacks: A large holder could pretend to unbond a large amount of their tokens to prevent other users to exit the network earlier. This would, however be costly due to the fact that the holder loses out on staking rewards. The larger the impact on the queue, the higher the costs. In any case it must be noted that the UPPER_BOUND is still 28 days, which means that nominators are never left with a longer unbonding period than currently. There is not enough gain for the attacker to endure this cost. Challenge for Custodians and Liquid Staking Providers: Changing the unbonding time, especially making it flexible, requires entities that offer staking derivatives to rethink and rework their products. -Testing, Security, and Privacy +Testing, Security, and Privacy NA -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility NA -Performance +Performance The authors cannot see any potential impact on performance. -Ergonomics +Ergonomics The authors cannot see any potential impact on ergonomics for developers. We discussed potential impact on UX/UI for users above. -Compatibility +Compatibility The authors cannot see any potential impact on compatibility. This should be assessed by the technical fellows. -Prior Art and References +Prior Art and References Ethereum proposed a similar solution Alistair did some initial write-up @@ -5999,20 +10175,20 @@ The analysis can be reproduced or changed to other parameters using Summary +Summary This RFC proposes a change to the extrinsic format to include a transaction extension version. -Motivation +Motivation The extrinsic format supports to be extended with transaction extensions. These transaction extensions are runtime specific and can be different per chain. Each transaction extension can add data to the extrinsic itself or extend the signed payload. This means that adding a transaction extension is breaking the chain specific extrinsic format. A recent example was the introduction of the CheckMetadatHash to Polkadot and all its system chains. As the extension was adding one byte to the extrinsic, it broke a lot of tooling. By introducing an extra version for the transaction extensions it will be possible to introduce changes to these transaction extensions while still being backwards compatible. Based on the version of the transaction extensions, each chain runtime could decode the extrinsic correctly and also create the correct signed payload. -Stakeholders +Stakeholders Runtime users Runtime devs Wallet devs -Explanation +Explanation RFC84 introduced the extrinsic format 5. The idea is to piggyback onto this change of the extrinsic format to add the extra version for the transaction extensions. If required, this could also come as extrinsic format 6, but 5 is not yet deployed anywhere. The extrinsic format supports the following types of transactions: @@ -6028,25 +10204,25 @@ as extrinsic format 6, but 5 is not yet deployed anywh The Version being a SCALE encoded u8 representing the version of the transaction extensions. In the chain runtime the version can be used to determine which set of transaction extensions should be used to decode and to validate the transaction. -Drawbacks +Drawbacks This adds one byte more to each signed transaction. -Testing, Security, and Privacy +Testing, Security, and Privacy There is no impact on testing, security or privacy. -Performance, Ergonomics, and Compatibility +Performance, Ergonomics, and Compatibility This will ensure that changes to the transactions extensions can be done in a backwards compatible way. -Performance +Performance There is no performance impact. -Ergonomics +Ergonomics Runtime developers need to take care of the versioning and ensure to bump as required, so that there are no compatibility breaking changes without a bump of the version. It will also add a little bit more code in the runtime to decode these old versions, but this should be neglectable. -Compatibility +Compatibility When introduced together with extrinsic format version 5 from RFC84, it can be implemented in a backwards compatible way. So, transactions can still be send using the old extrinsic format and decoded by the runtime. -Prior Art and References +Prior Art and References None. -Unresolved Questions +Unresolved Questions None. -Future Directions and Related Material +Future Directions and Related Material None. (source) Table of Contents @@ -6083,14 +10259,14 @@ old extrinsic format and decoded by the runtime. AuthorsAdrian Catangiu -Summary +Summary This RFC proposes a new instruction that provides a way to initiate on remote chains, asset transfers which transfer multiple types (teleports, local-reserve, destination-reserve) of assets, using XCM alone. The currently existing instructions are too opinionated and force each XCM asset transfer to a single transfer type (teleport, local-reserve, destination-reserve). This results in inability to combine different types of transfers in single transfer which results in overall poor UX when trying to move assets across chains. -Motivation +Motivation XCM is the de-facto cross-chain messaging protocol within the Polkadot ecosystem, and cross-chain assets transfers is one of its main use-cases. Unfortunately, in its current spec, it does not support initiating on a remote chain, one or more transfers that combine assets with different transfer types. @@ -6112,14 +10288,14 @@ For example, allows single XCM program execution to transfer multiple assets fro Kusama Asset Hub, over the bridge through Polkadot Asset Hub with final destination ParaP on Polkadot. With current XCM, we are limited to doing multiple independent transfers for each individual hop in order to move both "interesting" assets, but also "supporting" assets (used to pay fees). -Stakeholders +Stakeholders Runtime users Runtime devs Wallet devs dApps devs -Explanation +Explanation A new instruction InitiateAssetsTransfer is introduced that initiates an assets transfer from the chain it is executed on, to another chain. The executed transfer is point-to-point (chain-to-chain) with all of the transfer properties specified in the instruction parameters. The instruction also @@ -6307,9 +10483,9 @@ by executing a single XCM message, even though we'll be mixing multiple ).unwrap(); }) }
4
for
As explained in the motivation section, this allows extracting scale(transaction) items without having to know how to decode them.
scale(transaction)
By "flattening" the two-steps hierarchy, an implementation only needs to back-pressure individual notifications rather than back-pressure notifications and transactions within notifications.
This RFC chooses to maintain backwards compatibility at the cost of introducing a very small wart (the Compact(1)).
Compact(1)
An alternative could be to introduce a new version of the transactions notifications protocol that sends one Transaction per notification, but this is significantly more complicated to implement and can always be done later in case the Compact(1) is bothersome.
The change is backwards compatible if done in two steps: modify the sender to always send one transaction per notification, then, after a while, modify the receiver to enforce the new format.
None. This is a simple isolated change.
This RFC proposes to make the mechanism of RFC #8 more generic by introducing the concept of "capabilities".
Implementations can implement certain "capabilities", such as serving old block headers or being a parachain bootnode.
The discovery mechanism of RFC #8 is extended to be able to discover nodes of specific capabilities.
The Polkadot peer-to-peer network is made of nodes. Not all these nodes are equal. Some nodes store only the headers of recent blocks, some nodes store all the block headers and bodies since the genesis, some nodes store the storage of all blocks since the genesis, and so on.
It is currently not possible to know ahead of time (without connecting to it and asking) which nodes have which data available, and it is not easily possible to build a list of nodes that have a specific piece of data available.
If you want to download for example the header of block 500, you have to connect to a randomly-chosen node, ask it for block 500, and if it says that it doesn't have the block, disconnect and try another randomly-chosen node. In certain situations such as downloading the storage of old blocks, nodes that have the information are relatively rare, and finding through trial and error a node that has the data can take a long time.
This RFC attempts to solve this problem by giving the possibility to build a list of nodes that are capable of serving specific data.
Low-level client developers. People interested in accessing the archive of the chain.
Reading RFC #8 first might help with comprehension, as this RFC is very similar.
Please keep in mind while reading that everything below applies for both relay chains and parachains, except mentioned otherwise.
Implementations that have the head of the chain provider capability do not register themselves as providers, but instead are the nodes that participate in the main DHT. In other words, they are the nodes that serve requests of the /<genesis_hash>/kad protocol.
/<genesis_hash>/kad
Any implementation that isn't a head of the chain provider (read: light clients) must not participate in the main DHT. This is already presently the case.
Implementations must not participate in the main DHT if they don't fulfill the capability yet. For example, a node that is still in the process of warp syncing must not participate in the main DHT. However, assuming that warp syncing doesn't last more than a few seconds, it is acceptable to ignore this requirement in order to avoid complicating implementations too much.
None that I can see.
The content of this section is basically the same as the one in RFC 8.
This mechanism doesn't add or remove any security by itself, as it relies on existing mechanisms.
Due to the way Kademlia works, it would become the responsibility of the 20 Polkadot nodes whose sha256(peer_id) is closest to the key (described in the explanations section) to store the list of nodes that have specific capabilities. Furthermore, when a large number of providers are registered, only the providers closest to the key are kept, up to a certain implementation-defined limit.
sha256(peer_id)
For this reason, an attacker can abuse this mechanism by randomly generating libp2p PeerIds until they find the 20 entries closest to the key representing the target capability. They are then in control of the list of nodes with that capability. While doing this can in no way be actually harmful, it could lead to eclipse attacks.
Because the key changes periodically and isn't predictable, and assuming that the Polkadot DHT is sufficiently large, it is not realistic for an attack like this to be maintained in the long term.
Assuming 1000 nodes with a specific capability, the 20 Polkadot full nodes corresponding to that capability will each receive a sudden spike of a few megabytes of networking traffic when the key rotates. Again, this is relatively negligible. If this becomes a problem, one can add a random delay before a node registers itself to be the provider of the key corresponding to BabeApi_next_epoch.
Maybe the biggest uncertainty is the traffic that the 20 Polkadot full nodes will receive from light clients that desire knowing the nodes with a capability. If this every becomes a problem, this value of 20 is an arbitrary constant that can be increased for more redundancy.
Unknown.
This RFC would make it possible to reliably discover archive nodes, which would make it possible to reliably send archive node requests, something that isn't currently possible. This could solve the problem of finding archive RPC node providers by migrating archive-related request to using the native peer-to-peer protocol rather than JSON-RPC.
If we ever decide to break backwards compatibility, we could divide the "history" and "archive" capabilities in two, between nodes capable of serving older blocks and nodes capable of serving newer blocks. We could even add to the peer-to-peer network nodes that are only capable of serving older blocks (by reading from a database) but do not participate in the head of the chain, and that just exist for historical purposes.
To interact with chains in the Polkadot ecosystem it is required to know how transactions are encoded and how to read state. For doing this, Polkadot-SDK, the framework used by most of the chains in the Polkadot ecosystem, exposes metadata about the runtime to the outside. UIs, wallets, and others can use this metadata to interact with these chains. This makes the metadata a crucial piece of the transaction encoding as users are relying on the interacting software to encode the transactions in the correct format.
It gets even more important when the user signs the transaction in an offline wallet, as the device by its nature cannot get access to the metadata without relying on the online wallet to provide it. This makes it so that the offline wallet needs to trust an online party, deeming the security assumptions of the offline devices, mute.
This RFC proposes a way for offline wallets to leverage metadata, within the constraints of these. The design idea is that the metadata is chunked and these chunks are put into a merkle tree. The root hash of this merkle tree represents the metadata. The offline wallets can use the root hash to decode transactions by getting proofs for the individual chunks of the metadata. This root hash is also included in the signed data of the transaction (but not sent as part of the transaction). The runtime is then including its known metadata root hash when verifying the transaction. If the metadata root hash known by the runtime differs from the one that the offline wallet used, it very likely means that the online wallet provided some fake data and the verification of the transaction fails.
Users depend on offline wallets to correctly display decoded transactions before signing. With merkleized metadata, they can be assured of the transaction's legitimacy, as incorrect transactions will be rejected by the runtime.
Polkadot's innovative design (both relay chain and parachains) present the ability to developers to upgrade their network as frequently as they need. These systems manage to have integrations working after the upgrades with the help of FRAME Metadata. This Metadata, which is in the order of half a MiB for most Polkadot-SDK chains, completely describes chain interfaces and properties. Securing this metadata is key for users to be able to interact with the Polkadot-SDK chain in the expected way.
On the other hand, offline wallets provide a secure way for Blockchain users to hold their own keys (some do a better job than others). These devices seldomly get upgraded, usually account for one particular network and hold very small internal memories. Currently in the Polkadot ecosystem there is no secure way of having these offline devices know the latest Metadata of the Polkadot-SDK chain they are interacting with. This results in a plethora of similar yet slightly different offline wallets for all different Polkadot-SDK chains, as well as the impediment of keeping these regularly updated, thus not fully leveraging Polkadot-SDK’s unique forkless upgrade feature.
The two main reasons why this is not possible today are:
This RFC proposes a solution to make FRAME Metadata compatible with offline signers in a secure way. As it leverages FRAME Metadata, it does not only ensure that offline devices can always keep up to date with every FRAME based chain, but also that every offline wallet will be compatible with all FRAME based chains, avoiding the need of per-chain implementations.
The idea for this RFC was brought up by runtime implementors and was extensively discussed with offline wallet implementors. It was designed in such a way that it can work easily with the existing offline wallet solutions in the Polkadot ecosystem.
The FRAME metadata provides a wide range of information about a FRAME based runtime. It contains information about the pallets, the calls per pallet, the storage entries per pallet, runtime APIs, and type information about most of the types that are used in the runtime. For decoding extrinsics on an offline wallet, what is mainly required is type information. Most of the other information in the FRAME metadata is actually not required for decoding extrinsics and thus it can be removed. Therefore, the following is a proposal on a custom representation of the metadata and how this custom metadata is chunked, ensuring that only the needed chunks required for decoding a particular extrinsic are sent to the offline wallet. The necessary information to transform the FRAME metadata type information into the type information presented in this RFC will be provided. However, not every single detail on how to convert from FRAME metadata into the RFC type information is described.
First, the MetadataDigest is introduced. After that, ExtrinsicMetadata is covered and finally the actual format of the type information. Then pruning of unrelated type information is covered and how to generate the TypeRefs. In the latest step, merkle tree calculation is explained.
MetadataDigest
ExtrinsicMetadata
TypeRef
V1
Option<[u8; 32]>
Some(metadata_hash)
The chunking may not be the optimal case for every kind of offline wallet.
All implementations are required to strictly follow the RFC to generate the metadata hash. This includes which hash function to use and how to construct the metadata types tree. So, all implementations are following the same security criteria. As the chains will calculate the metadata hash at compile time, the build process needs to be trusted. However, this is already a solved problem in the Polkadot ecosystem by using reproducible builds. So, anyone can rebuild a chain runtime to ensure that a proposal is actually containing the changes as advertised.
Implementations can also be tested easily against each other by taking some metadata and ensuring that they all come to the same metadata hash.
Privacy of users should also not be impacted. This assumes that wallets will generate the metadata hash locally and don't leak any information to third party services about which chunks a user will send to their offline wallet. Besides that, there is no leak of private information as getting the raw metadata from the chain is an operation that is done by almost everyone.
There should be no measurable impact on performance to Polkadot or any other chain using this feature. The metadata root hash is calculated at compile time and at runtime it is optionally used when checking the signature of a transaction. This means that at runtime no performance heavy operations are done.
The proposal alters the way a transaction is built, signed, and verified. So, this imposes some required changes to any kind of developer who wants to construct transactions for Polkadot or any chain using this feature. As the developer can pass 0 for disabling the verification of the metadata root hash, it can be easily ignored.
RFC 46 produced by the Alzymologist team is a previous work reference that goes in this direction as well.
On other ecosystems, there are other solutions to the problem of trusted signing. Cosmos for example has a standardized way of transforming a transaction into some textual representation and this textual representation is included in the signed data. Basically achieving the same as what the RFC proposes, but it requires that for every transaction applied in a block, every node in the network always has to generate this textual representation to ensure the transaction signature is valid.
This RFC proposes a change to the extrinsic format to incorporate a new transaction type, the "general" transaction.
"General" transactions, a new type of transaction that this RFC aims to support, are transactions which obey the runtime's extensions and have according extension data yet do not have hard-coded signatures. They are first described in Extrinsic Horizon and supported in 3685. They enable users to authorize origins in new, more flexible ways (e.g. ZK proofs, mutations over pre-authenticated origins). As of now, all transactions are limited to the account signing model for origin authorization and any additional origin changes happen in extrinsic logic, which cannot leverage the validation process of extensions.
An example of a use case for such an extension would be sponsoring the transaction fee for some other user. A new extension would be put in place to verify that a part of the initial payload was signed by the author under who the extrinsic should run and change the origin, but the payment for the whole transaction should be handled under a sponsor's account. A POC for this can be found in 3712.
The new "general" transaction type would coexist with both current transaction types for a while and, therefore, the current number of supported transaction types, capped at 2, is insufficient. A new extrinsic type must be introduced alongside the current signed and unsigned types. Currently, an encoded extrinsic's first byte indicate the type of extrinsic using the most significant bit - 0 for unsigned, 1 for signed - and the 7 following bits indicate the extrinsic format version, which has been equal to 4 for a long time.
By taking one bit from the extrinsic format version encoding, we can support 2 additional extrinsic types while also having a minimal impact on our capability to extend and change the extrinsic format in the future.
An extrinsic is currently encoded as one byte to identify the extrinsic type and version. This RFC aims to change the interpretation of this byte regarding the reserved bits for the extrinsic type and version. In the following explanation, bits represented using T make up the extrinsic type and bits represented using V make up the extrinsic version.
T
V
Currently, the bit allocation within the leading encoded byte is 0bTVVV_VVVV. In practice in the Polkadot ecosystem, the leading byte would be 0bT000_0100 as the version has been equal to 4 for a long time.
