feat(signer): ethereum implementation

Cargo.toml

@@ -150,6 +150,7 @@ hmac = { version = "0.12.1", default-features = false }
 pbkdf2 = { version = "0.12.2", default-features = false }
 schnorrkel = { version = "0.11.4", default-features = false }
 secp256k1 = { version = "0.28.2", default-features = false }
+keccak-hash = { version = "0.10.0", default-features = false }
 secrecy = "0.8.0"
 sha2 = { version = "0.10.8", default-features = false }
 zeroize = { version = "1", default-features = false }

signer/Cargo.toml

@@ -15,7 +15,7 @@ description = "Sign extrinsics to be submitted by Subxt"
 keywords = ["parity", "subxt", "extrinsic", "signer"]
 
 [features]
-default = ["sr25519", "ecdsa", "subxt", "std", "native"]
+default = ["sr25519", "ecdsa", "eth", "subxt", "std", "native"]
 std = ["regex/std", "sp-crypto-hashing/std", "pbkdf2/std", "sha2/std", "hmac/std", "bip39/std", "schnorrkel/std", "secp256k1/std", "sp-core/std"]
 
 # Pick the signer implementation(s) you need by enabling the
@@ -24,6 +24,7 @@ std = ["regex/std", "sp-crypto-hashing/std", "pbkdf2/std", "sha2/std", "hmac/std
 # https://github.com/rust-bitcoin/rust-bitcoin/issues/930#issuecomment-1215538699
 sr25519 = ["schnorrkel"]
 ecdsa = ["secp256k1"]
+eth = ["keccak-hash", "secp256k1"]
 
 # Make the keypair algorithms here compatible with Subxt's Signer trait,
 # so that they can be used to sign transactions for compatible chains.
@@ -50,14 +51,15 @@ bip39 = { workspace = true }
 schnorrkel = { workspace = true, optional = true }
 secp256k1 = { workspace = true, optional = true, features = ["alloc", "recovery"] }
 secrecy = { workspace = true }
-
+keccak-hash = { workspace = true, optional = true }
 
 # We only pull this in to enable the JS flag for schnorrkel to use.
 getrandom = { workspace = true, optional = true }
 
 [dev-dependencies]
 sp-core = { workspace = true }
 sp-keyring = { workspace = true }
+proptest = "1.4.0"
 
 [package.metadata.cargo-machete]
 ignored = ["getrandom"]

signer/src/ecdsa.rs

@@ -160,21 +160,22 @@ impl Keypair {
 
     /// Sign some message. These bytes can be used directly in a Substrate `MultiSignature::Ecdsa(..)`.
     pub fn sign(&self, message: &[u8]) -> Signature {
-        // From sp_core::ecdsa::sign:
         let message_hash = sp_crypto_hashing::blake2_256(message);
-        // From sp_core::ecdsa::sign_prehashed:
         let wrapped = Message::from_digest_slice(&message_hash).expect("Message is 32 bytes; qed");
-        let recsig: RecoverableSignature =
-            Secp256k1::signing_only().sign_ecdsa_recoverable(&wrapped, &self.0.secret_key());
-        // From sp_core::ecdsa's `impl From<RecoverableSignature> for Signature`:
-        let (recid, sig): (_, [u8; 64]) = recsig.serialize_compact();
-        let mut signature_bytes: [u8; 65] = [0; 65];
-        signature_bytes[..64].copy_from_slice(&sig);
-        signature_bytes[64] = (recid.to_i32() & 0xFF) as u8;
-        Signature(signature_bytes)
+        Signature(sign(&self.0.secret_key(), &wrapped))
     }
 }
 
+pub(crate) fn sign(secret_key: &secp256k1::SecretKey, message: &Message) -> [u8; 65] {
+    let recsig: RecoverableSignature =
+        Secp256k1::signing_only().sign_ecdsa_recoverable(message, secret_key);
+    let (recid, sig): (_, [u8; 64]) = recsig.serialize_compact();
+    let mut signature_bytes: [u8; 65] = [0; 65];
+    signature_bytes[..64].copy_from_slice(&sig);
+    signature_bytes[64] = (recid.to_i32() & 0xFF) as u8;
+    signature_bytes
+}
+
 /// Verify that some signature for a message was created by the owner of the [`PublicKey`].
 ///
 /// ```rust