Introduce sign_with method in keystore (#4925)

* Add KEY_KIND_ID to the public trait

This change is being introduced for the purpose of identifying a public
key with it's identifier and algorithm "kind".

* Use `sign_with` as implemented in BareCryptoStore

* Implement `sign_with` in sc_keystore

* Fix inconsistencies, use *_KIND_ID in sp_core testing

* Rename KeyKindId to CryptoTypeId

* Remove pair-returning functions from BareCryptoStore trait

* Define CryptoTypeId in app-crypto macros

* Add functions to get keys supported by keystore

* Fix sign_with signature to include CryptoTypePublicPair

* Add `sign_with_any` and `sign_with_all`

* Use keystore.sign_with in auth_discovery

* Rename get_supported_keys -> supported_keys

* Added headers to function docstrings

* Use chain instead of extending a temp vector

* Fixed some code formatting

* Restrict size of CryptoTypeId

This is to be able to use Encode/Decode derives and the overcome having
the size being unknown at compile-time.

* Implement sign_with in the trait itself

* Remove whitespace

* Use key_type also as a CryptoTypeId in app_crypto macros

* Rename `get_keys` to `keys` in BareCryptoStore

* Remove usage of key_pair funcs in tests

* Adjust docstring for *_CYPTO_ID constants

* Fix failures

* Simplify mapping on keys

* Remove one let

* Fixed typo

* PR feedback

* remove whitespace

* Zip keys and signatures

* Use into_iter & remove cloned

* Pass index to MissingSignature

* Use typed errors instead of strings for BareCryptoStore

* Implement Debug for trait error

* Use hashsets for better performance for supported_keys

* Make sure keys are inserted into the keystore

* Make sign_with_all return type consistent with `sign_with`

* Rename Error to BareCryptoStoreError

* Rename CRYPT_TYPE_ID -> CRYPTO_ID

* Remove unnecessary CRYPTO_ID declaration in Public trait

* Convert pub key to CryptoTypePublicPair

* Fix use

* Fix code style

* Implement From on CryptoTypePublicPair in app_crypto macros

* Change CryptoTypePublicPair to a struct

* Implement Display on CryptoTypePublicPair

* Pass CryptoTypePublicPair to MissingSignature error

* Adjust docs according to function signature

* Unify keys implementation

* Fix RPC author tests

* Fix stackoverflow

* Tabify spaces

* Pass KeyTypeId to error for easier debugging

* Fix asserts

* Use ToHex to format public key

* Use constants from sp_core

* Rename testing KeyTypeId constants

* Please compiler

* Restore KeyTypeId names

apparently, they're not only used in tests

* Use BareCryptoStoreError instead of String

* Document return value

* Fix borrow check

* Convert to hashset internally

* WIP - iter_keys

* Return raw_public_keys

* Address PR feedback

* Address PR Feedback

* Fix hexdisplay import error

* Update primitives/core/src/traits.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/client/authority-discovery/src/error.rs

@@ -16,6 +16,8 @@
 
 //! Authority discovery errors.
 
+use sp_core::crypto::CryptoTypePublicPair;
+
 /// AuthorityDiscovery Result.
 pub type Result<T> = std::result::Result<T, Error>;
 
@@ -46,6 +48,10 @@ pub enum Error {
 	EncodingDecodingScale(codec::Error),
 	/// Failed to parse a libp2p multi address.
 	ParsingMultiaddress(libp2p::core::multiaddr::Error),
+	/// Failed to sign using a specific public key
+	MissingSignature(CryptoTypePublicPair),
+	/// Failed to sign using all public keys
+	Signing,
 	/// Failed to register Prometheus metric.
 	Prometheus(prometheus_endpoint::PrometheusError),
 }

substrate/client/authority-discovery/src/lib.rs

@@ -63,7 +63,7 @@ use prost::Message;
 use sc_client_api::blockchain::HeaderBackend;
 use sc_network::{DhtEvent, ExHashT, NetworkStateInfo};
 use sp_authority_discovery::{AuthorityDiscoveryApi, AuthorityId, AuthoritySignature, AuthorityPair};
-use sp_core::crypto::{key_types, Pair};
+use sp_core::crypto::{key_types, CryptoTypePublicPair, Pair};
 use sp_core::traits::BareCryptoStorePtr;
 use sp_runtime::{traits::Block as BlockT, generic::BlockId};
 use sp_api::ProvideRuntimeApi;
@@ -283,19 +283,36 @@ where
 			.encode(&mut serialized_addresses)
 			.map_err(Error::EncodingProto)?;
 
-		for key in self.get_priv_keys_within_authority_set()?.into_iter() {
-			let signature = key.sign(&serialized_addresses);
+		let keys: Vec<CryptoTypePublicPair> = self.get_own_public_keys_within_authority_set()?
+			.into_iter()
+			.map(Into::into)
+			.collect();
 
+		let signatures = self.key_store
+			.read()
+			.sign_with_all(
+				key_types::AUTHORITY_DISCOVERY,
+				keys.clone(),
+				serialized_addresses.as_slice(),
+			)
+			.map_err(|_| Error::Signing)?;
+
+		for (sign_result, key) in signatures.iter().zip(keys) {
 			let mut signed_addresses = vec![];
+
+			// sign_with_all returns Result<Signature, Error> signature
+			// is generated for a public key that is supported.
+			// Verify that all signatures exist for all provided keys.
+			let signature = sign_result.as_ref().map_err(|_| Error::MissingSignature(key.clone()))?;
 			schema::SignedAuthorityAddresses {
 				addresses: serialized_addresses.clone(),
-				signature: signature.encode(),
+				signature: Encode::encode(&signature),
 			}
 			.encode(&mut signed_addresses)
 				.map_err(Error::EncodingProto)?;
 
 			self.network.put_value(
-				hash_authority_id(key.public().as_ref())?,
+				hash_authority_id(key.1.as_ref())?,
 				signed_addresses,
 			);
 		}
@@ -446,21 +463,6 @@ where
 		Ok(())
 	}
 
-	/// Retrieve all local authority discovery private keys that are within the current authority
-	/// set.
-	fn get_priv_keys_within_authority_set(&mut self) -> Result<Vec<AuthorityPair>> {
-		let keys = self.get_own_public_keys_within_authority_set()?
-			.into_iter()
-			.map(std::convert::Into::into)
-			.filter_map(|pub_key| {
-				self.key_store.read().sr25519_key_pair(key_types::AUTHORITY_DISCOVERY, &pub_key)
-			})
-			.map(std::convert::Into::into)
-			.collect();
-
-		Ok(keys)
-	}
-
 	/// Retrieve our public keys within the current authority set.
 	//
 	// A node might have multiple authority discovery keys within its keystore, e.g. an old one and