0bTVVV_VVVV
0bT000_0100
This RFC proposes for the bit allocation to change to 0bTTVV_VVVV. As a result, the extrinsic format version will be bumped to 5 and the extrinsic type bit representation would change as follows:
0bTTVV_VVVV
5
This change would reduce the maximum possible transaction version from the current 127 to 63. In order to bypass the new, lower limit, the extrinsic format would have to change again.
127
63
This change would allow Polkadot to support new types of transactions, with the specific "general" transaction type in mind at the time of writing this proposal.
The impact to developers and end-users is minimal as it would just be a bitmask update on their part for parsing the extrinsic type along with the version.
This change breaks backwards compatiblity because any transaction that is neither signed nor unsigned, but a new transaction type, would be interpreted as having a future extrinsic format version.
The original design was originally proposed in the TransactionExtension PR, which is also the motivation behind this effort.
Following this change, the "general" transaction type will be introduced as part of the Extrinsic Horizon effort, which will shape future work.
Extend the DHT authority discovery records with a signed creation time, so that nodes can determine which record is newer and always decide to prefer the newer records to the old ones.
Currently, we use the Kademlia DHT for storing records regarding the p2p address of an authority discovery key, the problem is that if the nodes decide to change its PeerId/Network key it will publish a new record, however because of the distributed and replicated nature of the DHT there is no way to tell which record is newer so both old PeerId and the new PeerId will live in the network until the old one expires(36h), that creates all sort of problem and leads to the node changing its address not being properly connected for up to 36h.
After this RFC, nodes are extended to decide to keep the new record and propagate the new record to nodes that have the old record stored, so in the end all the nodes will converge faster to the new record(in the order of minutes, not 36h)
Implementation of the rfc: https://github.com/paritytech/polkadot-sdk/pull/3786.
Current issue without this enhacement: https://github.com/paritytech/polkadot-sdk/issues/3673
Polkadot node developers.
This RFC heavily relies on the functionalities of the Kademlia DHT already in use by Polkadot. You can find a link to the specification here.
In a nutshell, on a specific node the current authority-discovery protocol publishes Kademila DHT records at startup and periodically. The records contain the full address of the node for each authorithy key it owns. The node tries also to find the full address of all authorities in the network by querying the DHT and picking up the first record it finds for each of the authority id it found on chain.
In theory the new protocol creates a bit more traffic on the DHT network, because it waits for DHT records to be received from more than one node, while in the current implementation we just take the first record that we receive and cancel all in-flight requests to other peers. However, because the redundancy factor will be relatively small and this operation happens rarerly, every 10min, this cost is negligible.
This RFC's implementation https://github.com/paritytech/polkadot-sdk/pull/3786 had been tested on various local test networks and versi.
With regard to security the creation time is wrapped inside SignedAuthorityRecord wo it will be signed with the authority id key, so there is no way for other malicious nodes to manipulate this field without the received node observing.
The changes are backwards compatible with the existing protocol, so nodes with both the old protocol and newer protocol can exist in the network, this is achieved by the fact that we use protobuf for serializing and deserializing the records, so new fields will be ignore when deserializing with the older protocol and vice-versa when deserializing an old record with the new protocol the new field will be None and the new code accepts this record as being valid.
The enhancements have been inspired by the algorithm specified in here
This RFC proposes a flexible unbonding mechanism for tokens that are locked from staking on the Relay Chain (DOT/KSM), aiming to enhance user convenience without compromising system security.
Locking tokens for staking ensures that Polkadot is able to slash tokens backing misbehaving validators. With changing the locking period, we still need to make sure that Polkadot can slash enough tokens to deter misbehaviour. This means that not all tokens can be unbonded immediately, however we can still allow some tokens to be unbonded quickly.
The new mechanism leads to a signficantly reduced unbonding time on average, by queuing up new unbonding requests and scaling their unbonding duration relative to the size of the queue. New requests are executed with a minimum of 2 days, when the queue is comparatively empty, to the conventional 28 days, if the sum of requests (in terms of stake) exceed some threshold. In scenarios between these two bounds, the unbonding duration scales proportionately. The new mechanism will never be worse than the current fixed 28 days.
In this document we also present an empirical analysis by retrospectively fitting the proposed mechanism to the historic unbonding timeline and show that the average unbonding duration would drastically reduce, while still being sensitive to large unbonding events. Additionally, we discuss implications for UI, UX, and conviction voting.
Note: Our proposition solely focuses on the locks imposed from staking. Other locks, such as governance, remain unchanged. Also, this mechanism should not be confused with the already existing feature of FastUnstake, which lets users unstake tokens immediately that have not received rewards for 28 days or longer.
As an initial step to gauge its effectiveness and stability, it is recommended to implement and test this model on Kusama before considering its integration into Polkadot, with appropriate adjustments to the parameters. In the following, however, we limit our discussion to Polkadot.
Polkadot has one of the longest unbonding periods among all Proof-of-Stake protocols, because security is the most important goal. Staking on Polkadot is still attractive compared to other protocols because of its above-average staking APY. However the long unbonding period harms usability and deters potential participants that want to contribute to the security of the network.
The current length of the unbonding period imposes significant costs for any entity that even wants to perform basic tasks such as a reorganization / consolidation of their stashes, or updating their private key infrastructure. It also limits participation of users that have a large preference for liquidity.
The combination of long unbonding periods and high returns has lead to the proliferation of liquid staking, where parachains or centralised exchanges offer users their staked tokens before the 28 days unbonding period is over either in original DOT/KSM form or derivative tokens. Liquid staking is harmless if few tokens are involved but it could result in many validators being selected by a few entities if a large fraction of DOTs were involved. This may lead to centralization (see here for more discussion on threats of liquid staking) and an opportunity for attacks.
The new mechanism greatly increases the competitiveness of Polkadot, while maintaining sufficient security.
Before diving into the details of how to implement the unbonding queue, we give readers context about why Polkadot has a 28-day unbonding period in the first place. The reason for it is to prevent long-range attacks (LRA) that becomes theoretically possible if more than 1/3 of validators collude. In essence, a LRA describes the inability of users, who disconnect from the consensus at time t0 and reconnects later, to realize that validators which were legitimate at a certain time, say t0 but dropped out in the meantime, are not to be trusted anymore. That means, for example, a user syncing the state could be fooled by trusting validators that fell outside the active set of validators after t0, and are building a competitive and malicious chain (fork).
LRAs of longer than 28 days are mitigated by the use of trusted checkpoints, which are assumed to be no more than 28 days old. A new node that syncs Polkadot will start at the checkpoint and look for proofs of finality of later blocks, signed by 2/3 of the validators. In an LRA fork, some of the validator sets may be different but only if 2/3 of some validator set in the last 28 days signed something incorrect.
If we detect an LRA of no more than 28 days with the current unbonding period, then we should be able to detect misbehaviour from over 1/3 of validators whose nominators are still bonded. The stake backing these validators is considerable fraction of the total stake (empirically it is 0.287 or so). If we allowed more than this stake to unbond, without checking who it was backing, then the LRA attack might be free of cost for an attacker. The proposed mechansim allows up to half this stake to unbond within 28 days. This halves the amount of tokens that can be slashed, but this is still very high in absolute terms. For example, at the time of writing (19.06.2024) this would translate to around 120 millions DOTs.
In addition to a simple queue, we could add a market component that lets users always unbond from staking at the minimum possible waiting time)(== LOWER_BOUND, e.g., 2 days), by paying a variable fee. To achieve this, it is reasonable to split the total unbonding capacity into two chunks, with the first capacity for the simple queue and the remaining capacity for the fee-based unbonding. By doing so, we allow users to choose whether they want the quickest unbond and paying a dynamic fee or join the simple queue. Setting a capacity restriction for both queues enables us to guarantee a predictable unbonding time in the simple queue, while allowing users with the respective willingness to pay to get out even earlier. The fees are dynamically adjusted and are proportional to the unbonding stake (and thereby expressed in a percentage of the requested unbonding stake). In contrast to a unified queue, this prevents the issue that users paying a fee jump in front of other users not paying a fee, pushing their unbonding time back (which would be bad for UX). The revenue generated could be burned.
LOWER_BOUND
This extension and further specifications are left out of this RFC, because it adds further complexity and the empirical analysis above suggests that average unbonding times will already be close the LOWER_BOUND, making a more complex design unnecessary. We advise to first implement the discussed mechanism and assess after some experience whether an extension is desirable.
UPPER_BOUND
NA
The authors cannot see any potential impact on performance.
The authors cannot see any potential impact on ergonomics for developers. We discussed potential impact on UX/UI for users above.
The authors cannot see any potential impact on compatibility. This should be assessed by the technical fellows.
This RFC proposes a change to the extrinsic format to include a transaction extension version.
The extrinsic format supports to be extended with transaction extensions. These transaction extensions are runtime specific and can be different per chain. Each transaction extension can add data to the extrinsic itself or extend the signed payload. This means that adding a transaction extension is breaking the chain specific extrinsic format. A recent example was the introduction of the CheckMetadatHash to Polkadot and all its system chains. As the extension was adding one byte to the extrinsic, it broke a lot of tooling. By introducing an extra version for the transaction extensions it will be possible to introduce changes to these transaction extensions while still being backwards compatible. Based on the version of the transaction extensions, each chain runtime could decode the extrinsic correctly and also create the correct signed payload.
CheckMetadatHash
RFC84 introduced the extrinsic format 5. The idea is to piggyback onto this change of the extrinsic format to add the extra version for the transaction extensions. If required, this could also come as extrinsic format 6, but 5 is not yet deployed anywhere.
6
The extrinsic format supports the following types of transactions:
The Version being a SCALE encoded u8 representing the version of the transaction extensions.
Version
In the chain runtime the version can be used to determine which set of transaction extensions should be used to decode and to validate the transaction.
This adds one byte more to each signed transaction.
This will ensure that changes to the transactions extensions can be done in a backwards compatible way.
Runtime developers need to take care of the versioning and ensure to bump as required, so that there are no compatibility breaking changes without a bump of the version. It will also add a little bit more code in the runtime to decode these old versions, but this should be neglectable.
When introduced together with extrinsic format version 5 from RFC84, it can be implemented in a backwards compatible way. So, transactions can still be send using the old extrinsic format and decoded by the runtime.
This RFC proposes a new instruction that provides a way to initiate on remote chains, asset transfers which transfer multiple types (teleports, local-reserve, destination-reserve) of assets, using XCM alone.
The currently existing instructions are too opinionated and force each XCM asset transfer to a single transfer type (teleport, local-reserve, destination-reserve). This results in inability to combine different types of transfers in single transfer which results in overall poor UX when trying to move assets across chains.
XCM is the de-facto cross-chain messaging protocol within the Polkadot ecosystem, and cross-chain assets transfers is one of its main use-cases. Unfortunately, in its current spec, it does not support initiating on a remote chain, one or more transfers that combine assets with different transfer types. @@ -6112,14 +10288,14 @@ For example, allows single XCM program execution to transfer multiple assets fro Kusama Asset Hub, over the bridge through Polkadot Asset Hub with final destination ParaP on Polkadot.
ParaP
With current XCM, we are limited to doing multiple independent transfers for each individual hop in order to move both "interesting" assets, but also "supporting" assets (used to pay fees).
A new instruction InitiateAssetsTransfer is introduced that initiates an assets transfer from the chain it is executed on, to another chain. The executed transfer is point-to-point (chain-to-chain) with all of the transfer properties specified in the instruction parameters. The instruction also @@ -6307,9 +10483,9 @@ by executing a single XCM message, even though we'll be mixing multiple ).unwrap(); }) }
InitiateAssetsTransfer
No drawbacks identified.
There should be no security risks related to the new instruction from the XCVM perspective. It follows the same pattern as with single-type asset transfers, only now it allows combining multiple types at once.
Improves security by enabling @@ -6318,16 +10494,16 @@ which minimizes the potential free/unpaid work that a receiving chain has to do. required execution fee payment, part of the instruction logic through the remote_fees: Option<AssetTransferFilter> parameter, which will make sure the remote XCM starts with a single-asset-holding-loading-instruction, immediately followed by a BuyExecution using said asset.
remote_fees: Option<AssetTransferFilter>
BuyExecution
This brings no impact to the rest of the XCM spec. It is a new, independent instruction, no changes to existing instructions.
Enhances the exposed functionality of Polkadot. Will allow multi-chain transfers that are currently forced to happen in multiple programs per asset per "hop", to be possible in a single XCM program.
No performance changes/implications.
The proposal enhances developers' and users' cross-chain asset transfer capabilities. This enhancement is optimized for XCM programs transferring multiple assets, needing to run their logic across multiple chains.
This enhancement is compatible with all existing XCM programs and versions.
The Transact XCM instruction currently forces the user to set a specific maximum weight allowed to the inner call and then also pay for that much weight regardless of how much the call actually needs in practice.
This RFC proposes improving the usability of Transact by removing that parameter and instead get and charge the actual weight of the inner call from its dispatch info on the remote chain.
The UX of using Transact is poor because of having to guess/estimate the require_weight_at_most weight used by the inner call on the target.
require_weight_at_most
We've seen multiple Transact on-chain failures caused by guessing wrong values for this require_weight_at_most even though the rest of the XCM program would have worked.
In practice, this parameter only adds UX overhead with no real practical value. Use cases fall in one of two categories:
We've had multiple OpenGov root/whitelisted_caller proposals initiated by core-devs completely or partially fail because of incorrect configuration of require_weight_at_most parameter. This is a strong indication that the instruction is hard to use.
root/whitelisted_caller
The proposed enhancement is simple: remove require_weight_at_most parameter from the instruction:
- Transact { origin_kind: OriginKind, require_weight_at_most: Weight, call: DoubleEncoded<Call> }, + Transact { origin_kind: OriginKind, call: DoubleEncoded<Call> },
The XCVM implementation shall no longer use require_weight_at_most for weighing. Instead, it shall weigh the Transact instruction by decoding and weighing the inner call.
call
No drawbacks, existing scenarios work as before, while this also allows new/easier flows.
Currently, an XCVM implementation can weigh a message just by looking at the decoded instructions without decoding the Transact's call, but assuming require_weight_at_most weight for it. With the new version it has to decode the inner call to know its actual weight.
But this does not actually change the security considerations, as can be seen below.
With the new Transact the weighing happens after decoding the inner call. The entirety of the XCM program containing this Transact needs to be either covered by enough bought weight using a BuyExecution, or the origin has to be allowed to do free execution.
The security considerations around how much can someone execute for free are the same for both this new version and the old. In both cases, an "attacker" can do the XCM decoding (including Transact inner calls) for free by adding a large enough BuyExecution without actually having the funds available.
In both cases, decoding is done for free, but in both cases execution fails early on BuyExecution.
No performance change.
Ergonomics are slightly improved by simplifying Transact API.
Compatible with previous XCM programs.
Elastic scaling is not resilient against griefing attacks without a way for a PoV (Proof of Validity) to commit to the particular core index it was intended for. This RFC proposes a way to include core index information in the candidate commitments and the CandidateDescriptor data structure in a backward compatible way. Additionally, it proposes the addition of a SessionIndex field in the CandidateDescriptor to make dispute resolution more secure and robust.
CandidateDescriptor
SessionIndex
This RFC proposes a way to solve two different problems:
This approach and alternatives have been considered and discussed in this issue.
The approach proposed below was chosen primarily because it minimizes the number of breaking changes, the complexity and takes less implementation and testing time. The proposal is to change the existing primitives while keeping binary compatibility with the older versions. We repurpose @@ -6640,28 +10816,28 @@ A candidate must not be backed if any of the following are true:
The only drawback is that further additions to the descriptor are limited to the amount of remaining unused space.
Standard testing (unit tests, CI zombienet tests) for functionality and mandatory security audit to ensure the implementation does not introduce any new security issues.
Backward compatibility of the implementation will be tested on testnets (Versi and Westend).
There is no impact on privacy.
Overall performance will be improved by not checking the collator signatures in runtime and nodes. The impact on the UMP queue and candidate receipt processing is negligible.
The ClaimQueueOffset along with the relay parent choice allows parachains to optimize their block production for either throughput or lower XCM message processing latency. A value of 0 with the newest relay parent provides the best latency while picking older relay parents avoids re-orgs.
ClaimQueueOffset
It is mandatory for elastic parachains to switch to the new receipt format and commit to a core by sending the UMPSignal::SelectCore message. It is optional but desired that all parachains switch to the new receipts for providing the session index for disputes.
UMPSignal::SelectCore
The implementation of this RFC itself must not introduce any breaking changes for the parachain runtime or collator nodes.
The proposed changes are not fully backward compatible, because older validators verify the collator signature of candidate descriptors.
Additional care must be taken before enabling the new descriptors by waiting for at least @@ -6686,12 +10862,12 @@ present in the receipt.
Any tooling that decodes UMP XCM messages needs an update to support or ignore the new UMP messages, but they should be fine to decode the regular XCM messages that come before the separator.
