Offchain signing (#5182)

* New approach to offchain signing.

* Use in im-online

* Rewrite to use Account<T>

* DRY signing.

* Implement send_raw_unsigned_transaction

* WiP

* Expunge LocalCall

* Expunge LocalCall

* Fix compilation.

* Solve call.

* Make it compile again.

* Finalize implementation.

* Change CreateTransaction

* Clear CreateTransaction.

* Add price payload

* Send raw transaction

* Submit signed payload / unsigned transaction (WIP)

* Supertrait requirements on T::Signature

* Validate signature of payload on an unsigned transaction

* Fix encoding - part 1

* Make it compile.

* Fix compilation of unsigned validator.

* Pass price payload to the transaction

* Make block number part of the signed payload

* Send signed transaction

* Implement all_accounts, any_account

* Fix formatting

* Implement submit_transaction

* Submit signed transaction (ForAll, ForAny)

* Fix formatting

* Implement CreateSignedTransaction

* Move sign and verify to AppCrypto

* Sign transaction

* Call `use_encoded`

* Remove SubmitAndSignTransaction

* Implement runtime using new SigningTypes

* Adapt offchain example to changes

* Fix im-online pallet

* Quick fix: rename AuthorityId2

* Fix offchain example tests

* Add a comment on why keystore is required in unsigned transaction test

* Use UintAuthorityId instead of u64

* WIP

* Remove IdentifyAccount from UintAuthorityId

* Implement PublicWrapper type

* Fix im-online tests

* Fix runtime test

* Bump spec version

* Fix executor tests

* Rename ImOnlineAuthId -> ImOnlineAuthorityId and formatting

* Fix merge

* Documentation

* Revert u64 -> UintAuthorityId conversion

* Fix string errors

* Document public members in offchain module

* Introduce SubmitTransaction

* Update pallets to use SubmitTransaction

* WIP

* Use SubmitTransaction in offchain

* Use `submit_unsigned_transaction`

* Fix tests

* Update docs

* Remove SigningTypes requirement from `SendTransactionTypes`

* Fix tests

* Update frame/system/src/offchain.rs

Co-Authored-By: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Update frame/system/src/offchain.rs

Co-Authored-By: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Update frame/example-offchain-worker/src/tests.rs

Co-Authored-By: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Update frame/system/src/offchain.rs

Co-Authored-By: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Update frame/system/src/offchain.rs

Co-Authored-By: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Remove leftover from previous iterations

* Change enum to struct

* Remove public

* Move mock to node/executor/tests

* Cleanup test-helpers

* Make `application-crypto` `std` feature internal

The macros should not generate code that requires that the calling crate
has a feature with the name `std` defined.

* Revert cargo lock update

* Use TestAuthorityId from common

* Restore members of account to public

* Tidy up imports

* Fix benchmarking pallet

* Add tests demonstrating ForAll, ForAny on signer

* Move definition of AppCrypto

in example-offchain-worker
from tests to mod::crypto

* Cleanup stray comment

* Fix ValidTransaction

* Re-fix CreateSignedTransaction

* Address PR feedback

* Add can_sign method to signer

* Propagate error

* Improve documentation

* Fix vec! macro not available

* Document SendTransactiontypes

* Add some docs.

* Split signing examples

* Add tests for signing examples

* WIP can_sign - PR feedback

* WIP

* Split for_any / for_all into different calls

* Verify payload and signature in test

* Fix can_sign implementation

* Fix impl_version

* Import Box from sp_std

* Create issues for TODOs

* Ignore doctest.

* Add test directly to system. Adjust UintTypes.

* Add some tests to account filtering.

* Remove code samples and point to example offchain worker

* Fix doc links

* Fix im-online tests using signatures.

Co-authored-by: Tomasz Drwięga <tomasz@parity.io>
Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>
Co-authored-by: Bastian Köcher <git@kchr.de>

substrate/frame/example-offchain-worker/src/lib.rs

@@ -22,12 +22,12 @@
 //! Run `cargo doc --package pallet-example-offchain-worker --open` to view this module's
 //! documentation.
 //!
-//! - \[`pallet_example_offchain_worker::Trait`](./trait.Trait.html)
-//! - \[`Call`](./enum.Call.html)
-//! - \[`Module`](./struct.Module.html)
+//! - [`pallet_example_offchain_worker::Trait`](./trait.Trait.html)
+//! - [`Call`](./enum.Call.html)
+//! - [`Module`](./struct.Module.html)
 //!
 //!
-//! \## Overview
+//! ## Overview
 //!
 //! In this example we are going to build a very simplistic, naive and definitely NOT
 //! production-ready oracle for BTC/USD price.
@@ -40,15 +40,24 @@
 //! one unsigned transaction floating in the network.
 #![cfg_attr(not(feature = "std"), no_std)]
 
+use frame_system::{
+	self as system,
+	ensure_signed,
+	ensure_none,
+	offchain::{
+		AppCrypto, CreateSignedTransaction, SendUnsignedTransaction,
+		SignedPayload, SigningTypes, Signer, SubmitTransaction,
+	}
+};
 use frame_support::{
 	debug,
 	dispatch::DispatchResult, decl_module, decl_storage, decl_event,
 	traits::Get,
 	weights::{SimpleDispatchInfo, MINIMUM_WEIGHT},
 };
-use frame_system::{self as system, ensure_signed, ensure_none, offchain};
 use sp_core::crypto::KeyTypeId;
 use sp_runtime::{
+	RuntimeDebug,
 	offchain::{http, Duration, storage::StorageValueRef},
 	traits::Zero,
 	transaction_validity::{
@@ -56,6 +65,7 @@ use sp_runtime::{
 		TransactionPriority,
 	},
 };
+use codec::{Encode, Decode};
 use sp_std::vec::Vec;
 use lite_json::json::JsonValue;
 
