Make BEEFY client keystore generic over BEEFY AuthorityId type (#2258)

This is the significant step to make BEEFY client able to handle both
ECDSA and (ECDSA, BLS) type signature. The idea is having BEEFY Client
generic on crypto types makes migration to new types smoother.

This makes the BEEFY Keystore generic over AuthorityId and extends its
tests to cover the case when the AuthorityId is of type (ECDSA,
BLS12-377)

---------

Co-authored-by: Davide Galassi <davxy@datawok.net>
Co-authored-by: Robert Hambrock <roberthambrock@gmail.com>

substrate/primitives/consensus/beefy/src/lib.rs

@@ -32,20 +32,22 @@
 //! while GRANDPA uses `ed25519`.
 
 mod commitment;
-pub mod mmr;
 mod payload;
-#[cfg(feature = "std")]
-mod test_utils;
+
+pub mod mmr;
 pub mod witness;
 
+/// Test utilities
+#[cfg(feature = "std")]
+pub mod test_utils;
+
 pub use commitment::{Commitment, SignedCommitment, VersionedFinalityProof};
 pub use payload::{known_payloads, BeefyPayloadId, Payload, PayloadProvider};
-#[cfg(feature = "std")]
-pub use test_utils::*;
 
 use codec::{Codec, Decode, Encode};
+use core::fmt::{Debug, Display};
 use scale_info::TypeInfo;
-use sp_application_crypto::RuntimeAppPublic;
+use sp_application_crypto::{AppCrypto, AppPublic, ByteArray, RuntimeAppPublic};
 use sp_core::H256;
 use sp_runtime::traits::{Hash, Keccak256, NumberFor};
 use sp_std::prelude::*;
@@ -63,6 +65,25 @@ pub trait BeefyAuthorityId<MsgHash: Hash>: RuntimeAppPublic {
 	fn verify(&self, signature: &<Self as RuntimeAppPublic>::Signature, msg: &[u8]) -> bool;
 }
 
+/// Hasher used for BEEFY signatures.
+pub type BeefySignatureHasher = sp_runtime::traits::Keccak256;
+
+/// A trait bound which lists all traits which are required to be implemented by
+/// a BEEFY AuthorityId type in order to be able to be used in BEEFY Keystore
+pub trait AuthorityIdBound:
+	Codec
+	+ Debug
+	+ Clone
+	+ AsRef<[u8]>
+	+ ByteArray
+	+ AppPublic
+	+ AppCrypto
+	+ RuntimeAppPublic
+	+ Display
+	+ BeefyAuthorityId<BeefySignatureHasher>
+{
+}
+
 /// BEEFY cryptographic types for ECDSA crypto
 ///
 /// This module basically introduces four crypto types:
@@ -74,7 +95,7 @@ pub trait BeefyAuthorityId<MsgHash: Hash>: RuntimeAppPublic {
 /// Your code should use the above types as concrete types for all crypto related
 /// functionality.
 pub mod ecdsa_crypto {
-	use super::{BeefyAuthorityId, Hash, RuntimeAppPublic, KEY_TYPE};
+	use super::{AuthorityIdBound, BeefyAuthorityId, Hash, RuntimeAppPublic, KEY_TYPE};
 	use sp_application_crypto::{app_crypto, ecdsa};
 	use sp_core::crypto::Wraps;
 
@@ -101,6 +122,7 @@ pub mod ecdsa_crypto {
 			}
 		}
 	}
+	impl AuthorityIdBound for AuthorityId {}
 }
 
 /// BEEFY cryptographic types for BLS crypto
@@ -116,7 +138,7 @@ pub mod ecdsa_crypto {
 
 #[cfg(feature = "bls-experimental")]
 pub mod bls_crypto {
-	use super::{BeefyAuthorityId, Hash, RuntimeAppPublic, KEY_TYPE};
+	use super::{AuthorityIdBound, BeefyAuthorityId, Hash, RuntimeAppPublic, KEY_TYPE};
 	use sp_application_crypto::{app_crypto, bls377};
 	use sp_core::{bls377::Pair as BlsPair, crypto::Wraps, Pair as _};
 
@@ -134,13 +156,14 @@ pub mod bls_crypto {
 	{
 		fn verify(&self, signature: &<Self as RuntimeAppPublic>::Signature, msg: &[u8]) -> bool {
 			// `w3f-bls` library uses IETF hashing standard and as such does not expose
-			// a choice of hash to field function.
+			// a choice of hash-to-field function.
 			// We are directly calling into the library to avoid introducing new host call.
 			// and because BeefyAuthorityId::verify is being called in the runtime so we don't have
 
 			BlsPair::verify(signature.as_inner_ref(), msg, self.as_inner_ref())
 		}
 	}
+	impl AuthorityIdBound for AuthorityId {}
 }
 
 /// BEEFY cryptographic types for (ECDSA,BLS) crypto pair
@@ -155,7 +178,7 @@ pub mod bls_crypto {
 /// functionality.
 #[cfg(feature = "bls-experimental")]
 pub mod ecdsa_bls_crypto {
-	use super::{BeefyAuthorityId, Hash, RuntimeAppPublic, KEY_TYPE};
+	use super::{AuthorityIdBound, BeefyAuthorityId, Hash, RuntimeAppPublic, KEY_TYPE};
 	use sp_application_crypto::{app_crypto, ecdsa_bls377};
 	use sp_core::{crypto::Wraps, ecdsa_bls377::Pair as EcdsaBlsPair};
 
@@ -187,6 +210,8 @@ pub mod ecdsa_bls_crypto {
 			)
 		}
 	}
+
+	impl AuthorityIdBound for AuthorityId {}
 }
 
 /// The `ConsensusEngineId` of BEEFY.