Forum discussion about a new CandidateReceipt format: https://forum.polkadot.network/t/pre-rfc-discussion-candidate-receipt-format-v2/3738
The implementation is extensible and future-proof to some extent. With minimal or no breaking changes, additional fields can be added in the candidate descriptor until the reserved space is exhausted
version
XCM already handles execution fees in an effective and efficient manner using the BuyExecution instruction. However, other types of fees are not handled as effectively -- for example, delivery fees. Fees exist that can't be measured using Weight -- as execution fees can -- so a new method should be thought up for those cases. @@ -6742,7 +10918,7 @@ This RFC proposes making the fee handling system simpler and more general, by do
Weight
fees
PayFees
Execution fees are handled correctly by XCM right now. However, the addition of extra fees, like for message delivery, result in awkward ways of integrating them into the XCVM implementation. This is because these types of fees are not included in the language. @@ -6750,14 +10926,14 @@ The standard should have a way to correctly deal with these implementation speci The new instruction moves the specified amount of fees from the holding register to a dedicated fees register that the XCVM can use in flexible ways depending on its implementation. The XCVM implementation is free to use these fees to pay for execution fees, transport fees, or any other type of fee that might be necessary. This moves the specifics of fees further away from the XCM standard, and more into the actual underlying XCVM implementation, which is a good thing.
The new instruction that will replace BuyExecution is a much simpler and general version: PayFees. This instruction takes one Asset, takes it from the holding register, and puts it into a new fees register. The XCVM implementation can now use this Asset to make sure every necessary fee is paid for, this includes execution fees, delivery fees, and any other type of fee @@ -6788,27 +10964,27 @@ BuyExecution { asset, weight_limit } PayFees { asset } // ...rest } -
Asset
There needs to be an explicit change from BuyExecution to PayFees, most often accompanied by a reduction in the assets passed in.
It might become a security concern if leftover fees are trapped, since a lot of them are expected.
There should be no performance downsides to this approach. The fees register is a simplification that may actually result in better performance, in the case an implementation is doing a workaround to achieve what this RFC proposes.
The interface is going to be very similar to the already existing one. Even simpler since PayFees will only receive one asset. That asset will allow users to limit the amount of fees they are willing to pay.
This RFC can't just change the semantics of the BuyExecution instruction since that instruction accepts any funds, uses what it needs and returns the rest immediately. The new proposed instruction, PayFees, doesn't return the leftover immediately, it keeps it in the fees register. In practice, the deprecated BuyExecution needs to be slowly rolled out in favour of PayFees.
The closed RFC PR on the xcm-format repository, before XCM RFCs got moved to fellowship RFCs: https://github.com/polkadot-fellows/xcm-format/pull/53.
This proposal would greatly benefit from an improved asset trapping system.
CustomAssetClaimer is also related, as it directly improves the ergonomics of this proposal.
LeftoverAssetsDestination execution hint would also similarly improve the ergonomics.
A previous XCM RFC (https://github.com/polkadot-fellows/xcm-format/pull/37) introduced a SetAssetClaimer instruction. This idea of instructing the XCVM to change some implementation-specific behavior is useful. In order to generalize this mechanism, this RFC introduces a new instruction SetHints and makes the SetAssetClaimer be just one of many possible execution hints.
SetAssetClaimer
SetHints
There is a need for specifying how certain implementation-specific things should behave. Things like who can claim the assets or what can be done instead of trapping assets. Another idea for a hint:
AssetForFees
LeftoverAssetsDestination
A new instruction, SetHints, will be added. This instruction will take a single parameter of type Hint, an enumeration. The first variant for this enum is AssetClaimer, which allows to specify a location that should be able to claim trapped assets. @@ -6884,27 +11060,27 @@ enum Hint { type NumVariants = /* Number of variants of the `Hint` enum */; } -
Hint
AssetClaimer
The SetHints instruction might be hard to benchmark, since we should look into the actual hints being set to know how much weight to attribute to it.
Hints are specified on a per-message basis, so they have to be specified at the beginning of a message. If they were to be specified at the end, hints like AssetClaimer would be useless if an error occurs beforehand and assets get trapped before ever reaching the hint.
The instruction takes a bounded vector of hints so as to not force barriers to allow an arbitrary number of SetHint instructions.
SetHint
The SetHints instruction provides a better integration with barriers. If we had to add one barrier for SetAssetClaimer and another for each new hint that's added, barriers would need to be changed all the time. Also, this instruction would make it simpler to write XCM programs. You only need to specify the hints you want in one single instruction at the top of your program.
The previous RFC PR in the xcm-format repository before XCM RFCs moved to fellowship RFCs: https://github.com/polkadot-fellows/xcm-format/pull/59.
This RFC aims to remove the NetworkIds of Westend and Rococo, arguing that testnets shouldn't go in the language.
NetworkId
Westend
Rococo
We've already seen the plans to phase out Rococo and Paseo has appeared. Instead of constantly changing the testnets included in the language, we should favor specifying them via their genesis hash, using NetworkId::ByGenesis.
NetworkId::ByGenesis
Remove Westend and Rococo from the included NetworkIds in the language.
This RFC will make it less convenient to specify a testnet, but not by a large amount.
It will very slightly reduce the ergonomics of testnet developers but improve the stability of the language.
NetworkId::Rococo and NetworkId::Westend can just use NetworkId::ByGenesis, as can other testnets.
NetworkId::Rococo
NetworkId::Westend
A previous attempt to add NetworkId::Paseo: https://github.com/polkadot-fellows/xcm-format/pull/58.
NetworkId::Paseo
XCM programs generated by the InitiateAssetTransfer instruction shall have the option to carry over the original origin all the way to the final destination. They shall do so by internally making use of AliasOrigin or ClearOrigin depending on given parameters.
InitiateAssetTransfer
AliasOrigin
ClearOrigin
This allows asset transfers to retain their original origin even across multiple hops.
Ecosystem chains would have to change their trusted aliasing rules to effectively make use of this feature.
Currently, all XCM asset transfer instructions ultimately clear the origin in the remote XCM message by use of the ClearOrigin instruction. This is done for security considerations to ensure that subsequent (user-controlled) instructions cannot command the authority of the sending chain.
The problem with this approach is that it limits what can be achieved on remote chains through XCM. Most XCM operations require having an origin, and following any asset transfer the origin is lost, meaning not much can be done other than depositing the transferred assets to some local account or transferring them onward to another chain.
For example, we cannot transfer some funds for buying execution, then do a Transact (all in the same XCM message).
Transact XCM programs today require a two step process:
And we want to be able to do it using a single XCM program.
In the case of XCM programs going from source-chain directly to dest-chain without an intermediary hop, we can enable scenarios such as above by using the AliasOrigin instruction instead of the ClearOrigin instruction.
source-chain
dest-chain
Instead of clearing the source-chain origin, the destination chain shall attempt to alias source-chain to "original origin" on the source chain. Most common such origin aliasing would be X1(Parachain(source-chain)) -> X2(Parachain(source-chain), AccountId32(origin-account)) for the case of a single hop transfer where the initiator is a (signed/pure/proxy) account origin-account on source-chain. @@ -7069,35 +11245,35 @@ involved chains.
X1(Parachain(source-chain))
X2(Parachain(source-chain), AccountId32(origin-account))
origin-account
In terms of ergonomics and user experience, this support for combining an asset transfer with a subsequent action (like Transact) is a net positive.
In terms of performance, and privacy, this is neutral with no changes.
In terms of security, the feature by itself is also neutral because it allows preserve_origin: false usage for operating with no extra trust assumptions. When wanting to support preserving origin, chains need to configure secure origin aliasing filters. The one suggested in this RFC should be the right choice for the majority of chains, but each chain will ultimately choose depending on their business model and logic (e.g. chain does not plan to integrate with Asset Hub). It is up to the individual chains to configure accordingly.
preserve_origin: false
Barriers should now allow AliasOrigin, DescendOrigin or ClearOrigin.
Normally, XCM program builders should audit their programs and eliminate assumptions of "no origin" on remote side of this instruction. In this case, the InitiateAssetsTransfer has not been released yet, it will be part of XCMv5, and we can make this change part of the same XCMv5 so that there isn't even the possibility of someone in the wild having built XCM programs using this instruction on those wrong assumptions.
The working assumption going forward is that the origin on the remote side can either be cleared or it can be the local origin's reanchored location. This assumption is in line with the current behavior of remote XCM programs sent over using pallet_xcm::send.
pallet_xcm::send
The existing DepositReserveAsset, InitiateReserveWithdraw and InitiateTeleport cross chain asset transfer instructions will not attempt to do origin aliasing and will always clear origin same as before for compatibility reasons.
DepositReserveAsset
InitiateReserveWithdraw
InitiateTeleport
No impact.
Improves ergonomics by allowing the local origin to operate on the remote chain even when the XCM program includes an asset transfer.
At the executor-level this change is backwards and forwards compatible. Both types of programs can be executed on new and old versions of XCM with no changes in behavior.
New version of the InitiateAssetsTransfer instruction acts same as before when used with preserve_origin: false.
For using the new capabilities, the XCM builder has to verify that the involved chains have the required origin-aliasing filters configured and use some new version of Barriers aware of AliasOrigin as an allowed alternative to ClearOrigin.
For compatibility reasons, this RFC proposes this mechanism be added as an enhancement to the yet unreleased InitiateAssetsTransfer instruction, thus eliminating possibilities of XCM logic breakages in the wild. Following the same logic, the existing DepositReserveAsset, InitiateReserveWithdraw and InitiateTeleport cross chain asset transfer instructions will not attempt to do origin aliasing and will always clear the origin same as before for compatibility reasons.
Any one of DepositReserveAsset, InitiateReserveWithdraw and InitiateTeleport instructions can be replaced with a InitiateAssetsTransfer instruction with or without origin aliasing, thus providing a clean and clear upgrade path for opting-in this new feature.
I AuthorsBastian Köcher -Summary +Summary The code of a runtime is stored in its own state, and when performing a runtime upgrade, this code is replaced. The new runtime can contain runtime migrations that adapt the state to the state layout as defined by the runtime code. This runtime migration is executed when building the first block with the new runtime code. Anything that interacts with the runtime state uses the state layout as defined by the runtime code. So, when trying to load something from the state in the block that applied the runtime upgrade, it will use the new state layout but will decode the data from the non-migrated state. In the worst case, the data is incorrectly decoded, which may lead to crashes or halting of the chain. This RFC proposes to store the new runtime code under a different storage key when applying a runtime upgrade. This way, all the off-chain logic can still load the old runtime code under the default storage key and decode the state correctly. The block producer is then required to use this new runtime code to build the next block. While building the next block, the runtime is executing the migrations and moves the new runtime code to the default runtime code location. So, the runtime code found under the default location is always the correct one to decode the state from which the runtime code was loaded. -Motivation +Motivation While the issue of having undecodable state only exists for the one block in which the runtime upgrade was applied, it still impacts anything that reads state data, like block explorers, UIs, nodes, etc. For block explorers, the issue mainly results in indexing invalid data and UIs may show invalid data to the user. For nodes, reading incorrect data may lead to a performance degradation of the network. There are also ways to prevent certain decoding issues from happening, but it requires that developers are aware of this issue and also requires introducing extra code, which could introduce further bugs down the line. So, this RFC tries to solve these issues by fixing the underlying problem of having temporary undecodable state. -Stakeholders +Stakeholders Relay chain/Parachain node developers Relay chain/Parachain node operators -Explanation +Explanation The runtime code is stored under the special key :code in the state. Nodes and other tooling read the runtime code under this storage key when they want to interact with the runtime for e.g., building/importing blocks or getting the metadata to read the state. To update the runtime code the runtime overwrites the value at :code, and then from the next block on, the new runtime will be loaded. This RFC proposes to first store the new runtime code under :pending_code in the state for one block. When the next block is being built, the block builder first needs to check if :pending_code is set, and if so, it needs to load the runtime from this storage key. While building the block the runtime will move :pending_code to :code to have the runtime code at the default location. Nodes importing the block will also need to load :pending_code if it exists to ensure that the correct runtime code is used. By doing it this way, the runtime code found at :code in the state of a block will always be able to decode the state. Furthermore, this RFC proposes to introduce system_version: 3. The system_version was introduced in RFC42. Version 3 would then enable the usage of :pending_code when applying a runtime code upgrade. This way, the feature can be introduced first and enabled later when the majority of the nodes have upgraded. -Drawbacks +Drawbacks Because the first block built with the new runtime code will move the runtime code from :pending_code to :code, the runtime code will need to be loaded. This means the runtime code will appear in the proof of validity of a parachain for the first block built with the new runtime code. Generally this is not a problem as the runtime code is also loaded by the parachain when setting the new runtime code. There is still the possibility of having state that is not migrated even when following the proposal as presented by this RFC. The issue is that if the amount of data to be migrated is too big, not all of it can be migrated in one block, because either it takes more time than there is assigned for a block or parachains for example have a fixed budget for their proof of validity. To solve this issue there already exist multi-block migrations that can chunk the migration across multiple blocks. Consensus-critical data needs to be migrated in the first block to ensure that block production etc., can continue. For the other data being migrated by multi-block migrations the migrations could for example expose to the outside which keys are being migrated and should not be indexed until the migration is finished. -Testing, Security, and Privacy +Testing, Security, and Privacy Testing should be straightforward and most of the existing testing should already be good enough. Extending with some checks that :pending_code is moved to :code. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance The performance should not be impacted besides requiring loading the runtime code in the first block being built with the new runtime code. -Ergonomics +Ergonomics It only alters the way blocks are produced and imported after applying a runtime upgrade. This means that only nodes need to be adapted to the changes of this RFC. -Compatibility +Compatibility The change will require that the nodes are upgraded before the runtime starts using this feature. Otherwise they will fail to import the block build by :pending_code. For Polkadot/Kusama this means that also the parachain nodes need to be running with a relay chain node version that supports this new feature. Otherwise the parachains will stop producing/finalizing nodes as they can not sync the relay chain any more. -Prior Art and References +Prior Art and References The issue initially reported a bug that led to this RFC. It also discusses multiple solutions for the problem. -Unresolved Questions +Unresolved Questions None -Future Directions and Related Material +Future Directions and Related Material Solve the issue of requiring loading the entire runtime code to move it into a different location by introducing a low-level move function. When using the V1 trie layout every value bigger than 32 bytes is put into the db separately. This means a low level move function would only need to move the hash of the runtime code from :code to :pending_code. @@ -7199,9 +11375,9 @@ For Polkadot/Kusama this means that also the parachain nodes need to be running AuthorsDaniel Shiposha -Summary +Summary This RFC proposes a metadata format for XCM-identifiable assets (i.e., for fungible/non-fungible collections and non-fungible tokens) and a set of instructions to communicate it across chains. -Motivation +Motivation Currently, there is no way to communicate metadata of an asset (or an asset instance) via XCM. The ability to query and modify the metadata is useful for two kinds of entities: @@ -7221,9 +11397,9 @@ For Polkadot/Kusama this means that also the parachain nodes need to be running Besides metadata modification, the ability to read it is also valuable. On-chain logic can interpret the NFT metadata, i.e., the metadata could have not only the media meaning but also a utility function within a consensus system. Currently, such a way of using NFT metadata is possible only within one consensus system. This RFC proposes making it possible between different systems via XCM so different chains can fetch and analyze the asset metadata from other chains. -Stakeholders +Stakeholders Runtime users, Runtime devs, Cross-chain dApps, Wallets. -Explanation +Explanation The Asset Metadata is information bound to an asset class (fungible or NFT collection) or an asset instance (an NFT). The Asset Metadata could be represented differently on different chains (or in other consensus entities). However, to communicate metadata between consensus entities via XCM, we need a general format so that any consensus entity can make sense of such information. @@ -7368,23 +11544,23 @@ The request can only be executed or rejected in its entirety. It must not be exe This RFC proposes to use the Undefined variant of a collection identified by an AssetId as a synonym of the collection itself. I.e., an asset Asset { id: <AssetId>, fun: NonFungible(AssetInstance::Undefined) } is considered an NFT representing the collection itself. As a singleton non-fungible instance is barely distinguishable from its collection, this convention shouldn't cause any problems. Thus, the AssetInstance docs must be updated accordingly in the implementations. -Drawbacks +Drawbacks Regarding ergonomics, no drawbacks were noticed. As for the user experience, it could discover new cross-chain use cases involving asset collections and NFTs, indicating a positive impact. There are no security concerns except for the ReportMetadata instruction, which implies that the source of the information must be trusted. In terms of performance and privacy, there will be no changes. -Testing, Security, and Privacy +Testing, Security, and Privacy The implementations must honor the contract for the new instructions. Namely, if the instance field has the value of AssetInstance::Undefined, the metadata must relate to the asset collection but not to a non-fungible token inside it. -Performance, Ergonomics, and Compatibility -Performance +Performance, Ergonomics, and Compatibility +Performance No significant impact. -Ergonomics +Ergonomics Introducing a standard metadata format and a way of communicating it is a valuable addition to the XCM format that potentially increases cross-chain interoperability without the need to form ad-hoc chain-to-chain integrations via Transact. -Compatibility +Compatibility This RFC proposes new functionality, so there are no compatibility issues. -Prior Art and References +Prior Art and References RFC: XCM Asset Metadata -Future Directions and Related Material +Future Directions and Related Material The original RFC draft contained additional metadata instructions. Though they could be useful, they're clearly outside the basic logic. So, this RFC version omits them to make the metadata discussion more focused on the core things. Nonetheless, there is hope that metadata approval instructions might be useful in the future, so they are mentioned here. You can read about the details in the original draft. (source) @@ -7429,9 +11605,9 @@ This RFC proposes to use the Undefined variant of a collection iden AuthorsBryan Chen, Jiyuan Zheng -Summary +Summary This proposal introduces PVQ (PolkaVM Query), a unified query interface that bridges different chain runtime implementations and client tools/UIs. PVQ provides an extension-based system where runtime developers can expose chain-specific functionality through standardized interfaces, while allowing client-side developers to perform custom computations on the data through PolkaVM programs. By abstracting away concrete implementations across chains and supporting both off-chain and cross-chain scenarios, PVQ aims to reduce code duplication and development complexity while maintaining flexibility for custom use cases. -Motivation +Motivation In Substrate, runtime APIs facilitate off-chain clients in reading the state of the consensus system. However, the APIs defined and implemented by individual chains often fall short of meeting the diverse requirements of client-side developers. For example, client-side developers may want some aggregated data from multiple pallets, or apply various custom transformations on the raw data. @@ -7466,12 +11642,12 @@ As a result, client-side developers frequently resort to directly accessing stor
The code of a runtime is stored in its own state, and when performing a runtime upgrade, this code is replaced. The new runtime can contain runtime migrations that adapt the state to the state layout as defined by the runtime code. This runtime migration is executed when building the first block with the new runtime code. Anything that interacts with the runtime state uses the state layout as defined by the runtime code. So, when trying to load something from the state in the block that applied the runtime upgrade, it will use the new state layout but will decode the data from the non-migrated state. In the worst case, the data is incorrectly decoded, which may lead to crashes or halting of the chain.