@@ -76,18 +86,25 @@ pub const KEY_TYPE: KeyTypeId = KeyTypeId(*b"btc!");
 /// the types with this pallet-specific identifier.
 pub mod crypto {
 	use super::KEY_TYPE;
-	use sp_runtime::app_crypto::{app_crypto, sr25519};
+	use sp_runtime::{
+		app_crypto::{app_crypto, sr25519},
+		traits::Verify,
+	};
+	use sp_core::sr25519::Signature as Sr25519Signature;
 	app_crypto!(sr25519, KEY_TYPE);
+
+	pub struct TestAuthId;
+	impl frame_system::offchain::AppCrypto<<Sr25519Signature as Verify>::Signer, Sr25519Signature> for TestAuthId {
+		type RuntimeAppPublic = Public;
+		type GenericSignature = sp_core::sr25519::Signature;
+		type GenericPublic = sp_core::sr25519::Public;
+	}
 }
 
 /// This pallet's configuration trait
-pub trait Trait: frame_system::Trait {
-	/// The type to sign and submit transactions.
-	type SubmitSignedTransaction:
-		offchain::SubmitSignedTransaction<Self, <Self as Trait>::Call>;
-	/// The type to submit unsigned transactions.
-	type SubmitUnsignedTransaction:
-		offchain::SubmitUnsignedTransaction<Self, <Self as Trait>::Call>;
+pub trait Trait: CreateSignedTransaction<Call<Self>> {
+	/// The identifier type for an offchain worker.
+	type AuthorityId: AppCrypto<Self::Public, Self::Signature>;
 
 	/// The overarching event type.
 	type Event: From<Event<Self>> + Into<<Self as frame_system::Trait>::Event>;
@@ -115,6 +132,21 @@ pub trait Trait: frame_system::Trait {
 	type UnsignedPriority: Get<TransactionPriority>;
 }
 
+/// Payload used by this example crate to hold price
+/// data required to submit a transaction.
+#[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug)]
+pub struct PricePayload<Public, BlockNumber> {
+	block_number: BlockNumber,
+	price: u32,
+	public: Public,
+}
+
+impl<T: SigningTypes> SignedPayload<T> for PricePayload<T::Public, T::BlockNumber> {
+	fn public(&self) -> T::Public {
+		self.public.clone()
+	}
+}
+
 decl_storage! {
 	trait Store for Module<T: Trait> as ExampleOffchainWorker {
 		/// A vector of recently submitted prices.
@@ -196,6 +228,22 @@ decl_module! {
 			Ok(())
 		}
 
+		#[weight = SimpleDispatchInfo::FixedNormal(10_000)]
+		pub fn submit_price_unsigned_with_signed_payload(
+			origin,
+			price_payload: PricePayload<T::Public, T::BlockNumber>,
+			_signature: T::Signature,
+		) -> DispatchResult {
+			// This ensures that the function can only be called via unsigned transaction.
+			ensure_none(origin)?;
+			// Add the price to the on-chain list, but mark it as coming from an empty address.
+			Self::add_price(Default::default(), price_payload.price);
+			// now increment the block number at which we expect next unsigned transaction.
+			let current_block = <system::Module<T>>::block_number();
+			<NextUnsignedAt<T>>::put(current_block + T::UnsignedInterval::get());
+			Ok(())
+		}
+
 		/// Offchain Worker entry point.
 		///
 		/// By implementing `fn offchain_worker` within `decl_module!` you declare a new offchain
@@ -236,7 +284,9 @@ decl_module! {
 			let should_send = Self::choose_transaction_type(block_number);
 			let res = match should_send {
 				TransactionType::Signed => Self::fetch_price_and_send_signed(),
-				TransactionType::Unsigned => Self::fetch_price_and_send_unsigned(block_number),
+				TransactionType::UnsignedForAny => Self::fetch_price_and_send_unsigned_for_any_account(block_number),
+				TransactionType::UnsignedForAll => Self::fetch_price_and_send_unsigned_for_all_accounts(block_number),
+				TransactionType::Raw => Self::fetch_price_and_send_raw_unsigned(block_number),
 				TransactionType::None => Ok(()),
 			};
 			if let Err(e) = res {
@@ -248,7 +298,9 @@ decl_module! {
 
 enum TransactionType {
 	Signed,
-	Unsigned,
+	UnsignedForAny,
+	UnsignedForAll,
+	Raw,
 	None,
 }
 
@@ -311,12 +363,11 @@ impl<T: Trait> Module<T> {
 				// transactions in a row. If a strict order is desired, it's better to use
 				// the storage entry for that. (for instance store both block number and a flag
 				// indicating the type of next transaction to send).
-				let send_signed = block_number % 2.into() == Zero::zero();
-				if send_signed {
-					TransactionType::Signed
-				} else {
-					TransactionType::Unsigned
-				}
+				let transaction_type = block_number % 3.into();
+				if transaction_type == Zero::zero() { TransactionType::Signed }
+				else if transaction_type == T::BlockNumber::from(1) { TransactionType::UnsignedForAny }
+				else if transaction_type == T::BlockNumber::from(2) { TransactionType::UnsignedForAll }
+				else { TransactionType::Raw }
 			},
 			// We are in the grace period, we should not send a transaction this time.
 			Err(RECENTLY_SENT) => TransactionType::None,
@@ -331,44 +382,43 @@ impl<T: Trait> Module<T> {
 
 	/// A helper function to fetch the price and send signed transaction.
 	fn fetch_price_and_send_signed() -> Result<(), &'static str> {
-		use system::offchain::SubmitSignedTransaction;
-		// Firstly we check if there are any accounts in the local keystore that are capable of
-		// signing the transaction.
-		// If not it doesn't even make sense to make external HTTP requests, since we won't be able
-		// to put the results back on-chain.
-		if !T::SubmitSignedTransaction::can_sign() {
+		use frame_system::offchain::SendSignedTransaction;
+
+		let signer = Signer::<T, T::AuthorityId>::all_accounts();
+		if !signer.can_sign() {
 			return Err(
 				"No local accounts available. Consider adding one via `author_insertKey` RPC."
 			)?
 		}
-
 		// Make an external HTTP request to fetch the current price.
 		// Note this call will block until response is received.
 		let price = Self::fetch_price().map_err(|_| "Failed to fetch price")?;
 