This RFC proposes to store the new runtime code under a different storage key when applying a runtime upgrade. This way, all the off-chain logic can still load the old runtime code under the default storage key and decode the state correctly. The block producer is then required to use this new runtime code to build the next block. While building the next block, the runtime is executing the migrations and moves the new runtime code to the default runtime code location. So, the runtime code found under the default location is always the correct one to decode the state from which the runtime code was loaded.
While the issue of having undecodable state only exists for the one block in which the runtime upgrade was applied, it still impacts anything that reads state data, like block explorers, UIs, nodes, etc. For block explorers, the issue mainly results in indexing invalid data and UIs may show invalid data to the user. For nodes, reading incorrect data may lead to a performance degradation of the network. There are also ways to prevent certain decoding issues from happening, but it requires that developers are aware of this issue and also requires introducing extra code, which could introduce further bugs down the line.
So, this RFC tries to solve these issues by fixing the underlying problem of having temporary undecodable state.
The runtime code is stored under the special key :code in the state. Nodes and other tooling read the runtime code under this storage key when they want to interact with the runtime for e.g., building/importing blocks or getting the metadata to read the state. To update the runtime code the runtime overwrites the value at :code, and then from the next block on, the new runtime will be loaded. This RFC proposes to first store the new runtime code under :pending_code in the state for one block. When the next block is being built, the block builder first needs to check if :pending_code is set, and if so, it needs to load the runtime from this storage key. While building the block the runtime will move :pending_code to :code to have the runtime code at the default location. Nodes importing the block will also need to load :pending_code if it exists to ensure that the correct runtime code is used. By doing it this way, the runtime code found at :code in the state of a block will always be able to decode the state. Furthermore, this RFC proposes to introduce system_version: 3. The system_version was introduced in RFC42. Version 3 would then enable the usage of :pending_code when applying a runtime code upgrade. This way, the feature can be introduced first and enabled later when the majority of the nodes have upgraded.
:code
:pending_code
system_version: 3
RFC42
3
Because the first block built with the new runtime code will move the runtime code from :pending_code to :code, the runtime code will need to be loaded. This means the runtime code will appear in the proof of validity of a parachain for the first block built with the new runtime code. Generally this is not a problem as the runtime code is also loaded by the parachain when setting the new runtime code. There is still the possibility of having state that is not migrated even when following the proposal as presented by this RFC. The issue is that if the amount of data to be migrated is too big, not all of it can be migrated in one block, because either it takes more time than there is assigned for a block or parachains for example have a fixed budget for their proof of validity. To solve this issue there already exist multi-block migrations that can chunk the migration across multiple blocks. Consensus-critical data needs to be migrated in the first block to ensure that block production etc., can continue. For the other data being migrated by multi-block migrations the migrations could for example expose to the outside which keys are being migrated and should not be indexed until the migration is finished.
Testing should be straightforward and most of the existing testing should already be good enough. Extending with some checks that :pending_code is moved to :code.
The performance should not be impacted besides requiring loading the runtime code in the first block being built with the new runtime code.
It only alters the way blocks are produced and imported after applying a runtime upgrade. This means that only nodes need to be adapted to the changes of this RFC.
The change will require that the nodes are upgraded before the runtime starts using this feature. Otherwise they will fail to import the block build by :pending_code. For Polkadot/Kusama this means that also the parachain nodes need to be running with a relay chain node version that supports this new feature. Otherwise the parachains will stop producing/finalizing nodes as they can not sync the relay chain any more.
The issue initially reported a bug that led to this RFC. It also discusses multiple solutions for the problem.
move
This RFC proposes a metadata format for XCM-identifiable assets (i.e., for fungible/non-fungible collections and non-fungible tokens) and a set of instructions to communicate it across chains.
Currently, there is no way to communicate metadata of an asset (or an asset instance) via XCM.
The ability to query and modify the metadata is useful for two kinds of entities:
Besides metadata modification, the ability to read it is also valuable. On-chain logic can interpret the NFT metadata, i.e., the metadata could have not only the media meaning but also a utility function within a consensus system. Currently, such a way of using NFT metadata is possible only within one consensus system. This RFC proposes making it possible between different systems via XCM so different chains can fetch and analyze the asset metadata from other chains.
Runtime users, Runtime devs, Cross-chain dApps, Wallets.
The Asset Metadata is information bound to an asset class (fungible or NFT collection) or an asset instance (an NFT). The Asset Metadata could be represented differently on different chains (or in other consensus entities). However, to communicate metadata between consensus entities via XCM, we need a general format so that any consensus entity can make sense of such information.
Undefined
AssetId
Asset { id: <AssetId>, fun: NonFungible(AssetInstance::Undefined) }
As a singleton non-fungible instance is barely distinguishable from its collection, this convention shouldn't cause any problems.
Thus, the AssetInstance docs must be updated accordingly in the implementations.
AssetInstance
Regarding ergonomics, no drawbacks were noticed.
As for the user experience, it could discover new cross-chain use cases involving asset collections and NFTs, indicating a positive impact.
There are no security concerns except for the ReportMetadata instruction, which implies that the source of the information must be trusted.
ReportMetadata
In terms of performance and privacy, there will be no changes.
The implementations must honor the contract for the new instructions. Namely, if the instance field has the value of AssetInstance::Undefined, the metadata must relate to the asset collection but not to a non-fungible token inside it.
instance
AssetInstance::Undefined
No significant impact.
Introducing a standard metadata format and a way of communicating it is a valuable addition to the XCM format that potentially increases cross-chain interoperability without the need to form ad-hoc chain-to-chain integrations via Transact.
This RFC proposes new functionality, so there are no compatibility issues.
RFC: XCM Asset Metadata
The original RFC draft contained additional metadata instructions. Though they could be useful, they're clearly outside the basic logic. So, this RFC version omits them to make the metadata discussion more focused on the core things. Nonetheless, there is hope that metadata approval instructions might be useful in the future, so they are mentioned here.
You can read about the details in the original draft.
This proposal introduces PVQ (PolkaVM Query), a unified query interface that bridges different chain runtime implementations and client tools/UIs. PVQ provides an extension-based system where runtime developers can expose chain-specific functionality through standardized interfaces, while allowing client-side developers to perform custom computations on the data through PolkaVM programs. By abstracting away concrete implementations across chains and supporting both off-chain and cross-chain scenarios, PVQ aims to reduce code duplication and development complexity while maintaining flexibility for custom use cases.
In Substrate, runtime APIs facilitate off-chain clients in reading the state of the consensus system. However, the APIs defined and implemented by individual chains often fall short of meeting the diverse requirements of client-side developers. For example, client-side developers may want some aggregated data from multiple pallets, or apply various custom transformations on the raw data. @@ -7466,12 +11642,12 @@ As a result, client-side developers frequently resort to directly accessing stor
The core idea of PVQ is to have a unified interface that meets the aforementioned requirements.
On the runtime side, an extension-based system is introduced to serve as a standardization layer across different chains. Each extension specification defines a set of cohesive APIs. @@ -7738,12 +11914,12 @@ enum PvqError {
ExceedsMaxMessageSize
Transport
As a newly introduced feature, PVQ operates independently and does not impact or degrade the performance of existing runtime implementations.
From the perspective of off-chain tooling, this proposal streamlines development by unifying multiple chain-specific RuntimeAPIs under a single consistent interface. This significantly benefits wallet and dApp developers by eliminating the need to handle individual implementations for similar operations across different chains. The proposal also enhances development flexibility by allowing custom computations to be modularly encapsulated as PolkaVM programs that interact with the exposed APIs.
For RuntimeAPI integration, the proposal defines new APIs, which do not break compatibility with existing interfaces. For XCM Integration, the proposal does not modify the existing XCM message format, which is backwards compatible.
There are several discussions related to the proposal, including:
Once PVQ and the aforementioned Facade Project are ready, there are opportunities to consolidate overlapping functionality between the two systems. For example, the metadata APIs could potentially be unified to provide a more cohesive interface for runtime information. This would help reduce duplication and improve maintainability while preserving the distinct benefits of each approach.
This RFC proposes a change that makes it possible to identify types of compressed blobs stored on-chain, as well as used off-chain, without the need for decompression.
Currently, a compressed blob does not give any idea of what's inside because the only thing that can be inside, according to the spec, is Wasm. In reality, other blob types are already being used, and more are to come. Apart from being error-prone by itself, the current approach does not allow to properly route the blob through the execution paths before its decompression, which will result in suboptimal implementations when more blob types are used. Thus, it is necessary to introduce a mechanism allowing to identify the blob type without decompressing it.
This proposal is intended to support future work enabling Polkadot to execute PolkaVM and, more generally, other-than-Wasm parachain runtimes, and allow developers to introduce arbitrary compression methods seamlessly in the future.
Node developers are the main stakeholders for this proposal. It also creates a foundation on which parachain runtime developers will build.
The current approach to compressing binary blobs involves using zstd compression, and the resulting compressed blob is prefixed with a unique 64-bit magic value specified in that subsection. The same procedure is used to compress both Wasm code blobs and proofs-of-validity. Currently, having solely a compressed blob, it's impossible to tell what's inside it without decompression, a Wasm blob, or a PoV. That doesn't cause problems in the current protocol, as Wasm blobs and PoV blobs take completely different execution paths in the code.
zstd
The changes proposed below are intended to define the means for distinguishing compressed blob types in a backward-compatible and future-proof way.
It is proposed to introduce an open list of 64-bit prefixes, each representing a compressed blob of a specific type compressed with a specific compression method. The currently used prefix becomes deprecated and will be removed or reused when it is no longer in use.
CBLOB_ZSTD_LEGACY
Currently, the only requirement for a compressed blob prefix is not to coincide with Wasm magic bytes (as stated in code comments). Changes proposed here increase prefix collision risk, given that arbitrary data may be compressed in the future. However, it must be taken into account that:
As the change increases granularity, it will positively affect both testing possibilities and security, allowing developers to check what's inside a given compressed blob precisely. Testing the change itself is trivial. Privacy is not affected by this change.
The current implementation's performance is not affected by this change. Future implementations allowing for the execution of other-than-Wasm parachain runtimes will benefit from this change performance-wise.
The end-user ergonomics is not affected. The ergonomics for developers will benefit from this change as it enables exact checks and less guessing.
The change is designed to be backward-compatible.
SDK PR#6704 (WIP) introduces a mechanism similar to that described in this proposal and proves the necessity of such a change.
This proposal creates a foundation for two future work directions:
This RFC proposes changes to the erasure coding algorithm and the method for computing the erasure root on Polkadot to improve performance of both processes.
The Data Availability (DA) Layer in Polkadot provides a foundation for shared security, enabling Approval Checkers and Collators to download Proofs-of-Validity (PoV) for security and liveness purposes respectively. @@ -7944,12 +12120,12 @@ The proposed change is orthogonal to RFC-47 and can be used in conjunction with collator nodes), we propose bundling another performance-enhancing breaking change that addresses the CPU bottleneck in the erasure coding process, but using a separate node feature (NodeFeatures part of HostConfiguration) for its activation.
NodeFeatures
HostConfiguration
We propose two specific changes:
Configuration::set_node_feature
Bundling this breaking change with RFC-47 might reset progress in updating collators. However, the omni node initiative should help mitigate this issue.
Testing is needed to ensure binary compatibility across implementations in multiple languages.
According to benchmarks:
This requires a breaking change that can be coordinated following the same approach as in RFC-47.
JAM already utilizes the same optimizations described in the Graypaper.
Future improvements could include:
This RFC proposes burning 80% of transaction fees accrued on Polkadot’s Relay Chain and, more significantly, on all its system parachains. The remaining 20% would continue to incentivize Validators (on the Relay Chain) and Collators (on system parachains) for including transactions. The 80:20 split is motivated by preserving the incentives for Validators, which are crucial for the security of the network, while establishing a consistent fee policy across the Relay Chain and all system parachains.
This proposal extends the system's deflationary direction and is enabling direct value capture for DOT holders of an overall increased activity on the network.
Historically, transaction fees on both the Relay Chain and the system parachains (with a few exceptions) have been relatively low. This is by design—Polkadot is built to scale and offer low-cost transactions. While this principle remains unchanged, growing network activity could still result in a meaningful accumulation of fees over time.
Implementing this RFC ensures that potentially increasing activity manifesting in more fees is captured for all token holders. It further aligns the way that the network is handling fees (such as from transactions or for coretime usage) is handled. The arguments in support of this are close to those outlined in RFC0010. Specifically, burning transaction fees has the following benefits:
By burning the transaction fees, the system effectively reduces the token supply and thereby increase the scarcity of the native token. This deflationary pressure can increase the token's long-term value and ensures that the value captured is translated equally to all existing token holders.
This proposal requires only minimal code changes, making it inexpensive to implement, yet it introduces a consistent policy for handling transaction fees across the network. Crucially, it positions Polkadot for a future where fee burning could serve as a counterweight to an otherwise inflationary token model, ensuring that value generated by network usage is returned to all DOT holders.
All DOT Token Holders: Benefit from reduced supply and direct value capture as network usage increases.
This RFC proposes an amendment to RFC-1 Agile Coretime: Renewal prices will no longer only be adjusted based on a configurable renewal bump, but also to the lower end of the current sale - if that turns out higher.
An implementation can be found here.
In RFC-1, we strived for perfect predictability on renewal prices, but what we expected unfortunately got proven in practice: Perfect predictability allows for core hoarding and cheap market manipulation, with the effect that both on @@ -8104,9 +12280,9 @@ extend to elastic scaling and in practice, even existing teams wanting to keep their core, because they forgot to renew in the interlude.
In a nutshell the current situation is severely hindering teams from deploying on Polkadot: We are essentially in a Denial of Service situation.
Stakeholders should be existing teams already having a core and new teams wanting to join the ecosystem.
This RFC proposes to fix this situation, by limiting renewal price predictability to reasonable levels, by introducing a weak coupling to the current market price: We ensure that the price for renewals is at least as high @@ -8174,13 +12350,13 @@ ensures that any additional attack will be expensive: 10 cores, results in to 100% capacity to have some leeway for governance in case of unforeseen attacks/weaknesses.
We are dropping almost perfect predictability on renewal prices, in favor of predictability within reasonable bounds. The introduction of a minimum price, will also result in huge relative price adjustments for existing tenants, because prices were so unreasonably low on Kusama. In practice this should not be an issue for any real project.
This RFC is proposing a single line of code change. A test has been added to make sure it is working as expected.
There are no privacy concerns.
The proposed changes are backwards compatible. No interfaces are changed. Performance is not affected. Ergonomics should be greatly improved especially for new entrants, as cores will be available for sale again. A configured minimum price also ensures that the starting price of the Dutch auction stays reasonably high, deterring sniping all the cores at the beginning of a sale.
This RFC is altering RFC-1 and taking ideas from RFC-17, mainly the introduction of a minimum price.
This RFC should solve the immediate problems we are seeing in production right now. Longer term, improvements to the market in terms of price discovery (RFC-17) should be considered, especially once demand grows.
Mitigation for this edge case is relatively simple: Bump renewals more aggressively the less cores are available on the free market. For now, leaving a few cores not for sale should be enough to mitigate such a situation.
(func $ext_storage_read_version_2 - (param $key i64) (param $value_out i64) (param $offset i32) (result i64)) -(func $ext_default_child_storage_read_version_2 - (param $child_storage_key i64) (param $key i64) (param $value_out i64) - (param $offset i32) (result i64)) -
The signature and behaviour of ext_storage_read_version_2 and ext_default_child_storage_read_version_2 is identical to their version 1 counterparts, but the return value has a different meaning. -The new functions directly return the number of bytes that were written in the value_out buffer. If the entry doesn't exist, a value of -1 is returned. Given that the host must never write more bytes than the size of the buffer in value_out, and that the size of this buffer is expressed as a 32 bits number, a 64bits value of -1 is not ambiguous.
(func $ext_storage_next_key_version_2 - (param $key i64) (param $out i64) (return i32)) -(func $ext_default_child_storage_next_key_version_2 - (param $child_storage_key i64) (param $key i64) (param $out i64) (return i32)) -
The behaviour of these functions is identical to their version 1 counterparts. -Instead of allocating a buffer, writing the next key to it, and returning a pointer to it, the new version of these functions accepts an out parameter containing a pointer-size to the memory location where the host writes the output. The runtime execution stops with an error if out is outside of the range of the memory of the virtual machine, even if the function wouldn't write anything to out. -These functions return the size, in bytes, of the next key, or 0 if there is no next key. If the size of the next key is larger than the buffer in out, the bytes of the key that fit the buffer are written to out and any extra byte that doesn't fit is discarded.
(func $ext_hashing_keccak_256_version_2 - (param $data i64) (param $out i32)) -(func $ext_hashing_keccak_512_version_2 - (param $data i64) (param $out i32)) -(func $ext_hashing_sha2_256_version_2 - (param $data i64) (param $out i32)) -(func $ext_hashing_blake2_128_version_2 - (param $data i64) (param $out i32)) -(func $ext_hashing_blake2_256_version_2 - (param $data i64) (param $out i32)) -(func $ext_hashing_twox_64_version_2 - (param $data i64) (param $out i32)) -(func $ext_hashing_twox_128_version_2 - (param $data i64) (param $out i32)) -(func $ext_hashing_twox_256_version_2 - (param $data i64) (param $out i32)) -(func $ext_trie_blake2_256_root_version_3 - (param $data i64) (param $version i32) (param $out i32)) -(func $ext_trie_blake2_256_ordered_root_version_3 - (param $data i64) (param $version i32) (param $out i32)) -(func $ext_trie_keccak_256_root_version_3 - (param $data i64) (param $version i32) (param $out i32)) -(func $ext_trie_keccak_256_ordered_root_version_3 - (param $data i64) (param $version i32) (param $out i32)) -(func $ext_default_child_storage_root_version_3 - (param $child_storage_key i64) (param $out i32)) -(func $ext_crypto_ed25519_generate_version_2 - (param $key_type_id i32) (param $seed i64) (param $out i32)) -(func $ext_crypto_sr25519_generate_version_2 - (param $key_type_id i32) (param $seed i64) (param $out i32) (return i32)) -(func $ext_crypto_ecdsa_generate_version_2 - (param $key_type_id i32) (param $seed i64) (param $out i32) (return i32)) -
(func $ext_default_child_storage_root_version_3 - (param $child_storage_key i64) (param $out i32)) -(func $ext_storage_root_version_3 - (param $out i32)) -
(func $ext_storage_clear_prefix_version_3 - (param $prefix i64) (param $limit i64) (param $removed_count_out i32) - (return i32)) -(func $ext_default_child_storage_clear_prefix_version_3 - (param $child_storage_key i64) (param $prefix i64) - (param $limit i64) (param $removed_count_out i32) (return i32)) -(func $ext_default_child_storage_kill_version_4 - (param $child_storage_key i64) (param $limit i64) - (param $removed_count_out i32) (return i32)) -
(func $ext_crypto_ed25519_sign_version_2 - (param $key_type_id i32) (param $key i32) (param $msg i64) (param $out i32) (return i32)) -(func $ext_crypto_sr25519_sign_version_2 - (param $key_type_id i32) (param $key i32) (param $msg i64) (param $out i32) (return i32)) -func $ext_crypto_ecdsa_sign_version_2 - (param $key_type_id i32) (param $key i32) (param $msg i64) (param $out i32) (return i32)) -(func $ext_crypto_ecdsa_sign_prehashed_version_2 - (param $key_type_id i32) (param $key i32) (param $msg i64) (param $out i32) (return i64)) -
(func $ext_crypto_secp256k1_ecdsa_recover_version_3 - (param $sig i32) (param $msg i32) (param $out i32) (return i64)) -(func $ext_crypto_secp256k1_ecdsa_recover_compressed_version_3 - (param $sig i32) (param $msg i32) (param $out i32) (return i64)) -
(func $ext_crypto_ed25519_num_public_keys_version_1 - (param $key_type_id i32) (return i32)) -(func $ext_crypto_ed25519_public_key_version_2 - (param $key_type_id i32) (param $key_index i32) (param $out i32)) -(func $ext_crypto_sr25519_num_public_keys_version_1 - (param $key_type_id i32) (return i32)) -(func $ext_crypto_sr25519_public_key_version_2 - (param $key_type_id i32) (param $key_index i32) (param $out i32)) -(func $ext_crypto_ecdsa_num_public_keys_version_1 - (param $key_type_id i32) (return i32)) -(func $ext_crypto_ecdsa_public_key_version_2 - (param $key_type_id i32) (param $key_index i32) (param $out i32)) -
Instead of calling ext_crypto_ed25519_public_key_version_1 in order to obtain the list of all keys at once, the runtime should instead call ext_crypto_ed25519_num_public_keys_version_1 in order to obtain the number of public keys available, then ext_crypto_ed25519_public_key_version_2 repeatedly. -The ext_crypto_ed25519_public_key_version_2 function writes the public key of the given key_index to the memory location designated by out. The key_index must be between 0 (included) and n (excluded), where n is the value returned by ext_crypto_ed25519_num_public_keys_version_1. Execution must trap if n is out of range.
(func $ext_offchain_http_request_start_version_2 - (param $method i64) (param $uri i64) (param $meta i64) (result i32)) -
(func $ext_offchain_http_request_write_body_version_2 - (param $method i64) (param $uri i64) (param $meta i64) (result i32)) -(func $ext_offchain_http_response_read_body_version_2 - (param $request_id i32) (param $buffer i64) (param $deadline i64) (result i64)) -
(func $ext_offchain_http_response_wait_version_2 - (param $ids i64) (param $deadline i64) (param $out i32)) -
(func $ext_offchain_http_response_header_name_version_1 - (param $request_id i32) (param $header_index i32) (param $out i64) (result i64)) -(func $ext_offchain_http_response_header_value_version_1 - (param $request_id i32) (param $header_index i32) (param $out i64) (result i64)) -
(func $ext_offchain_submit_transaction_version_2 - (param $data i64) (return i32)) -(func $ext_offchain_http_request_add_header_version_2 - (param $request_id i32) (param $name i64) (param $value i64) (result i32)) -
(func $ext_offchain_local_storage_read_version_1 - (param $kind i32) (param $key i64) (param $value_out i64) (param $offset i32) (result i64)) -
(func $ext_offchain_network_peer_id_version_1 - (param $out i64)) -
This function writes the PeerId of the local node to the memory location indicated by out. A PeerId is always 38 bytes long. -The runtime execution stops with an error if out is outside of the range of the memory of the virtual machine.
(func $ext_input_size_version_1 - (return i64)) -(func $ext_input_read_version_1 - (param $offset i64) (param $out i64)) -
The ext_input_read_version_1 host function copies some data from the input data to the memory of the runtime. The offset parameter indicates the offset within the input data where to start copying, and must be inferior or equal to the value returned by ext_input_size_version_1. The out parameter is a pointer-size containing the buffer where to write to. -The runtime execution stops with an error if offset is strictly superior to the size of the input data, or if out is outside of the range of the memory of the virtual machine, even if the amount of data to copy would be 0 bytes.
All the host functions that are being superceded by new host functions are now considered deprecated and should no longer be used. -The following other host functions are similarly also considered deprecated:
After this RFC, we can remove from the source code of the host the allocator altogether in a future version, by removing support for all the deprecated host functions. -This would remove the possibility to synchronize older blocks, which is probably controversial and requires a some preparations that are out of scope of this RFC.
P(n) = \begin{cases} - (P_{\text{old}} - P_{\text{min}}) \left(1 - \left(\frac{T - n}{T}\right)^d\right) + P_{\text{min}} & \text{if } n \leq T \\ - ((F - 1) \cdot P_{\text{old}} \cdot \left(\frac{n - T}{L - T}\right)^u) + P_{\text{old}} & \text{if } n > T -\end{cases} -
NEW_PRICE := IF CORES_SOLD <= BULK_TARGET THEN - (OLD_PRICE - MIN_PRICE) * (1 - ((BULK_TARGET - CORES_SOLD)^SCALE_DOWN / BULK_TARGET^SCALE_DOWN)) + MIN_PRICE -ELSE - ((MAX_PRICE_INCREASE_FACTOR - 1) * OLD_PRICE * ((CORES_SOLD - BULK_TARGET)^SCALE_UP / (BULK_LIMIT - BULK_TARGET)^SCALE_UP)) + OLD_PRICE -END IF -
BULK_TARGET = 30 -BULK_LIMIT = 45 -MIN_PRICE = 1 -MAX_PRICE_INCREASE_FACTOR = 2 -SCALE_DOWN = 2 -SCALE_UP = 2 -OLD_PRICE = 1000 -
BULK_TARGET = 30 -BULK_LIMIT = 45 -MIN_PRICE = 1 -MAX_PRICE_INCREASE_FACTOR = 3 -SCALE_DOWN = 2 -SCALE_UP = 1 -OLD_PRICE = 1000 -
BULK_TARGET = 30 -BULK_LIMIT = 45 -MIN_PRICE = 1 -MAX_PRICE_INCREASE_FACTOR = 1.5 -SCALE_DOWN = 0.5 -SCALE_UP = 2 -OLD_PRICE = 1000 -
BULK_TARGET = 30 -BULK_LIMIT = 45 -MIN_PRICE = 1 -MAX_PRICE_INCREASE_FACTOR = 1.5 -SCALE_DOWN = 1 -SCALE_UP = 1 -OLD_PRICE = 1000 -
#![allow(unused)] -fn main() { -// Relative location (from own perspective) -{ - parents: 0, - interior: Here -} - -// Relative location (from perspective of parent) -{ - parents: 0, - interior: [Parachain(1000)] -} - -// Relative location (from perspective of sibling) -{ - parents: 1, - interior: [Parachain(1000)] -} - -// Absolute location -[GlobalConsensus(Kusama), Parachain(1000)] -}
#![allow(unused)] -fn main() { -// Relative location (from own perspective) -// Not possible. - -// Relative location (from perspective of parent) -(b"ChildChain", Compact::<u32>::from(*index)).encode() - -// Relative location (from perspective of sibling) -(b"SiblingChain", Compact::<u32>::from(*index)).encode() - -}
#![allow(unused)] -fn main() { -( - b"GlobalConsensus", - network_id, - b"Parachain", - Compact::<u32>::from(para_id), - tail -).encode() -}
This RFC proposes a set of changes that will enable the new rent based approach to registering and storing validation code on-chain. -The new model, compared to the current one, will require periodic rent payments. The parachain won't be pruned automatically if the rent is not paid, but by permitting anyone to prune the parachain and rewarding the caller, there will be an incentive for the removal of the validation code.
#![allow(unused)] -fn main() { -trait Config { - // -- snip -- - - /// The deposit required for reserving a `ParaId`. - #[pallet::constant] - type ParaDeposit: Get<BalanceOf<Self>>; - - /// The deposit to be paid per byte stored on chain. - #[pallet::constant] - type DataDepositPerByte: Get<BalanceOf<Self>>; -} -}
#![allow(unused)] -fn main() { -trait Config { - // -- snip -- - - /// Defines how frequently the rent needs to be paid. - /// - /// The duration is set in sessions instead of block numbers. - #[pallet::constant] - type RentDuration: Get<SessionIndex>; - - /// The initial deposit amount for registering validation code. - /// - /// This is defined as a proportion of the deposit that would be required in the regular - /// model. - #[pallet::constant] - type RentalDepositProportion: Get<Perbill>; - - /// The recurring rental cost defined as a proportion of the initial rental registration deposit. - #[pallet::constant] - type RentalRecurringProportion: Get<Perbill>; -} -}
#![allow(unused)] -fn main() { -mod pallet { - // -- snip -- - - pub fn register_rental( - origin: OriginFor<T>, - id: ParaId, - genesis_head: HeadData, - validation_code: ValidationCode, - ) -> DispatchResult { /* ... */ } - - pub fn pay_rent(origin: OriginFor<T>, id: ParaId) -> DispatchResult { - /* ... */ - } -} -}
A call to register_rental will require the reservation of only a percentage of the deposit that would otherwise be required to register the validation code when using the regular model. -As described later in the Quick para re-registering section below, we will also store the code hash of each parachain to enable faster re-registration after a parachain has been pruned. For this reason the total initial deposit amount is increased to account for that.
#![allow(unused)] -fn main() { -// The logic for calculating the initial deposit for parachain registered with the -// new rent-based model: - -let validation_code_deposit = per_byte_fee.saturating_mul((validation_code.0.len() as u32).into()); - -let head_deposit = per_byte_fee.saturating_mul((genesis_head.0.len() as u32).into()) -let hash_deposit = per_byte_fee.saturating_mul(HASH_SIZE); - -let deposit = T::RentalDepositProportion::get().mul_ceil(validation_code_deposit) - .saturating_add(T::ParaDeposit::get()) - .saturating_add(head_deposit) - .saturating_add(hash_deposit) -}
#![allow(unused)] -fn main() { -/// Stores the validation code hash for parachains that successfully completed the -/// pre-checking process. -/// -/// This is stored to enable faster on-demand para re-registration in case its pvf has been earlier -/// registered and checked. -/// -/// NOTE: During a runtime upgrade where the pre-checking rules change this storage map should be -/// cleared appropriately. -#[pallet::storage] -pub(super) type CheckedCodeHash<T: Config> = - StorageMap<_, Twox64Concat, ParaId, ValidationCodeHash>; -}
As noted in this GitHub issue, we want to raise the per-byte cost of on-chain data storage. However, a substantial increase in this cost would make it highly impractical for on-demand parachains to register on Polkadot. -This RFC offers an alternative solution for on-demand parachains, ensuring that the per-byte cost increase doesn't overly burden the registration process.
In case of path A, there is one situation where the behaviour pre-RFC is not equivalent to the one post-RFC: when a host function that performs an allocation (for example ext_storage_get) is called, without this RFC this allocation might fail due to reaching the maximum heap pages, while after this RFC this will always succeed. -This is most likely not a problem, as storage values aren't supposed to be larger than a few megabytes at the very maximum.
In the unfortunate event where the runtime runs out of memory, path B would make it more difficult to relax the memory limit, as we would need to re-upload the entire Wasm, compared to updating only :heappages in path A or before this RFC. -In the case where the runtime runs out of memory only in the specific event where the Wasm runtime is modified, this could brick the chain. However, this situation is no different than the thousands of other ways that a bug in the runtime can brick a chain, and there's no reason to be particularily worried about this situation in particular.
This RFC would reduce the chance of a consensus issue between clients. -The :heappages are a rather obscure feature, and it is not clear what happens in some corner cases such as the value being too large (error? clamp?) or malformed. This RFC would completely erase these questions.
This RFC proposes adding a trivial governance track on Kusama to facilitate X (formerly known as Twitter) posts on the @kusamanetwork account. The technical aspect -of implementing this in the runtime is very inconsequential and straight-forward, though it might get more technical if the Fellowship wants to regulate this track -with a non-existent permission set. If this is implemented it would need to be followed up with:
The overall motivation for this RFC is to decentralize the management of the Kusama brand/communication channel to KSM holders. This is necessary in my opinion primarily -because of the inactivity of the account in recent history, with posts spanning weeks or months apart. I am currently unaware of who/what entity manages the Kusama -X account, but if they are affiliated with Parity or W3F this proposed solution could also offload some of the legal ramifications of making (or not making) -announcements to the public regarding Kusama. While centralized control of the X account would still be present, it could become totally moot if this RFC is implemented -and the community becomes totally autonomous in the management of Kusama's X posts.
This solution does not cover every single communication front for Kusama, but it does cover one of the largest. It also establishes a precedent for other communication channels -that could be offloaded to openGov, provided this proof-of-concept is successful.
Finally, this RFC is the epitome of experimentation that Kusama is ideal for. This proposal may spark newfound excitement for Kusama and help us realize Kusama's potential -for pushing boundaries and trying new unconventional ideas.