-		// Received price is wrapped into a call to `submit_price` public function of this pallet.
-		// This means that the transaction, when executed, will simply call that function passing
-		// `price` as an argument.
-		let call = Call::submit_price(price);
-
-		// Using `SubmitSignedTransaction` associated type we create and submit a transaction
+		// Using `send_signed_transaction` associated type we create and submit a transaction
 		// representing the call, we've just created.
 		// Submit signed will return a vector of results for all accounts that were found in the
 		// local keystore with expected `KEY_TYPE`.
-		let results = T::SubmitSignedTransaction::submit_signed(call);
+		let results = signer.send_signed_transaction(
+			|_account| {
+				// Received price is wrapped into a call to `submit_price` public function of this pallet.
+				// This means that the transaction, when executed, will simply call that function passing
+				// `price` as an argument.
+				Call::submit_price(price)
+			}
+		);
+
 		for (acc, res) in &results {
 			match res {
-				Ok(()) => debug::info!("[{:?}] Submitted price of {} cents", acc, price),
-				Err(e) => debug::error!("[{:?}] Failed to submit transaction: {:?}", acc, e),
+				Ok(()) => debug::info!("[{:?}] Submitted price of {} cents", acc.id, price),
+				Err(e) => debug::error!("[{:?}] Failed to submit transaction: {:?}", acc.id, e),
 			}
 		}
 
 		Ok(())
 	}
 
-	/// A helper function to fetch the price and send unsigned transaction.
-	fn fetch_price_and_send_unsigned(block_number: T::BlockNumber) -> Result<(), &'static str> {
-		use system::offchain::SubmitUnsignedTransaction;
+	/// A helper function to fetch the price and send a raw unsigned transaction.
+	fn fetch_price_and_send_raw_unsigned(block_number: T::BlockNumber) -> Result<(), &'static str> {
 		// Make sure we don't fetch the price if unsigned transaction is going to be rejected
 		// anyway.
 		let next_unsigned_at = <NextUnsignedAt<T>>::get();
@@ -385,14 +435,101 @@ impl<T: Trait> Module<T> {
 		// passing `price` as an argument.
 		let call = Call::submit_price_unsigned(block_number, price);
 
-		// Now let's create an unsigned transaction out of this call and submit it to the pool.
+		// Now let's create a transaction out of this call and submit it to the pool.
+		// Here we showcase two ways to send an unsigned transaction / unsigned payload (raw)
+		//
 		// By default unsigned transactions are disallowed, so we need to whitelist this case
 		// by writing `UnsignedValidator`. Note that it's EXTREMELY important to carefuly
 		// implement unsigned validation logic, as any mistakes can lead to opening DoS or spam
 		// attack vectors. See validation logic docs for more details.
-		T::SubmitUnsignedTransaction::submit_unsigned(call)
-			.map_err(|()| "Unable to submit unsigned transaction.".into())
+		//
+		SubmitTransaction::<T, Call<T>>::submit_unsigned_transaction(call.into())
+			.map_err(|()| "Unable to submit unsigned transaction.")?;
 
+		Ok(())
+	}
+
+	/// A helper function to fetch the price, sign payload and send an unsigned transaction
+	fn fetch_price_and_send_unsigned_for_any_account(block_number: T::BlockNumber) -> Result<(), &'static str> {
+		// Make sure we don't fetch the price if unsigned transaction is going to be rejected
+		// anyway.
+		let next_unsigned_at = <NextUnsignedAt<T>>::get();
+		if next_unsigned_at > block_number {
+			return Err("Too early to send unsigned transaction")
+		}
+
+		// Make an external HTTP request to fetch the current price.
+		// Note this call will block until response is received.
+		let price = Self::fetch_price().map_err(|_| "Failed to fetch price")?;
+
+		// Received price is wrapped into a call to `submit_price_unsigned` public function of this
+		// pallet. This means that the transaction, when executed, will simply call that function
+		// passing `price` as an argument.
+		let call = Call::submit_price_unsigned(block_number, price);
+
+		// Now let's create a transaction out of this call and submit it to the pool.
+		// Here we showcase two ways to send an unsigned transaction with a signed payload
+		SubmitTransaction::<T, Call<T>>::submit_unsigned_transaction(call.into())
+			.map_err(|()| "Unable to submit unsigned transaction.")?;
+
+		// -- Sign using any account
+		let (_, result) = Signer::<T, T::AuthorityId>::any_account().send_unsigned_transaction(
+			|account| PricePayload {
+				price,
+				block_number,
+				public: account.public.clone()
+			},
+			|payload, signature| {
+				Call::submit_price_unsigned_with_signed_payload(payload, signature)
+			}
+		).ok_or("No local accounts accounts available.")?;
+		result.map_err(|()| "Unable to submit transaction")?;
+
+		Ok(())
+	}
+
+	/// A helper function to fetch the price, sign payload and send an unsigned transaction
+	fn fetch_price_and_send_unsigned_for_all_accounts(block_number: T::BlockNumber) -> Result<(), &'static str> {
+		// Make sure we don't fetch the price if unsigned transaction is going to be rejected
+		// anyway.
+		let next_unsigned_at = <NextUnsignedAt<T>>::get();
+		if next_unsigned_at > block_number {
+			return Err("Too early to send unsigned transaction")
+		}
+
+		// Make an external HTTP request to fetch the current price.
+		// Note this call will block until response is received.
+		let price = Self::fetch_price().map_err(|_| "Failed to fetch price")?;
+
+		// Received price is wrapped into a call to `submit_price_unsigned` public function of this
+		// pallet. This means that the transaction, when executed, will simply call that function
+		// passing `price` as an argument.
+		let call = Call::submit_price_unsigned(block_number, price);
+
+		// Now let's create a transaction out of this call and submit it to the pool.
+		// Here we showcase two ways to send an unsigned transaction with a signed payload
+		SubmitTransaction::<T, Call<T>>::submit_unsigned_transaction(call.into())
+			.map_err(|()| "Unable to submit unsigned transaction.")?;
+
+		// -- Sign using all accounts
+		let transaction_results = Signer::<T, T::AuthorityId>::all_accounts()
+			.send_unsigned_transaction(
+				|account| PricePayload {
+					price,
+					block_number,
+					public: account.public.clone()
+				},
+				|payload, signature| {
+					Call::submit_price_unsigned_with_signed_payload(payload, signature)
+				}
+			);
+		for (_account_id, result) in transaction_results.into_iter() {
+			if result.is_err() {
+				return Err("Unable to submit transaction");
+			}
+		}
+
+		Ok(())
 	}
 
 	/// Fetch current price and return the result in cents.
@@ -507,6 +644,58 @@ impl<T: Trait> Module<T> {
 			Some(prices.iter().fold(0_u32, |a, b| a.saturating_add(*b)) / prices.len() as u32)
 		}
 	}
+
+	fn validate_transaction_parameters(
+		block_number: &T::BlockNumber,
+		new_price: &u32,
+	) -> TransactionValidity {
+		// Now let's check if the transaction has any chance to succeed.
+		let next_unsigned_at = <NextUnsignedAt<T>>::get();
+		if &next_unsigned_at > block_number {
+			return InvalidTransaction::Stale.into();
+		}
+		// Let's make sure to reject transactions from the future.
+		let current_block = <system::Module<T>>::block_number();
+		if &current_block < block_number {
+			return InvalidTransaction::Future.into();
+		}
+
+		// We prioritize transactions that are more far away from current average.
+		//
+		// Note this doesn't make much sense when building an actual oracle, but this example
+		// is here mostly to show off offchain workers capabilities, not about building an
+		// oracle.
+		let avg_price = Self::average_price()
+			.map(|price| if &price > new_price { price - new_price } else { new_price - price })
+			.unwrap_or(0);
+
+		ValidTransaction::with_tag_prefix("ExampleOffchainWorker")
+			// We set base priority to 2**20 and hope it's included before any other
+			// transactions in the pool. Next we tweak the priority depending on how much
+			// it differs from the current average. (the more it differs the more priority it
+			// has).
+			.priority(T::UnsignedPriority::get().saturating_add(avg_price as _))
+			// This transaction does not require anything else to go before into the pool.
+			// In theory we could require `previous_unsigned_at` transaction to go first,
+			// but it's not necessary in our case.
+			//.and_requires()
+			// We set the `provides` tag to be the same as `next_unsigned_at`. This makes
+			// sure only one transaction produced after `next_unsigned_at` will ever
+			// get to the transaction pool and will end up in the block.
+			// We can still have multiple transactions compete for the same "spot",
+			// and the one with higher priority will replace other one in the pool.
+			.and_provides(next_unsigned_at)
+			// The transaction is only valid for next 5 blocks. After that it's
+			// going to be revalidated by the pool.
+			.longevity(5)
+			// It's fine to propagate that transaction to other peers, which means it can be
+			// created even by nodes that don't produce blocks.
+			// Note that sometimes it's better to keep it for yourself (if you are the block
+			// producer), since for instance in some schemes others may copy your solution and
+			// claim a reward.
+			.propagate(true)
+			.build()
+	}
 }
 
 #[allow(deprecated)] // ValidateUnsigned
@@ -523,54 +712,16 @@ impl<T: Trait> frame_support::unsigned::ValidateUnsigned for Module<T> {
 		call: &Self::Call,
 	) -> TransactionValidity {
 		// Firstly let's check that we call the right function.
-		if let Call::submit_price_unsigned(block_number, new_price) = call {
-			// Now let's check if the transaction has any chance to succeed.
-			let next_unsigned_at = <NextUnsignedAt<T>>::get();
-			if &next_unsigned_at > block_number {
-				return InvalidTransaction::Stale.into();
+		if let Call::submit_price_unsigned_with_signed_payload(
+			ref payload, ref signature
+		) = call {
+			let signature_valid = SignedPayload::<T>::verify::<T::AuthorityId>(payload, signature.clone());
+			if !signature_valid {
+				return InvalidTransaction::BadProof.into();
 			}
-			// Let's make sure to reject transactions from the future.
-			let current_block = <system::Module<T>>::block_number();
-			if &current_block < block_number {
-				return InvalidTransaction::Future.into();
-			}
-
-			// We prioritize transactions that are more far away from current average.
-			//
-			// Note this doesn't make much sense when building an actual oracle, but this example
-			// is here mostly to show off offchain workers capabilities, not about building an
-			// oracle.
-			let avg_price = Self::average_price()
-				.map(|price| if &price > new_price { price - new_price } else { new_price - price })
-				.unwrap_or(0);
-
-			ValidTransaction::with_tag_prefix("ExampleOffchainWorker")
-				// We set base priority to 2**20 to make sure it's included before any other
-				// transactions in the pool. Next we tweak the priority depending on how much
-				// it differs from the current average. (the more it differs the more priority it
-				// has).
-				.priority(T::UnsignedPriority::get().saturating_add(avg_price as _))
-				// This transaction does not require anything else to go before into the pool.
-				// In theory we could require `previous_unsigned_at` transaction to go first,
-				// but it's not necessary in our case.
-				//.and_requires()
-
-				// We set the `provides` tag to be the same as `next_unsigned_at`. This makes
-				// sure only one transaction produced after `next_unsigned_at` will ever
-				// get to the transaction pool and will end up in the block.
-				// We can still have multiple transactions compete for the same "spot",
-				// and the one with higher priority will replace other one in the pool.
-				.and_provides(next_unsigned_at)
-				// The transaction is only valid for next 5 blocks. After that it's
-				// going to be revalidated by the pool.
-				.longevity(5)
-				// It's fine to propagate that transaction to other peers, which means it can be
-				// created even by nodes that don't produce blocks.
-				// Note that sometimes it's better to keep it for yourself (if you are the block
-				// producer), since for instance in some schemes others may copy your solution and
-				// claim a reward.
-				.propagate(true)
-				.build()
+			Self::validate_transaction_parameters(&payload.block_number, &payload.price)
+		} else if let Call::submit_price_unsigned(block_number, new_price) = call {
+			Self::validate_transaction_parameters(block_number, new_price)
 		} else {
 			InvalidTransaction::Call.into()
 		}

substrate/frame/example-offchain-worker/src/tests.rs

@@ -16,7 +16,7 @@
 
 use crate::*;
 