This idea has not been formalized by any individual (or group of) KSM holder(s). To my knowledge the socialization of this idea is contained -entirely in my recent X post here, but it is possible that an idea like this one has been discussed in -other places. It appears to me that the ecosystem would welcome a change like this which is why I am taking action to formalize the discussion.
First, we begin with this RFC to ensure all feedback can be discussed and implemented in the proposal. After the Fellowship and the community come to a reasonable -agreement on the changes necessary to make this happen, the Fellowship can merge changes into Kusama's runtime to include this new track with appropriate track configurations. -As a starting point, I recommend the following track configurations:
const APP_X_POST: Curve = Curve::make_linear(7, 28, percent(50), percent(100)); -const SUP_X_POST: Curve = Curve::make_reciprocal(?, ?, percent(?), percent(?), percent(?)); - -// I don't know how to configure the make_reciprocal variables to get what I imagine for support, -// but I recommend starting at 50% support and sharply decreasing such that 1% is sufficient quarterway -// through the decision period and hitting 0% at the end of the decision period, or something like that. - - ( - 69, - pallet_referenda::TrackInfo { - name: "x_post", - max_deciding: 50, - decision_deposit: 1 * UNIT, - prepare_period: 10 * MINUTES, - decision_period: 4 * DAYS, - confirm_period: 10 * MINUTES, - min_enactment_period: 1 * MINUTES, - min_approval: APP_X_POST, - min_support: SUP_X_POST, - }, - ), -
I also recommend restricting permissions of this track to only submitting remarks or batches of remarks - that's all we'll need for its purpose. I'm not sure how -easy that is to configure, but it is important since we don't want such an agile track to be able to make highly consequential calls.
It is important that we establish the specifications of referenda that will be submitted in this track to ensure that whatever automation tool is built can easily -make posts once a referendum is enacted. As stated above, we really only need a system.remark (or batch of remarks) to indicate the contents of a proposed X post. -The most straight-forward way to do this is to require remarks to adhere to X's requirements for making posts via their API.
For example, if I wanted to propose a post that contained the text "Hello World!" I would propose a referendum in the X post track that contains the following call data: -0x0000607b2274657874223a202248656c6c6f20576f726c6421227d (i.e. system.remark('{"text": "Hello World!"}')).
At first, we could support text posts only to prove the concept. Later on we could expand this spec to add support for media, likes, retweets, replies, polls, and -whatever other X features we want.
Once we agree on track configurations and specs for referenda in this track, the Fellowship can move forward with merging these changes into Kusama's runtime and -include them in its next release. We could also move forward with developing the necessary tools that would listen for enacted referenda to post automatically on X. -This would require coordination with whoever controls the X account; they would either need to run the tools themselves or add a third party as an authorized user to -run the tools to make posts on the account's behalf. This is a bottleneck for decentralization, but as long as the tools are run by the X account manager or by a trusted third party -it should be fine. I'm open to more decentralized solutions, but those always come at a cost of complexity.
For the tools themselves, we could open a bounty on Kusama for developers/teams to bid on. We could also just ask the community to step up with a Treasury proposal -to have anyone fund the build. Or, the Fellowship could make the release of these changes contingent on their endorsement of developers/teams to build these tools. Lots of options! -For the record, me and my team could develop all the necessary tools, but all because I'm proposing these changes doesn't entitle me to funds to build the tools needed -to implement them. Here's what would be needed:
The main drawback to this change is that it requires a lot of off-chain coordination. It's easy enough to include the track on Kusama but it's a totally different -challenge to make it function as intended. The tools need to be built and the auth tokens need to be managed. It would certainly add an administrative burden to whoever -manages the X account since they would either need to run the tools themselves or manage auth tokens.
This change also introduces on-going costs to the Treasury since it would need to compensate people to support the tools necessary to facilitate this idea. The ultimate -question is whether these on-going costs would be worth the ability for KSM holders to make posts on Kusama's X account.
There's also the risk of misconfiguring the track to make referenda too easy to pass, potentially allowing a malicious actor to get content posted on X that violates X's ToS. -If that happens, we risk getting Kusama banned on X!
This change might also be outside the scope of the Fellowship/openGov. Perhaps the best solution for the X account is to have the Treasury pay for a professional -agency to manage posts. It wouldn't be decentralized but it would probably be more effective in terms of creating good content.
Finally, this solution is merely pseudo-decentralization since the X account manager would still have ultimate control of the account. It's decentralized insofar as -the auth tokens are given to people actually running the tools; a house of cards is required to facilitate X posts via this track. Not ideal.
There's major precedent for configuring tracks on openGov given the amount of power tracks have, so it shouldn't be hard to come up with a sound configuration. -That's why I recommend restricting permissions of this track to remarks and batches of remarks, or something equally inconsequential.
If a track on Kusama promises users that compliant referenda enacted therein would be posted on Kusama's X account, users would expect that track to perform as promised. -If the house of cards tumbles down and a compliant referendum doesn't actually get anything posted, users might think that Kusama is broken or unreliable. This -could be damaging to Kusama's image and cause people to question the soundness of other features on Kusama.
As mentioned in the drawbacks, the performance of this feature would depend on off-chain coordinations. We can reduce the administrative burden of these coordinations -by funding third parties with the Treasury to deal with it, but then we're relying on trusting these parties.
By adding a new track to Kusama, governance platforms like Polkassembly or Nova Wallet would need to include it on their applications. This shouldn't be too -much of a burden or overhead since they've already built the infrastructure for other openGov tracks.
One reference to a similar feature requiring on-chain/off-chain coordination would be the Kappa-Sigma-Mu Society. Nothing on-chain necessarily enforces the rules -or facilitates bids, challenges, defenses, etc. However, the Society has managed to maintain itself with integrity to its rules. So I don't think this is totally -out of Kusama's scope. But it will require some off-chain effort to maintain.
Corporate Governance: -In a corporate setting, multisig accounts can be employed for decision-making processes. For example, a company may require the approval of multiple executives to initiate significant financial transactions.
Joint Accounts: -Multisig accounts can be used for joint accounts where multiple individuals need to authorize transactions. This is particularly useful in family finances or shared business accounts.
Decentralized Autonomous Organizations (DAOs): -DAOs can utilize multisig accounts to ensure that decisions are made collectively. Multiple key holders can be required to approve changes to the organization's rules or the allocation of funds.
#![allow(unused)] -fn main() { -enum CallOrHash<T: Config> { - Call(<T as Config>::RuntimeCall), - Hash(T::Hash), -} -}
#![allow(unused)] -fn main() { - /// Creates a new multisig account and attach signers with a threshold to it. - /// - /// The dispatch origin for this call must be _Signed_. It is expected to be a nomral AccountId and not a - /// Multisig AccountId. - /// - /// T::BaseCreationDeposit + T::PerSignerDeposit * signers.len() will be held from the caller's account. - /// - /// # Arguments - /// - /// - `signers`: Initial set of accounts to add to the multisig. These may be updated later via `add_signer` - /// and `remove_signer`. - /// - `threshold`: The threshold number of accounts required to approve an action. Must be greater than 0 and - /// less than or equal to the total number of signers. - /// - /// # Errors - /// - /// * `TooManySignatories` - The number of signatories exceeds the maximum allowed. - /// * `InvalidThreshold` - The threshold is greater than the total number of signers. - pub fn create_multisig( - origin: OriginFor<T>, - signers: BoundedBTreeSet<T::AccountId, T::MaxSignatories>, - threshold: u32, - ) -> DispatchResult -}
#![allow(unused)] -fn main() { - /// Starts a new proposal for a dispatchable call for a multisig account. - /// The caller must be one of the signers of the multisig account. - /// T::ProposalDeposit will be held from the caller's account. - /// - /// # Arguments - /// - /// * `multisig_account` - The multisig account ID. - /// * `call_or_hash` - The enum having the call or the hash of the call to be approved and executed later. - /// - /// # Errors - /// - /// * `MultisigNotFound` - The multisig account does not exist. - /// * `UnAuthorizedSigner` - The caller is not an signer of the multisig account. - /// * `TooManySignatories` - The number of signatories exceeds the maximum allowed. (shouldn't really happen as it's the first approval) - pub fn start_proposal( - origin: OriginFor<T>, - multisig_account: T::AccountId, - call_or_hash: CallOrHash, - ) -> DispatchResult -}
#![allow(unused)] -fn main() { - /// Approves a proposal for a dispatchable call for a multisig account. - /// The caller must be one of the signers of the multisig account. - /// - /// If a signer did approve -> reject -> approve, the proposal will be approved. - /// If a signer did approve -> reject, the proposal will be rejected. - /// - /// # Arguments - /// - /// * `multisig_account` - The multisig account ID. - /// * `call_or_hash` - The enum having the call or the hash of the call to be approved. - /// - /// # Errors - /// - /// * `MultisigNotFound` - The multisig account does not exist. - /// * `UnAuthorizedSigner` - The caller is not an signer of the multisig account. - /// * `TooManySignatories` - The number of signatories exceeds the maximum allowed. - /// This shouldn't really happen as it's an approval, not an addition of a new signer. - pub fn approve( - origin: OriginFor<T>, - multisig_account: T::AccountId, - call_or_hash: CallOrHash, - ) -> DispatchResult -}
#![allow(unused)] -fn main() { - /// Rejects a proposal for a multisig account. - /// The caller must be one of the signers of the multisig account. - /// - /// Between approving and rejecting, last call wins. - /// If a signer did approve -> reject -> approve, the proposal will be approved. - /// If a signer did approve -> reject, the proposal will be rejected. - /// - /// # Arguments - /// - /// * `multisig_account` - The multisig account ID. - /// * `call_or_hash` - The enum having the call or the hash of the call to be rejected. - /// - /// # Errors - /// - /// * `MultisigNotFound` - The multisig account does not exist. - /// * `UnAuthorizedSigner` - The caller is not an signer of the multisig account. - /// * `SignerNotFound` - The caller has not approved the proposal. - #[pallet::call_index(3)] - #[pallet::weight(Weight::default())] - pub fn reject( - origin: OriginFor<T>, - multisig_account: T::AccountId, - call_or_hash: CallOrHash, - ) -> DispatchResult -}
#![allow(unused)] -fn main() { - /// Executes a proposal for a dispatchable call for a multisig account. - /// Poropsal needs to be approved by enough signers (exceeds or equal multisig threshold) before it can be executed. - /// The caller must be one of the signers of the multisig account. - /// - /// This function does an extra check to make sure that all approvers still exist in the multisig account. - /// That is to make sure that the multisig account is not compromised by removing an signer during an active proposal. - /// - /// Once finished, the withheld deposit will be returned to the proposal creator. - /// - /// # Arguments - /// - /// * `multisig_account` - The multisig account ID. - /// * `call_or_hash` - We should have gotten the RuntimeCall (preimage) and stored it in the proposal by the time the extrinsic is called. - /// - /// # Errors - /// - /// * `MultisigNotFound` - The multisig account does not exist. - /// * `UnAuthorizedSigner` - The caller is not an signer of the multisig account. - /// * `NotEnoughApprovers` - approvers don't exceed the threshold. - /// * `ProposalNotFound` - The proposal does not exist. - /// * `CallPreImageNotFound` - The proposal doesn't have the preimage of the call in the state. - pub fn execute_proposal( - origin: OriginFor<T>, - multisig_account: T::AccountId, - call_or_hash: CallOrHash, - ) -> DispatchResult -}
#![allow(unused)] -fn main() { - /// Cancels an existing proposal for a multisig account. - /// Poropsal needs to be rejected by enough signers (exceeds or equal multisig threshold) before it can be executed. - /// The caller must be one of the signers of the multisig account. - /// - /// This function does an extra check to make sure that all rejectors still exist in the multisig account. - /// That is to make sure that the multisig account is not compromised by removing an signer during an active proposal. - /// - /// Once finished, the withheld deposit will be returned to the proposal creator./ - /// - /// # Arguments - /// - /// * `origin` - The origin multisig account who wants to cancel the proposal. - /// * `call_or_hash` - The call or hash of the call to be canceled. - /// - /// # Errors - /// - /// * `MultisigNotFound` - The multisig account does not exist. - /// * `ProposalNotFound` - The proposal does not exist. - pub fn cancel_proposal( - origin: OriginFor<T>, - multisig_account: T::AccountId, - call_or_hash: CallOrHash) -> DispatchResult -}
#![allow(unused)] -fn main() { - /// Cancels an existing proposal for a multisig account Only if the proposal doesn't have approvers other than - /// the proposer. - /// - /// This function needs to be called from a the proposer of the proposal as the origin. - /// - /// The withheld deposit will be returned to the proposal creator. - /// - /// # Arguments - /// - /// * `multisig_account` - The multisig account ID. - /// * `call_or_hash` - The hash of the call to be canceled. - /// - /// # Errors - /// - /// * `MultisigNotFound` - The multisig account does not exist. - /// * `ProposalNotFound` - The proposal does not exist. - pub fn cancel_own_proposal( - origin: OriginFor<T>, - multisig_account: T::AccountId, - call_or_hash: CallOrHash, - ) -> DispatchResult -}
#![allow(unused)] -fn main() { - /// Cleanup proposals of a multisig account. This function will iterate over a max limit per extrinsic to ensure - /// we don't have unbounded iteration over the proposals. - /// - /// The withheld deposit will be returned to the proposal creator. - /// - /// # Arguments - /// - /// * `multisig_account` - The multisig account ID. - /// - /// # Errors - /// - /// * `MultisigNotFound` - The multisig account does not exist. - /// * `ProposalNotFound` - The proposal does not exist. - pub fn cleanup_proposals( - origin: OriginFor<T>, - multisig_account: T::AccountId, - ) -> DispatchResult -}
#![allow(unused)] -fn main() { - /// Adds a new signer to the multisig account. - /// This function needs to be called from a Multisig account as the origin. - /// Otherwise it will fail with MultisigNotFound error. - /// - /// T::PerSignerDeposit will be held from the multisig account. - /// - /// # Arguments - /// - /// * `origin` - The origin multisig account who wants to add a new signer to the multisig account. - /// * `new_signer` - The AccountId of the new signer to be added. - /// * `new_threshold` - The new threshold for the multisig account after adding the new signer. - /// - /// # Errors - /// * `MultisigNotFound` - The multisig account does not exist. - /// * `InvalidThreshold` - The threshold is greater than the total number of signers or is zero. - /// * `TooManySignatories` - The number of signatories exceeds the maximum allowed. - pub fn add_signer( - origin: OriginFor<T>, - new_signer: T::AccountId, - new_threshold: u32, - ) -> DispatchResult -}
#![allow(unused)] -fn main() { - /// Removes an signer from the multisig account. - /// This function needs to be called from a Multisig account as the origin. - /// Otherwise it will fail with MultisigNotFound error. - /// If only one signer exists and is removed, the multisig account and any pending proposals for this account will be deleted from the state. - /// - /// # Arguments - /// - /// * `origin` - The origin multisig account who wants to remove an signer from the multisig account. - /// * `signer_to_remove` - The AccountId of the signer to be removed. - /// * `new_threshold` - The new threshold for the multisig account after removing the signer. Accepts zero if - /// the signer is the only one left.kkk - /// - /// # Errors - /// - /// This function can return the following errors: - /// - /// * `MultisigNotFound` - The multisig account does not exist. - /// * `InvalidThreshold` - The new threshold is greater than the total number of signers or is zero. - /// * `UnAuthorizedSigner` - The caller is not an signer of the multisig account. - pub fn remove_signer( - origin: OriginFor<T>, - signer_to_remove: T::AccountId, - new_threshold: u32, - ) -> DispatchResult -}
#![allow(unused)] -fn main() { - /// Sets a new threshold for a multisig account. - /// This function needs to be called from a Multisig account as the origin. - /// Otherwise it will fail with MultisigNotFound error. - /// - /// # Arguments - /// - /// * `origin` - The origin multisig account who wants to set the new threshold. - /// * `new_threshold` - The new threshold to be set. - /// # Errors - /// - /// * `MultisigNotFound` - The multisig account does not exist. - /// * `InvalidThreshold` - The new threshold is greater than the total number of signers or is zero. - set_threshold(origin: OriginFor<T>, new_threshold: u32) -> DispatchResult -}
#![allow(unused)] -fn main() { - /// Deletes a multisig account and all related proposals. - /// - /// This function needs to be called from a Multisig account as the origin. - /// Otherwise it will fail with MultisigNotFound error. - /// - /// # Arguments - /// - /// * `origin` - The origin multisig account who wants to cancel the proposal. - /// - /// # Errors - /// - /// * `MultisigNotFound` - The multisig account does not exist. - pub fn delete_account(origin: OriginFor<T>) -> DispatchResult -}
#![allow(unused)] -fn main() { -#[pallet::storage] - pub type MultisigAccount<T: Config> = StorageMap<_, Twox64Concat, T::AccountId, MultisigAccountDetails<T>>; - -/// The set of open multisig proposals. A proposal is uniquely identified by the multisig account and the call hash. -/// (maybe a nonce as well in the future) -#[pallet::storage] -pub type PendingProposals<T: Config> = StorageDoubleMap< - _, - Twox64Concat, - T::AccountId, // Multisig Account - Blake2_128Concat, - T::Hash, // Call Hash - MultisigProposal<T>, ->; -}
#![allow(unused)] -fn main() { -pub struct MultisigAccountDetails<T: Config> { - /// The signers of the multisig account. This is a BoundedBTreeSet to ensure faster operations (add, remove). - /// As well as lookups and faster set operations to ensure approvers is always a subset from signers. (e.g. in case of removal of an signer during an active proposal) - pub signers: BoundedBTreeSet<T::AccountId, T::MaxSignatories>, - /// The threshold of approvers required for the multisig account to be able to execute a call. - pub threshold: u32, - pub deposit: BalanceOf<T>, -} -}
#![allow(unused)] -fn main() { -pub struct MultisigProposal<T: Config> { - /// Proposal creator. - pub creator: T::AccountId, - pub creation_deposit: BalanceOf<T>, - /// The extrinsic when the multisig operation was opened. - pub when: Timepoint<BlockNumberFor<T>>, - /// The approvers achieved so far, including the depositor. - /// The approvers are stored in a BoundedBTreeSet to ensure faster lookup and operations (approve, reject). - /// It's also bounded to ensure that the size don't go over the required limit by the Runtime. - pub approvers: BoundedBTreeSet<T::AccountId, T::MaxSignatories>, - /// The rejectors for the proposal so far. - /// The rejectors are stored in a BoundedBTreeSet to ensure faster lookup and operations (approve, reject). - /// It's also bounded to ensure that the size don't go over the required limit by the Runtime. - pub rejectors: BoundedBTreeSet<T::AccountId, T::MaxSignatories>, - /// The block number until which this multisig operation is valid. None means no expiry. - pub expire_after: Option<BlockNumberFor<T>>, -} -}
Stateless Multisig: -Both as_multi and approve_as_multi has a similar parameters:
#![allow(unused)] -fn main() { -origin: OriginFor<T>, -threshold: u16, -other_signatories: Vec<T::AccountId>, -maybe_timepoint: Option<Timepoint<BlockNumberFor<T>>>, -call_hash: [u8; 32], -max_weight: Weight, -}
Stateful Multisig: -We have the following extrinsics:
#![allow(unused)] -fn main() { -pub fn start_proposal( - origin: OriginFor<T>, - multisig_account: T::AccountId, - call_or_hash: CallOrHash, - ) -}
#![allow(unused)] -fn main() { -pub fn approve( - origin: OriginFor<T>, - multisig_account: T::AccountId, - call_or_hash: CallOrHash, - ) -}
#![allow(unused)] -fn main() { -pub fn execute_proposal( - origin: OriginFor<T>, - multisig_account: T::AccountId, - call_or_hash: CallOrHash, - ) -}
Simplified table removing K from the equation: -| Pallet | Block Size | State Size | -|----------------|:-------------:|-----------:| -| Stateless | N^2 | Nil | -| Stateful | N | N |
createType(Call):: Call: failed decoding identity.setIdentity:: Struct: failed on args: {...}:: Struct: failed on pgpFingerprint: Option<[u8;20]>:: Expected input with 20 bytes (160 bits), found 40 bytes -
Change the upgrade process of a parachain runtime upgrade to become an off-chain -process with regards to the relay chain. Upgrades are still contained in -parachain blocks, but will no longer need to end up in relay chain blocks nor in -relay chain state.