-use codec::Decode;
+use codec::{Encode, Decode};
 use frame_support::{
 	assert_ok, impl_outer_origin, parameter_types,
 	weights::Weight,
@@ -24,13 +24,17 @@ use frame_support::{
 use sp_core::{
 	H256,
 	offchain::{OffchainExt, TransactionPoolExt, testing},
+	sr25519::Signature,
 	testing::KeyStore,
 	traits::KeystoreExt,
 };
 use sp_runtime::{
 	Perbill, RuntimeAppPublic,
 	testing::{Header, TestXt},
-	traits::{BlakeTwo256, IdentityLookup, Extrinsic as ExtrinsicsT},
+	traits::{
+		BlakeTwo256, IdentityLookup, Extrinsic as ExtrinsicT,
+		IdentifyAccount, Verify,
+	},
 };
 
 impl_outer_origin! {
@@ -40,7 +44,7 @@ impl_outer_origin! {
 // For testing the module, we construct most of a mock runtime. This means
 // first constructing a configuration type (`Test`) which `impl`s each of the
 // configuration traits of modules we want to use.
-#[derive(Clone, Eq, PartialEq)]
+#[derive(Clone, Eq, PartialEq, Encode, Decode)]
 pub struct Test;
 parameter_types! {
 	pub const BlockHashCount: u64 = 250;
@@ -72,22 +76,29 @@ impl frame_system::Trait for Test {
 }
 
 type Extrinsic = TestXt<Call<Test>, ()>;
-type SubmitTransaction = frame_system::offchain::TransactionSubmitter<
-	crypto::Public,
-	Test,
-	Extrinsic
->;
+type AccountId = <<Signature as Verify>::Signer as IdentifyAccount>::AccountId;
 
-impl frame_system::offchain::CreateTransaction<Test, Extrinsic> for Test {
-	type Public = sp_core::sr25519::Public;
-	type Signature = sp_core::sr25519::Signature;
+impl frame_system::offchain::SigningTypes for Test {
+	type Public = <Signature as Verify>::Signer;
+	type Signature = Signature;
+}
 
-	fn create_transaction<F: frame_system::offchain::Signer<Self::Public, Self::Signature>>(
-		call: <Extrinsic as ExtrinsicsT>::Call,
-		_public: Self::Public,
-		_account: <Test as frame_system::Trait>::AccountId,
-		nonce: <Test as frame_system::Trait>::Index,
-	) -> Option<(<Extrinsic as ExtrinsicsT>::Call, <Extrinsic as ExtrinsicsT>::SignaturePayload)> {
+impl<LocalCall> frame_system::offchain::SendTransactionTypes<LocalCall> for Test where
+	Call<Test>: From<LocalCall>,
+{
+	type OverarchingCall = Call<Test>;
+	type Extrinsic = Extrinsic;
+}
+
+impl<LocalCall> frame_system::offchain::CreateSignedTransaction<LocalCall> for Test where
+	Call<Test>: From<LocalCall>,
+{
+	fn create_transaction<C: frame_system::offchain::AppCrypto<Self::Public, Self::Signature>>(
+		call: Call<Test>,
+		_public: <Signature as Verify>::Signer,
+		_account: AccountId,
+		nonce: u64,
+	) -> Option<(Call<Test>, <Extrinsic as ExtrinsicT>::SignaturePayload)> {
 		Some((call, (nonce, ())))
 	}
 }
@@ -100,9 +111,8 @@ parameter_types! {
 
 impl Trait for Test {
 	type Event = ();
+	type AuthorityId = crypto::TestAuthId;
 	type Call = Call<Test>;
-	type SubmitSignedTransaction = SubmitTransaction;
-	type SubmitUnsignedTransaction = SubmitTransaction;
 	type GracePeriod = GracePeriod;
 	type UnsignedInterval = UnsignedInterval;
 	type UnsignedPriority = UnsignedPriority;
@@ -172,18 +182,128 @@ fn should_submit_signed_transaction_on_chain() {
 }
 
 #[test]
-fn should_submit_unsigned_transaction_on_chain() {
+fn should_submit_unsigned_transaction_on_chain_for_any_account() {
+	const PHRASE: &str = "news slush supreme milk chapter athlete soap sausage put clutch what kitten";
 	let (offchain, offchain_state) = testing::TestOffchainExt::new();
 	let (pool, pool_state) = testing::TestTransactionPoolExt::new();
+
+	let keystore = KeyStore::new();
+
+	keystore.write().sr25519_generate_new(
+		crate::crypto::Public::ID,
+		Some(&format!("{}/hunter1", PHRASE))
+	).unwrap();
+
 	let mut t = sp_io::TestExternalities::default();
 	t.register_extension(OffchainExt::new(offchain));
 	t.register_extension(TransactionPoolExt::new(pool));
+	t.register_extension(KeystoreExt(keystore.clone()));
+
+	price_oracle_response(&mut offchain_state.write());
+
+	let public_key = keystore.read()
+		.sr25519_public_keys(crate::crypto::Public::ID)
+		.get(0)
+		.unwrap()
+		.clone();
+
+	let price_payload = PricePayload {
+		block_number: 1,
+		price: 15523,
+		public: <Test as SigningTypes>::Public::from(public_key),
+	};
+
+	// let signature = price_payload.sign::<crypto::TestAuthId>().unwrap();
+	t.execute_with(|| {
+		// when
+		Example::fetch_price_and_send_unsigned_for_any_account(1).unwrap();
+		// then
+		let tx = pool_state.write().transactions.pop().unwrap();
+		let tx = Extrinsic::decode(&mut &*tx).unwrap();
+		assert_eq!(tx.signature, None);
+		if let Call::submit_price_unsigned_with_signed_payload(body, signature) = tx.call {
+			assert_eq!(body, price_payload);
+
+			let signature_valid = <PricePayload<
+				<Test as SigningTypes>::Public,
+				<Test as frame_system::Trait>::BlockNumber
+					> as SignedPayload<Test>>::verify::<crypto::TestAuthId>(&price_payload, signature);
+
+			assert!(signature_valid);
+		}
+	});
+}
+
+#[test]
+fn should_submit_unsigned_transaction_on_chain_for_all_accounts() {
+	const PHRASE: &str = "news slush supreme milk chapter athlete soap sausage put clutch what kitten";
+	let (offchain, offchain_state) = testing::TestOffchainExt::new();
+	let (pool, pool_state) = testing::TestTransactionPoolExt::new();
+
+	let keystore = KeyStore::new();
+
+	keystore.write().sr25519_generate_new(
+		crate::crypto::Public::ID,
+		Some(&format!("{}/hunter1", PHRASE))
+	).unwrap();
+
+	let mut t = sp_io::TestExternalities::default();
+	t.register_extension(OffchainExt::new(offchain));
+	t.register_extension(TransactionPoolExt::new(pool));
+	t.register_extension(KeystoreExt(keystore.clone()));
+
+	price_oracle_response(&mut offchain_state.write());
+
+	let public_key = keystore.read()
+		.sr25519_public_keys(crate::crypto::Public::ID)
+		.get(0)
+		.unwrap()
+		.clone();
+
+	let price_payload = PricePayload {
+		block_number: 1,
+		price: 15523,
+		public: <Test as SigningTypes>::Public::from(public_key),
+	};
+
+	// let signature = price_payload.sign::<crypto::TestAuthId>().unwrap();
+	t.execute_with(|| {
+		// when
+		Example::fetch_price_and_send_unsigned_for_all_accounts(1).unwrap();
+		// then
+		let tx = pool_state.write().transactions.pop().unwrap();
+		let tx = Extrinsic::decode(&mut &*tx).unwrap();
+		assert_eq!(tx.signature, None);
+		if let Call::submit_price_unsigned_with_signed_payload(body, signature) = tx.call {
+			assert_eq!(body, price_payload);
+
+			let signature_valid = <PricePayload<
+				<Test as SigningTypes>::Public,
+				<Test as frame_system::Trait>::BlockNumber
+					> as SignedPayload<Test>>::verify::<crypto::TestAuthId>(&price_payload, signature);
+
+			assert!(signature_valid);
+		}
+	});
+}
+
+#[test]
+fn should_submit_raw_unsigned_transaction_on_chain() {
+	let (offchain, offchain_state) = testing::TestOffchainExt::new();
+	let (pool, pool_state) = testing::TestTransactionPoolExt::new();
+
+	let keystore = KeyStore::new();
+
+	let mut t = sp_io::TestExternalities::default();
+	t.register_extension(OffchainExt::new(offchain));
+	t.register_extension(TransactionPoolExt::new(pool));
+	t.register_extension(KeystoreExt(keystore));
 
 	price_oracle_response(&mut offchain_state.write());
 
 	t.execute_with(|| {
 		// when
-		Example::fetch_price_and_send_unsigned(1).unwrap();
+		Example::fetch_price_and_send_raw_unsigned(1).unwrap();
 		// then
 		let tx = pool_state.write().transactions.pop().unwrap();
 		assert!(pool_state.read().transactions.is_empty());

substrate/frame/im-online/src/lib.rs

@@ -98,7 +98,10 @@ use frame_support::{
 	weights::{SimpleDispatchInfo, MINIMUM_WEIGHT},
 };
 use frame_system::{self as system, ensure_none};
-use frame_system::offchain::SubmitUnsignedTransaction;
+use frame_system::offchain::{
+	SendTransactionTypes,
+	SubmitTransaction,
+};
 
 pub mod sr25519 {
 	mod app_sr25519 {
@@ -221,19 +224,13 @@ pub struct Heartbeat<BlockNumber>
 	pub authority_index: AuthIndex,
 }
 
-pub trait Trait: frame_system::Trait + pallet_session::historical::Trait {
+pub trait Trait: SendTransactionTypes<Call<Self>> + pallet_session::historical::Trait {
 	/// The identifier type for an authority.
 	type AuthorityId: Member + Parameter + RuntimeAppPublic + Default + Ord;
 
 	/// The overarching event type.
 	type Event: From<Event<Self>> + Into<<Self as frame_system::Trait>::Event>;
 
-	/// A dispatchable call type.
-	type Call: From<Call<Self>>;
-
-	/// A transaction submitter.
-	type SubmitTransaction: SubmitUnsignedTransaction<Self, <Self as Trait>::Call>;
-
 	/// An expected duration of the session.
 	///
 	/// This parameter is used to determine the longevity of `heartbeat` transaction
@@ -444,6 +441,7 @@ impl<T: Trait> Module<T> {
 		}
 
 		let session_index = <pallet_session::Module<T>>::current_index();
+
 		Ok(Self::local_authority_keys()
 			.map(move |(authority_index, key)|
 				Self::send_single_heartbeat(authority_index, key, session_index, block_number)
@@ -467,7 +465,9 @@ impl<T: Trait> Module<T> {
 				session_index,
 				authority_index,
 			};
+
 			let signature = key.sign(&heartbeat_data.encode()).ok_or(OffchainErr::FailedSigning)?;
+
 			Ok(Call::heartbeat(heartbeat_data, signature))
 		};
 
@@ -492,7 +492,7 @@ impl<T: Trait> Module<T> {
 					call,
 				);
 
-				T::SubmitTransaction::submit_unsigned(call)
+				SubmitTransaction::<T, Call<T>>::submit_unsigned_transaction(call.into())
 					.map_err(|_| OffchainErr::SubmitTransaction)?;
 