Having parachain runtime upgrades go through the relay chain has always been -seen as a scalability concern. Due to optimizations in statement -distribution and asynchronous backing it became less crucial and got -de-prioritized, the original issue can be found -here.
With the introduction of Agile Coretime and in general our efforts to reduce -barrier to entry more for Polkadot more, the issue becomes more relevant again: -We would like to reduce the required storage deposit for PVF registration, with -the aim to not only make it cheaper to run a parachain (bulk + on-demand -coretime), but also reduce the amount of capital required for the deposit. With -this we would hope for far more parachains to get registered, thousands -potentially even ten thousands. With so many PVFs registered, updates are -expected to become more frequent and even attacks on service quality for other -parachains would become a higher risk.
We discussed introducing a separate signalling before submitting the actual -runtime, but I think we should just go one step further and make upgrades fully -off-chain. Which also helps bringing down deposit costs in a secure way, as we -are also actually reducing costs for the network.
As part of elastic scaling we are already planning to increase flexibility of UMP -messages, we can now use this to our advantage and introduce another UMP message:
#![allow(unused)] -fn main() { -enum UMPSignal { - // For elastic scaling - OnCore(CoreIndex), - // For off-chain upgrades - RequestCodeUpgrade(Hash), -} -}
We could also make that new message a regular XCM, calling an extrinsic on the -relay chain, but we will want to look into that message right after validation -on the backers on the node side, making a straight forward semantic message more -apt for the purpose.
We will introduce a new request/response protocol for both collators and -validators, with the following request/response:
#![allow(unused)] -fn main() { -struct RequestBlob { - blob_hash: Hash, -} - -struct BlobResponse { - blob: Vec<u8> -} -}
This protocol will be used by backers to request the PVF from collators in the -following conditions:
In case they received the collation via PoV distribution instead of from the -collator itself, they will use the exact same message to fetch from the valiator -they got the PoV from.
Once the candidate issuing RequestCodeUpgrade got backed on chain, validators -will start fetching the code from the backers as part of availability -distribution.
To mitigate attack vectors we should make sure that serving requests for code -can be treated as low priority requests. Thus I am suggesting the following -scheme:
Validators will notice via a runtime API (TODO: Define) that a new code has been requested, the -API will return the Hash and a counter, which starts at some configurable -value e.g. 10. The validators are now aware of the new hash and start fetching, -but they don't have to wait for the fetch to succeed to sign their bitfield.
Then on each further candidate from that chain that counter gets decremented. -Validators which have not yet succeeded fetching will now try again. This game -continues until the counter reached 0. Now it is mandatory to have to code in -order to sign a 1 in the bitfield.
PVF pre-checking will happen after the candidate which brought the counter to -0 has been successfully included and thus is also able to assume that 2/3 of -the validators have the code.
First when a candidate is backed we need to make the new hash available -(together with a counter) via a -runtime API so validators in availability distribution can check for it and -fetch it if changed (see previous section). For performance reasons, I think we -should not do an additional call, but replace the existing one with one containing the new additional information (Option<(Hash, Counter)>).
Once the candidate gets included (counter 0), the hash is given to pre-checking -and only after pre-checking succeeded (and a full session passed) it is finally -enacted and the parachain can switch to the new code. (Same process as it used -to be.)
If a backer receives a collation for a parachain it does not yet have the code -as enacted on chain (see "On-chain code upgrade process"), it will use above -request/response protocol to fetch it from whom it received the collation.
Validators in availability distribution will be changed to only sign a 1 in -the bitfield of a candidate if they not only have the chunk, but also the -currently active PVF. They will fetch it from backers in case they don't have it -yet.
We covered how validators get hold of new code, but when can they prune old ones? -In principle it is not an issue, if some validors prune code, because:
But the majority of validators should always keep the latest code of any -parachain and only prune the previous one, once the first candidate using the -new code got finalized. This ensures that disputes will always be able to -resolve.
The major drawback of this solution is the same as any solution the moves work -off-chain, it adds complexity to the node. E.g. nodes needing the PVF, need to -store them separately, together with their own pruning strategy as well.
Implementations adhering to this RFC, will respond to PVF requests with the -actual PVF, if they have it. Requesters will persist received PVFs on disk for -as long as they are replaced by a new one. Implementations must not be lazy -here, if validators only fetched the PVF when needed, they can be prevented from -participating in disputes.
Validators should treat incoming requests for PVFs in general with rather low -priority, but should prefer fetches from other validators over requests from -random peers.
Given that we are altering what set bits in the availability bitfields mean (not -only chunk, but also PVF available), it is important to have enough validators -upgraded, before we allow collators to make use of the new runtime upgrade -mechanism. Otherwise we would risk disputes to not being able to succeed.
This proposal lightens the load on the relay chain and is thus in general -beneficial for the performance of the network, this is achieved by the -following:
End users are only affected by better performance and more stable block times. -Parachains will need to implement the introduced request/response protocol and -adapt to the new signalling mechanism via an UMP message, instead of sending -the code upgrade directly.
For parachain operators we should emit events on initiated runtime upgrade and -each block reporting the current counter and how many blocks to go until the -upgrade gets passed to pre-checking. This is especially important for on-demand -chains or bulk users not occupying a full core. Further more that behaviour of -requiring multiple blocks to fully initiate a runtime upgrade needs to be well -documented.
We will continue to support the old mechanism for code upgrades for a while, but -will start to impose stricter limits over time, with the number of registered -parachains going up. With those limits in place parachains not migrating to the -new scheme might be having a harder time upgrading and will miss more blocks. I -guess we can be lenient for a while still, so the upgrade path for -parachains should be rather smooth.
Off-chain runtime upgrades have been discussed before, the architecture -described here is simpler though as it piggybacks on already existing features, -namely:
By no longer having code upgrade go through the relay chain, occupying a full relay -chain block, the impact on other parachains is already greatly reduced, if we -make distribution and PVF pre-checking low-priority processes on validators. The -only thing attackers might be able to do is delay upgrades of other parachains.
Which seems like a problem to be solved once we actually see it as a problem in -the wild (and can already be mitigated by adjusting the counter). The good thing -is that we have all the ingredients to go further if need be. Signalling no -longer actually includes the code, hence there is no need to reject the -candidate: The parachain can make progress even if we choose not to immediately -act on the request and no relay chain resources are wasted either.
We could for example introduce another UMP Signalling message -RequestCodeUpgradeWithPriority which not just requests a code upgrade, but -also offers some DOT to get ranked up in a queue.
Making this storage mechanism more general purpose is worth thinking about. E.g. -by resolving above "fee" question, we might also be able to resolve the pruning -question in a more generic way and thus could indeed open this storage facility -for other purposes as well. E.g. smart contracts, so the PoV would only need to -reference contracts by hash and the actual PoV is stored on validators and -collators and thus no longer needs to be part of the PoV.
#![allow(unused)] -fn main() { -enum BlobResponse { - Blob(Vec<u8>), - Blobs(MerkleTree), -} -}
With this the hash specified in the request can also be a merkle root and the -responder will respond with the entire merkle tree (only hashes, no payload). -Then the requester can traverse the leaf hashes and use the same request -response protocol to request any locally missing blobs in that tree.
One leaf would for example be the PVF others could be smart contracts. With a -properly specified format (e.g. which leaf is the PVF?), what we got here is -that a parachain can not only update its PVF, but additional data, -incrementally. E.g. adding another smart contract, does not require resubmitting -the entire PVF to validators, only the root hash on the relay chain gets -updated, then validators fetch the merkle tree and only fetch any missing -leaves. That additional data could be made available to the PVF via a to be -added host function. The nice thing about this approach is, that while we can -upgrade incrementally, lifetime is still tied to the PVF and we get all the same -guarantees. Assuming the validators store blobs by hash, we even get disk -sharing if multiple parachains use the same data (e.g. same smart contracts).
The SetFeesMode instruction and the fees_mode register allow for the existence of JIT withdrawal. -JIT withdrawal complicates the fee mechanism and leads to bugs and unexpected behaviour. -The proposal is to remove said functionality. -Another effort to simplify fee handling in XCM.
The JIT withdrawal mechanism creates bugs such as not being able to get fees when all assets are put into holding and none left in the origin location. -This is a confusing behavior, since there are funds for fees, just not where the XCVM wants them. -The XCVM should have only one entrypoint to fee payment, the holding register. -That way there is also less surface for bugs.
The SetFeesMode instruction will be removed. -The Fees Mode register will be removed.
Users will have to make sure to put enough assets in WithdrawAsset when -previously some things might have been charged directly from their accounts. -This leads to a more predictable behaviour though so it will only be -a drawback for the minority of users.
Implementations and benchmarking must change for most existing pallet calls -that send XCMs to other locations.
JIT withdrawal was a way of side-stepping the regular flow of XCM programs. -By removing it, the spec is simplified but now old use-cases have to work with -the original intended behaviour, which may result in more implementation work.
Existing programs in the ecosystem will break. -The instruction should be deprecated as soon as this RFC is approved -(but still fully supported), then removed in a subsequent XCM version -(probably deprecate in v5, remove in v6).
#![allow(unused)] -fn main() { -// Simplified version to illustrate the concept. -mod pallet_proxy_replica { - /// The part of the pure account preimage that has to be provided by a client. - struct Witness { - /// Pure proxy swapner - spawner: AccountId, - /// Disambiguation index - index: u16, - /// The block height and extrinsic index of when the pure account was created. - block_number: BlockNumber, - /// The extrinsic index. - ext_index: u32, - // Part of the preimage, but constant. - // proxy_type: ProxyType::Any, - } - // ... - - /// The replication call to be initiated on the source chain. - // Simplified version, the XCM part will be abstracted by the `Config` trait. - fn replicate(origin: SignedOrigin, witness: Witness, proxy: xcm::Location) -> ... { - let pure = ensure_signed(origin); - ensure!(pure == proxy_pallet::derive_pure_account(witness), Error::NotPureAccount); - let xcm = vec![ - DescendOrigin(who), - Transact( - // … - origin_kind: OriginKind::Xcm, - call: pallet_proxy_replica::create(witness, proxy).encode(), - ) - ]; - xcmTransport::send(xcm)?; - } - // … - - /// The call initiated by the source chain on the receiving chain. - // `Config::CreateOrigin` - generally open for whitelisted parachain IDs and - // converts `Origin::Xcm(ParachainA/AccountId32(pure1))` to `AccountID(pure1)`. - fn create(origin: Config::CreateOrigin, witness: Witness, proxy: xcm::Location) -> ... { - let pure = T::CreateOrigin::ensure_origin(origin); - ensure!(pure == proxy_pallet::derive_pure_account(witness), Error::NotPureAccount); - proxy_pallet::create_pure_proxy(pure, proxy); - } -} - -}
State syncing can require downloading several gigabytes of data, particularly for blockchains with large state sizes, such as Astar, which -has a state size exceeding 5 GiB (https://github.com/AstarNetwork/Astar/issues/1110). This presents a significant -challenge for nodes with slower network connections. Additionally, the current state sync implementation lacks a persistence feature (https://github.com/paritytech/polkadot-sdk/issues/4), -meaning any network disruption forces the node to re-download the entire state, making the process even more difficult.
“secp256r1” elliptic curve is a standardized curve by NIST which has the same calculations by different input parameters with “secp256k1” elliptic curve. The cost of combined attacks and the security conditions are almost the same for both curves. Adding a host function can provide signature verifications using the “secp256r1” elliptic curve in the runtime and multi-faceted benefits can occur. One important factor is that this curve is widely used and supported in many modern devices such as Apple’s Secure Enclave, Webauthn, Android Keychain which proves the user adoption. Additionally, the introduction of this host function could enable valuable features in the account abstraction which allows more efficient and flexible management of accounts by transaction signs in mobile devices. -Most of the modern devices and applications rely on the “secp256r1” elliptic curve. The addition of this host function enables a more efficient verification of device native transaction signing mechanisms. For example:
#![allow(unused)] -fn main() { -fn ext_secp256r1_ecdsa_verify_prehashed_version_1( - sig: &[u8; 64], - msg: &[u8; 32], - pub_key: &[u8; 64], -) -> bool; -}
A followup of the RFC-0014. This RFC proposes adding a new collective to the Polkadot Collectives -Chain: The Unbrick Collective, as well as improvements in the mechanisms that will allow teams -operating paras that had stopped producing blocks to be assisted, in order to restore the production -of blocks of these paras.
Since the initial launch of Polkadot parachains, there has been many incidients causing parachains -to stop producing new blocks (therefore, being bricked) and many occurrences that required -Polkadot governance to update the parachain head state/wasm. This can be due to many reasons range -from incorrectly registering the initial head state, inability to use sudo key, bad runtime -migration, bad weight configuration, and bugs in the development of the Polkadot SDK.
Currently, when the para is not unlocked in the paras registrar1, the Root origin is required to -perform such actions, involving the governance process to invoke this origin, which can be very -resource expensive for the teams. The long voting and enactment times also could result significant -damage to the parachain and users.
Finally, other instances of governance that might enact a call using the Root origin (like the -Polkadot Fellowship), due to the nature of their mission, are not fit to carry these kind of tasks.
In consequence, the idea of a Unbrick Collective that can provide assistance to para teams when -they brick and further protection against future halts is reasonable enough.
The Unbrick Collective is defined as an unranked collective of members, not paid by the Polkadot -Treasury. Its main goal is to serve as a point of contact and assistance for enacting the actions -needed to unbrick a para. Such actions are:
In order to ensure these changes are safe enough for the network, actions enacted by the Unbrick -Collective must be whitelisted via similar mechanisms followed by collectives like the Polkadot -Fellowship. This will prevent unintended, not overseen changes on other paras to occur.