 				Ok(())
@@ -501,9 +501,18 @@ impl<T: Trait> Module<T> {
 	}
 
 	fn local_authority_keys() -> impl Iterator<Item=(u32, T::AuthorityId)> {
-		// we run only when a local authority key is configured
+		// on-chain storage
+		//
+		// At index `idx`:
+		// 1. A (ImOnline) public key to be used by a validator at index `idx` to send im-online
+		//          heartbeats.
 		let authorities = Keys::<T>::get();
+
+		// local keystore
+		//
+		// All `ImOnline` public (+private) keys currently in the local keystore.
 		let mut local_keys = T::AuthorityId::all();
+
 		local_keys.sort();
 
 		authorities.into_iter()
@@ -565,6 +574,11 @@ impl<T: Trait> Module<T> {
 			Keys::<T>::put(keys);
 		}
 	}
+
+	#[cfg(test)]
+	fn set_keys(keys: Vec<T::AuthorityId>) {
+		Keys::<T>::put(&keys)
+	}
 }
 
 impl<T: Trait> sp_runtime::BoundToRuntimeAppPublic for Module<T> {

substrate/frame/im-online/src/mock.rs

@@ -27,7 +27,6 @@ use sp_runtime::testing::{Header, UintAuthorityId, TestXt};
 use sp_runtime::traits::{IdentityLookup, BlakeTwo256, ConvertInto};
 use sp_core::H256;
 use frame_support::{impl_outer_origin, impl_outer_dispatch, parameter_types, weights::Weight};
-
 use frame_system as system;
 impl_outer_origin!{
 	pub enum Origin for Runtime {}
@@ -40,7 +39,11 @@ impl_outer_dispatch! {
 }
 
 thread_local! {
-	pub static VALIDATORS: RefCell<Option<Vec<u64>>> = RefCell::new(Some(vec![1, 2, 3]));
+	pub static VALIDATORS: RefCell<Option<Vec<u64>>> = RefCell::new(Some(vec![
+		1,
+		2,
+		3,
+	]));
 }
 
 pub struct TestSessionManager;
@@ -68,7 +71,6 @@ impl pallet_session::historical::SessionManager<u64, u64> for TestSessionManager
 
 /// An extrinsic type used for tests.
 pub type Extrinsic = TestXt<Call, ()>;
-type SubmitTransaction = frame_system::offchain::TransactionSubmitter<(), Call, Extrinsic>;
 type IdentificationTuple = (u64, u64);
 type Offence = crate::UnresponsivenessOffence<IdentificationTuple>;
 
@@ -90,7 +92,6 @@ pub fn new_test_ext() -> sp_io::TestExternalities {
 	t.into()
 }
 
-
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct Runtime;
 
@@ -168,13 +169,18 @@ parameter_types! {
 impl Trait for Runtime {
 	type AuthorityId = UintAuthorityId;
 	type Event = ();
-	type Call = Call;
-	type SubmitTransaction = SubmitTransaction;
 	type ReportUnresponsiveness = OffenceHandler;
 	type SessionDuration = Period;
 	type UnsignedPriority = UnsignedPriority;
 }
 
+impl<LocalCall> frame_system::offchain::SendTransactionTypes<LocalCall> for Runtime where
+	Call: From<LocalCall>,
+{
+	type OverarchingCall = Call;
+	type Extrinsic = Extrinsic;
+}
+
 /// Im Online module.
 pub type ImOnline = Module<Runtime>;
 pub type System = frame_system::Module<Runtime>;
@@ -184,5 +190,7 @@ pub fn advance_session() {
 	let now = System::block_number().max(1);
 	System::set_block_number(now + 1);
 	Session::rotate_session();
+	let keys = Session::validators().into_iter().map(UintAuthorityId).collect();
+	ImOnline::set_keys(keys);
 	assert_eq!(Session::current_index(), (now / Period::get()) as u32);
 }

substrate/frame/im-online/src/tests.rs

@@ -61,15 +61,15 @@ fn should_report_offline_validators() {
 		let block = 1;
 		System::set_block_number(block);
 		// buffer new validators
-		Session::rotate_session();
+		advance_session();
 		// enact the change and buffer another one
 		let validators = vec![1, 2, 3, 4, 5, 6];
 		VALIDATORS.with(|l| *l.borrow_mut() = Some(validators.clone()));
-		Session::rotate_session();
+		advance_session();
 
 		// when
 		// we end current session and start the next one
-		Session::rotate_session();
+		advance_session();
 
 		// then
 		let offences = OFFENCES.with(|l| l.replace(vec![]));
@@ -89,7 +89,7 @@ fn should_report_offline_validators() {
 		for (idx, v) in validators.into_iter().take(4).enumerate() {
 			let _ = heartbeat(block, 3, idx as u32, v.into()).unwrap();
 		}
-		Session::rotate_session();
+		advance_session();
 
 		// then
 		let offences = OFFENCES.with(|l| l.replace(vec![]));
@@ -174,7 +174,7 @@ fn late_heartbeat_should_fail() {
 	new_test_ext().execute_with(|| {
 		advance_session();
 		// given
-		VALIDATORS.with(|l| *l.borrow_mut() = Some(vec![1, 2, 4, 4, 5, 6]));
+		VALIDATORS.with(|l| *l.borrow_mut() = Some(vec![1, 2, 3, 4, 5, 6]));
 		assert_eq!(Session::validators(), Vec::<u64>::new());
 		// enact the change and buffer another one
 		advance_session();
@@ -315,7 +315,7 @@ fn should_not_send_a_report_if_already_online() {
 		ImOnline::note_uncle(3, 0);
 
 		// when
-		UintAuthorityId::set_all_keys(vec![0]); // all authorities use pallet_session key 0
+		UintAuthorityId::set_all_keys(vec![1, 2, 3]);
 		// we expect error, since the authority is already online.
 		let mut res = ImOnline::send_heartbeats(4).unwrap();
 		assert_eq!(res.next().unwrap().unwrap(), ());

substrate/frame/session/benchmarking/src/mock.rs

@@ -151,11 +151,13 @@ parameter_types! {
 }
 
 pub type Extrinsic = sp_runtime::testing::TestXt<Call, ()>;
-type SubmitTransaction = frame_system::offchain::TransactionSubmitter<
-	sp_runtime::testing::UintAuthorityId,
-	Test,
-	Extrinsic,
->;
+
+impl<C> frame_system::offchain::SendTransactionTypes<C> for Test where
+	Call: From<C>,
+{
+	type OverarchingCall = Call;
+	type Extrinsic = Extrinsic;
+}
 
 impl pallet_staking::Trait for Test {
 	type Currency = Balances;
@@ -174,7 +176,6 @@ impl pallet_staking::Trait for Test {
 	type NextNewSession = Session;
 	type ElectionLookahead = ();
 	type Call = Call;
-	type SubmitTransaction = SubmitTransaction;
 	type MaxNominatorRewardedPerValidator = MaxNominatorRewardedPerValidator;
 	type UnsignedPriority = UnsignedPriority;
 }

substrate/frame/staking/src/lib.rs

@@ -320,7 +320,7 @@ use sp_staking::{
 use sp_runtime::{Serialize, Deserialize};
 use frame_system::{
 	self as system, ensure_signed, ensure_root, ensure_none,
-	offchain::SubmitUnsignedTransaction,
+	offchain::SendTransactionTypes,
 };
 use sp_phragmen::{
 	ExtendedBalance, Assignment, PhragmenScore, PhragmenResult, build_support_map, evaluate_support,
@@ -743,7 +743,7 @@ impl<T: Trait> SessionInterface<<T as frame_system::Trait>::AccountId> for T whe
 	}
 }
 
-pub trait Trait: frame_system::Trait {
+pub trait Trait: frame_system::Trait + SendTransactionTypes<Call<Self>> {
 	/// The staking balance.
 	type Currency: LockableCurrency<Self::AccountId, Moment=Self::BlockNumber>;
 
@@ -804,10 +804,7 @@ pub trait Trait: frame_system::Trait {
 	/// The overarching call type.
 	type Call: Dispatchable + From<Call<Self>> + IsSubType<Module<Self>, Self> + Clone;
 
-	/// A transaction submitter.
-	type SubmitTransaction: SubmitUnsignedTransaction<Self, <Self as Trait>::Call>;
-
-	/// The maximum number of nominators rewarded for each validator.
+	/// The maximum number of nominator rewarded for each validator.
 	///
 	/// For each validator only the `$MaxNominatorRewardedPerValidator` biggest stakers can claim
 	/// their reward. This used to limit the i/o cost for the nominator payout.

substrate/frame/staking/src/mock.rs

@@ -29,7 +29,6 @@ use frame_support::{
 	traits::{Currency, Get, FindAuthor, OnFinalize, OnInitialize},
 	weights::Weight,
 };
-use frame_system::offchain::TransactionSubmitter;
 use sp_io;
 use sp_phragmen::{
 	build_support_map, evaluate_support, reduce, ExtendedBalance, StakedAssignment, PhragmenScore,
@@ -309,13 +308,18 @@ impl Trait for Test {
 	type NextNewSession = Session;
 	type ElectionLookahead = ElectionLookahead;
 	type Call = Call;
-	type SubmitTransaction = SubmitTransaction;
 	type MaxNominatorRewardedPerValidator = MaxNominatorRewardedPerValidator;
 	type UnsignedPriority = UnsignedPriority;
 }
 
+impl<LocalCall> frame_system::offchain::SendTransactionTypes<LocalCall> for Test where
+	Call: From<LocalCall>,
+{
+	type OverarchingCall = Call;
+	type Extrinsic = Extrinsic;
+}
+
 pub type Extrinsic = TestXt<Call, ()>;
-type SubmitTransaction = TransactionSubmitter<(), Test, Extrinsic>;
 
 pub struct ExtBuilder {
 	session_length: BlockNumber,

substrate/frame/staking/src/offchain_election.rs

@@ -19,7 +19,7 @@
 use crate::{
 	Call, CompactAssignments, Module, NominatorIndex, OffchainAccuracy, Trait, ValidatorIndex,
 };
-use frame_system::offchain::SubmitUnsignedTransaction;
+use frame_system::offchain::SubmitTransaction;
 use sp_phragmen::{
 	build_support_map, evaluate_support, reduce, Assignment, ExtendedBalance, PhragmenResult,
 	PhragmenScore,
@@ -117,14 +117,14 @@ pub(crate) fn compute_offchain_election<T: Trait>() -> Result<(), OffchainElecti
 	let current_era = <Module<T>>::current_era().unwrap_or_default();
 
 	// send it.
-	let call: <T as Trait>::Call = Call::submit_election_solution_unsigned(
+	let call = Call::submit_election_solution_unsigned(
 		winners,
 		compact,
 		score,
 		current_era,
 	).into();
 
-	T::SubmitTransaction::submit_unsigned(call)
+	SubmitTransaction::<T, Call<T>>::submit_unsigned_transaction(call)
 		.map_err(|_| OffchainElectionError::PoolSubmissionFailed)
 }
 

substrate/frame/system/src/lib.rs

@@ -1591,7 +1591,7 @@ impl<T: Trait> Lookup for ChainContext<T> {
 }
 
 #[cfg(test)]
-mod tests {
+pub(crate) mod tests {
 	use super::*;
 	use sp_std::cell::RefCell;
 	use sp_core::H256;
@@ -1602,7 +1602,7 @@ mod tests {
 		pub enum Origin for Test where system = super {}
 	}
 
-	#[derive(Clone, Eq, PartialEq)]
+	#[derive(Clone, Eq, PartialEq, Debug)]
 	pub struct Test;
 
 	parameter_types! {
@@ -1630,8 +1630,9 @@ mod tests {
 		fn on_killed_account(who: &u64) { KILLED.with(|r| r.borrow_mut().push(*who)) }
 	}
 
-	#[derive(Debug)]
-	pub struct Call {}
+	#[derive(Debug, codec::Encode, codec::Decode)]
+	pub struct Call;
+
 	impl Dispatchable for Call {
 		type Origin = ();
 		type Trait = ();
@@ -1679,7 +1680,7 @@ mod tests {
 
 	type System = Module<Test>;
 
-	const CALL: &<Test as Trait>::Call = &Call {};
+	const CALL: &<Test as Trait>::Call = &Call;
 
 	fn new_test_ext() -> sp_io::TestExternalities {
 		GenesisConfig::default().build_storage::<Test>().unwrap().into()