Also, teams might opt-in to delegate handling their para in the registry to the Collective. This -allows to perform similar actions using the paras registrar, allowing for a shorter path to unbrick a -para.
Initially, the unbrick collective has powers similar to a parachains own sudo, but permits more -decentralized control. In the future, Polkadot shall provide functionality like SPREE or JAM that -exceeds sudo permissions, so the unbrick collective cannot modify those state roots or code.
flowchart TD - A[Start] - - A -- Bricked --> C[Request para unlock via Root] - C -- Approved --> Y - C -- Rejected --> A - - D[unbrick call proposal on WhitelistedUnbrickCaller] - E[whitelist call proposal on the Unbrick governance] - E -- call whitelisted --> F[unbrick call enacted] - D -- unbrick called --> F - F --> Y - - A -- Not bricked --> O[Opt-in to the Collective] - O -- Bricked --> D - O -- Bricked --> E - - Y[update PVF / head state] -- Unbricked --> Z[End] -
Initially, a para team has two paths to handle a potential unbrick of their para in the case it -stops producing blocks.
The collective will be initially created without members (no seeding). There will be additional -governance proposals to setup the seed members.
The members are responsible to verify the technical details of the unbrick requests (i.e. the hash -of the new PVF being set). Therefore, they must have the technical capacity to perform such tasks.
The ability to modify the Head State and/or the PVF of a para means a possibility to perform -arbitrary modifications of it (i.e. take control the native parachain token or any bridged assets -in the para).
This could introduce a new attack vector, and therefore, such great power needs to be handled -carefully.
This RFC should improve the experience for new and existing parachain teams, lowering the barrier -to unbrick a stalled para.
The paras registrar refers to a pallet in the Relay, responsible to gather registration info -of the paras, the locked/unlocked state, and the manager info.
In an attempt to mitigate risks derived from unwanted behaviours around long decision periods on -referenda, this proposal describes how to finalize and decide a result of a poll via a -mechanism similar to candle auctions.
Referenda protocol provide permissionless and efficient mechanisms to enable governance actors to -decide the future of the blockchains around Polkadot network. However, they pose a series of risks -derived from the game theory perspective around these mechanisms. One of them being where an actor -uses the the public nature of the tally of a poll as a way of determining the best point in time to -alter a poll in a meaningful way.
While this behaviour is expected based on the current design of the referenda logic, given the -recent extension of ongoing times (up to 1 month), the incentives for a bad actor to cause losses -on a proposer, reflected as wasted cost of opportunity increase, and thus, this otherwise -reasonable outcome becomes an attack vector, a potential risk to mitigate, especially when such -attack can compromise critical guarantees of the protocol (such as its upgradeability).
To mitigate this, the referenda underlying mechanisms should incentive actors to cast their votes -on a poll as early as possible. This proposal's approach suggests using a Candle Auction that will -be determined right after the confirm period finishes, thus decreasing the chances of actors to -alter the results of a poll on confirming state, and instead incentivizing them to cast their votes -earlier, on deciding state.
Currently, the process of a referendum/poll is defined as an sequence between an ongoing state -(where accounts can vote), comprised by a with a preparation period, a decision period, and a -confirm period. If the poll is passing before the decision period ends, it's possible to push -forward to confirm period, and still, go back in case the poll fails. Once the decision period -ends, a failure of the poll in the confirm period will lead to the poll to ultimately be rejected.
stateDiagram-v2 - sb: Submission - pp: Preparation Period - dp: Decision Period - cp: Confirmation Period - state dpd <<choice>> - state ps <<choice>> - cf: Approved - rj: Rejected - - [*] --> sb - sb --> pp - pp --> dp: decision period starts - dp --> cp: poll is passing - dp --> ps: decision period ends - ps --> cp: poll is passing - cp --> dpd: poll fails - dpd --> dp: decision period not deadlined - ps --> rj: poll is failing - dpd --> rj: decision period deadlined - cp --> cf - cf --> [*] - rj --> [*] -
This mechanism MUST be enabled via a configuration parameter. Once enabled, the referenda system -MAY record the next poll ID from which to start enabling this mechanism. This is to preserve -backwards compatibility with currently ongoing polls.
A record of the poll status (whether it is passing or not) is stored once the decision period is -finished.
Including a Finalization period as part of the ongoing state. From this point, the poll MUST -be immutable at this point.
This period begins the moment after confirm period ends, and extends the decision for a couple -of blocks, until the VRF seed used to determine the candle block can be considered -"good enough". This is, not known before the ongoing period (decision/confirmation) was over.
Once that happens, a random block within the confirm period is chosen, and the decision of -approving or rejecting the poll is based on the status immediately before the block where the -candle was "lit-off".
stateDiagram-v2 - sb: Submission - pp: Preparation Period - dp: Decision Period - cp: Confirmation Period - cds: Finalization - state dpd <<choice>> - state ps <<choice>> - state cd <<choice>> - cf: Approved - rj: Rejected - - [*] --> sb - sb --> pp - pp --> dp: decision period starts - dp --> cp: poll is passing - ps --> cp: poll is passing - dp --> ps: decision period ends - ps --> rj: poll is failing - cp --> dpd: poll fails - dpd --> cp: decision period over - dpd --> dp: decision period not over - cp --> cds: confirmation period ends - cds --> cd: define moment when candle lit-off - cd --> cf: poll passed - cd --> rj: poll failed - cf --> [*] - rj --> [*] -
This approach doesn't include a mechanism to determine whether a change of the poll status in the -confirming period is due to a legitimate change of mind of the voters, or an exploitation of its -aforementioned vulnerabilities (like a sniping attack), instead treating all of them as potential -attacks.
This is an issue that can be addressed by additional mechanisms, and heuristics that can help -determine the probability of a change of poll status to happen as a result of a legitimate behaviour.
The implementation of this RFC will be tested on testnets (Paseo and Westend) first. Furthermore, it -should be enabled in a canary network (like Kusama) to ensure the behaviours it is trying to address -is indeed avoided.
The added steps imply pessimization, necessary to meet the expected changes. An implementation MUST -exit from the Finalization period as early as possible to minimize this impact.
This proposal does not alter the already exposed interfaces or developers or end users. However, they -must be aware of the changes in the additional overhead the new period might incur (these depend on the -implemented VRF).
This proposal does not break compatibility with existing interfaces, older versions, but it alters the -previous implementation of the referendum processing algorithm.
An acceptable upgrade strategy that can be applied is defining a point in time (block number, poll index) -from which to start applying the new mechanism, thus, not affecting the already ongoing referenda.
This RFC proposes the definition of version 5 extrinsics along with changes to the specification and -encoding from version 4.
RFC84 -introduced the specification of General transactions, a new type of extrinsic besides the Signed -and Unsigned variants available previously in version 4. Additionally, -RFC99 -introduced versioning of transaction extensions through an extra byte in the extrinsic encoding. -Both of these changes require an extrinsic format version bump as both the semantics around -extensions as well as the actual encoding of extrinsics need to change to accommodate these new -features.
The introduction of General transactions allows the authorization of any and all origins through -extensions. This means that, with the appropriate extension, General transactions can replicate -the same behavior present-day v4 Signed transactions. Specifically for Polkadot chains, an example -implementation for such an extension is -VerifySignature, -introduced in the Transaction Extension -PR3685. Other extensions can be inserted -into the extension pipeline to authorize different custom origins. Therefore, a Signed extrinsic -variant is redundant to a General one strictly in terms of user functionality and could eventually -be deprecated and removed.
As with version 4, the encoded extrinsic v5 is a SCALE encoded vector of bytes (u8), therefore -starting with the encoded length of the following bytes in compact format. The leading byte after -the length determines the version and type of extrinsic, as specified by -RFC84. -For reasons mentioned above, this RFC removes the Signed variant for v5 extrinsics.
For General transactions, as stated in -RFC99, -an extension version byte must be added to the extrinsic format. This byte should allow runtimes to -expose more than one set of extensions which can be used for a transaction. As far as the v5 -extrinsic encoding is concerned, this extension byte should be encoded immediately after the leading -encoding byte. The extension version byte should be included in payloads to be signed by all -extensions configured by runtime devs to ensure a user's extension version choice cannot be altered -by third parties.
In order to run a transaction with a signed origin in extrinsic version 5, a user must create the -transaction with an instance of at least one extension responsible for authorizing Signed origins -with a provided signature.
As stated before, PR3685 comes with a -Transaction Extension which replicates the current Signed transactions in v5 extrinsics, namely -VerifySignature. -I will use this extension as an example on how to replicate current Signed transaction -functionality in the new v5 extrinsic format, though the runtime logic is not constrained to this -particular implementation.
This extension leverages the new inherited implication functionality introduced in -TransactionExtension and creates a payload to be signed using the data of all extensions after -itself in the extension pipeline. This extension can be configured to accept a MultiSignature, -which makes it compatible with all signature types currently used in Polkadot.
In the context of using an extension such as VerifySignature, for example, to replicate current -Signed transaction functionality, the steps to generate the payload to be signed would be:
#![allow(unused)] -fn main() { -// Step 1: encode the bytes -let encoded = (extension_version_byte, call, transaction_extension, transaction_extension_implicit).encode(); -// Step 2: hash them -let payload = blake2_256(&encoded[..]); -// Step 3: sign the payload -let signature = keyring.sign(&payload[..]); -}
In order to minimize the number of changes to the extrinsic format version and also to help all -consumers downstream in the transition period between these extrinsic versions, we should:
The metadata will have to accommodate two distinct extrinsic format versions at a given point in -time in order to provide the new functionality in a non-breaking way for users and tooling.
Although having to support multiple extrinsic versions in metadata involves extra work, the change -is ultimately an improvement to metadata and the extra functionality may be useful in other future -scenarios.
This change makes the authorization through signatures configurable by runtime devs in version 5 -extrinsics, as opposed to version 4 where the signing payload algorithm and signatures were -hardcoded. This moves the responsibility of ensuring proper authentication through -TransactionExtension to the runtime devs, but a sensible default which closely resembles the -present day behavior will be provided in VerifySignature.
Tooling will have to adapt to be able to tell which authorization scheme is used by a particular -transaction by decoding the extension and checking which particular TransactionExtension in the -pipeline is enabled to do the origin authorization. Previously, this was done by simply checking -whether the transaction is signed or unsigned, as there was only one method of authentication.
As long as extrinsic version 4 is still exposed in the metadata when version 5 will be introduced, -the changes will not break existing infrastructure. This should give enough time for tooling to -support version 5 and to remove version 4 in the future.
This is a result of the work in Extrinsic -Horizon and -RFC99.
Following this change, extrinsic version 5 will be introduced as part of the Extrinsic -Horizon effort, which will shape future -work.
The current election mechanism for permissionless collators on system chains was introduced in -RFC-7. -This RFC proposes a mechanism to facilitate replacements in the invulnerable sets of system chains -by breaking down barriers that exist today.
Following RFC-7 and the introduction of the collator election -mechanism, anyone can now collate on a system -chain on the permissionless slots, but the invulnerable set has been a contentious issue among -current collators on system chains as the path towards an invulnerable slot is almost impossible to -pursue. From a technical standpoint, nothing is preventing a permissionless collator, or anyone for -that matter, from submitting a referendum to remove one collator from the invulnerable set and add -themselves in their place. However, as it quickly becomes obvious, such a referendum would be very -difficult to pass under normal circumstances.
The first reason this would be contentious is that there is no significant difference between -collators with good performance. There is no reasonable way to keep track of arbitrary data on-chain -which could clearly and consistently distinguish between one collator or another. Collators that -perform well propose blocks when they are supposed to and that is what is being tracked on-chain. -Any other metrics for performance are arbitrary as far as the runtime logic is concerned and should -be reasoned upon by humans using public discussion and a referendum.
The second reason for this is the inherently social aspect of this action. Even just proposing the -referendum would be perceived as an attack on a specific collator in the set, singling them out, -when in reality the proposer likely just wants to be part of the set and doesn't necessarily care -who is kicked. In order to consolidate their position, the other invulnerables will rally behind the -one that was challenged and the bid to replace one invulnerable will probably fail.
Existing invulnerables have a vested interest in protecting any other invulnerable from such attacks -so that they themselves would be protected if need be. The existing collator set has already -demonstrated that they can work together and subvert the free market mechanism offered by the -runtime when they agreed to not outbid each other on permissionless slots after the new collator -selection mechanism was introduced.
The existing invulnerable set on a given system chain are there for a reason; they have demonstrated -reliability in the past and were rewarded by governance with invulnerable slots and a bounty to -cover their expenses. This means they have a solid reputation and a strong say in governance over -matters related to collation. The optics of a permissionless collator actively challenging an -invulnerable, even when it's justified, combined with the support of other invulnerables, make the -invulnerable set de facto immutable.
While there should be strong guarantees of stability for invulnerables, they should not be a closed -circle. The aim of this RFC is to provide a clear, reasonable, fair, and socially acceptable path -for a permissionless collator with a proven track record to become an invulnerable while preserving -the stability of the invulnerable set of a system parachain.
This RFC proposes a periodic, mandatory, round-robin, two-round election mechanism for -invulnerables.
The election should be implemented on top of the current logic in the collator-selection pallet. -In this mechanism, candidates would register for the first round of the next election by placing -deposits.
When the period between elections passes, the first round of the election starts with every -candidate that registered, excluding the incumbent, as an option on the ballot. Votes should be -expressed using tokens which should not be available for other transactions while the election is -ongoing in order to introduce some opportunity cost to voting. After a certain amount of time -passes, the election closes and the candidate who wins the first round of the election advances to -the second and final round of the election. The deposits held for voting in the first round must be -released before the second round.
In the second round of the election, the winner of the first round has the chance to replace the -invulnerable currently holding the slot. A referendum is submitted to replace the incumbent with the -winner of the first round of the election, turning the second round of the election into a -conviction-voting compatible referendum. If the referendum fails, the incumbent keeps their slot.
The period between elections should be configurable at the collator-selection pallet level. A full -election cycle ends when the pallet held an election for every single invulnerable slot. To qualify -for the ballot, candidates must have been collating for at least one period from a permissionless -slot or be the incumbent.
The first major drawback of this proposal is that it would put more responsibility on governance by -having people vote regularly in order to maintain the invulnerable collator set on each chain. Today -the collator-selection pallet employs a fire-and-forget system where the invulnerables are chosen -once by governance vote. Although in theory governance can always intervene to elect new -invulnerables, for the reasons stated in this RFC this is not the case in practice. Moving away from -this system means more action is needed from governance to ensure the stability of the invulnerable -collator sets on each system chain, which automatically increases the probability of errors. -However, governance is the ultimate source of truth on-chain and there is a lot more at stake in the -hands of governance than the invulnerable collator sets on system chains, so I think this risk is -acceptable.
The second drawback of this proposal is the imperfect voting mechanism. Probably the simplest and -most fair voting system for this scenario would have been First Past the Post, where all candidates -participate in a single election round and the candidate with the most votes wins the election -outright. However, the downside of such a system is the technical complexity behind running such an -election on-chain. This election mechanism would require a multiple choice referendum implementation -in the collator-selection pallet or at the system level somewhere else (e.g. on the Collectives -chain), which would be a mix between the conviction-voting and staking pallets and would -possibly communicate with all system chains via XCM. While this voting system could be useful in -other contexts as well, I don't think it's worth conditioning the invulnerable collator redesign on -a separate implementation of the multiple choice voting system when the Two-Round proposed achieves -the objectives of this RFC.
The chain will have to run extrinsics to start and end elections periodically, but the impact in -terms of weight and PoV size is negligible.
The invulnerables will be the most affected group, as they will have to now compete in elections -periodically to secure their spots. Permissionless candidates will now have a clear, though not -guaranteed, path towards becoming an invulnerable, at least for a period of time.
Any changes to the election mechanism of invulnerables should be compatible with the current -invulnerable set interaction with the collator set chosen at the session boundary. The current -invulnerable set for each chain can be grandfathered in when upgrading the collator-selection -pallet version.
The main spinoff of this RFC might be a multiple choice poll implementation in a separate pallet to -hold a First Past the Post election instead of the Two-Round System proposed, which would prompt a -migration to the new voting system within the collator-selection pallet. Additionally, a more -complex solution where the voting for all system chains happens in a single place which then sends -XCM responses with election results back to system chains can be implemented in the next iteration -of this RFC.
Preference & Asset Declaration → Paired-exchange Convex Optimization → Interaction Ordering (High-to-Low Exchange Impact) → Global Price Convergence → On-chain Auditability -
The primary stakeholders of this RFC are: -– DOT token holders – as this affects the protocol's treasury -– Entities wishing to submit a referendum on these tracks – as this affects the referendum's timeline -– Projects with governance app integrations – see Performance, Ergonomics and Compatibility section below
#![allow(unused)] -fn main() { -type Proof = (Signature, Signature, ..); -}
rust -"POP_"|account_id -
rust -account_id -