refactor: legacy second signature support (#175)

Author: alexbarnsley

crypto/identity/private_key.py

@@ -27,6 +27,22 @@ def sign(self, message: bytes) -> bytes:
 
         return bytes([der[64]]) + der[0:64]
 
+    def sign_to_ecdsa(self, message: bytes) -> bytes:
+        """Sign a message with this private key object in ECDSA format
+
+        Args:
+            message (bytes): bytes data you want to sign
+
+        Returns:
+            bytes: signature of the signed message
+        """
+
+        message_hash = bytes.fromhex(keccak.new(data=message, digest_bits=256).hexdigest())
+
+        der = self.private_key.sign_recoverable(message_hash, hasher=None)
+
+        return der[0:64] + bytes([der[64]])
+
     def to_hex(self):
         """Returns a private key in hex format
 

crypto/transactions/builder/abstract_transaction_builder.py

@@ -47,6 +47,13 @@ def sign(self, passphrase: str):
         self.transaction.data['hash'] = self.transaction.get_id()
         return self
 
+    def legacy_second_sign(self, passphrase: str, second_passphrase: str):
+        self.sign(passphrase)
+
+        self.transaction.legacy_second_sign(PrivateKey.from_passphrase(second_passphrase))
+
+        return self
+
     def verify(self):
         return self.transaction.verify()
 

crypto/transactions/types/abstract_transaction.py

@@ -35,6 +35,15 @@ def sign(self, private_key: PrivateKey):
 
         return self
 
+    def legacy_second_sign(self, second_private_key: PrivateKey):
+        transaction_hash = TransactionUtils.to_buffer(self.data, skip_signature=True).decode()
+
+        message = bytes.fromhex(transaction_hash)
+
+        self.data['legacySecondSignature'] = second_private_key.sign_to_ecdsa(message).hex()
+
+        return self
+
     def recover_sender(self):
         signature_with_recid = self._get_signature()
         if not signature_with_recid:

crypto/utils/transaction_utils.py

@@ -30,19 +30,18 @@ def to_buffer(cls, transaction: dict, skip_signature: bool = False) -> bytes:
             fields.append(cls.to_be_array(int(transaction['v']) + (Network.get_network().chain_id() * 2 + 35)))
             fields.append(bytes.fromhex(transaction['r']))
             fields.append(bytes.fromhex(transaction['s']))
+
+            if 'legacySecondSignature' in transaction and transaction['legacySecondSignature']:
+                fields.append(bytes.fromhex(transaction['legacySecondSignature']))
         else:
             # Push chainId + 0s for r and s
             fields.append(cls.to_be_array(Network.get_network().chain_id()))
             fields.append(cls.to_be_array(0))
             fields.append(cls.to_be_array(0))
 
-        # TODO: second signature handling
-
         encoded = RlpEncoder.encode(fields)
 
-        hash_input = encoded
-
-        return hash_input.encode()
+        return encoded.encode()
 
     @classmethod
     def to_hash(cls, transaction: dict, skip_signature: bool = False) -> str:

tests/fixtures/transactions/transfer-legacy-second-signature.json

@@ -0,0 +1,19 @@
+{
+	"data": {
+		"nonce": "1",
+		"gasPrice": "5000000000",
+		"gasLimit": "21000",
+		"to": "0x6F0182a0cc707b055322CcF6d4CB6a5Aff1aEb22",
+		"value": "100000000",
+		"data": "",
+		"network": 11812,
+		"v": 0,
+		"r": "a1f79cb40a4bb409d6cebd874002ceda3ec0ccb614c1d8155f5c2f7f798135f9",
+		"s": "2d2ef517aaf6feed747385e260c206f46b2ce9d6b2a585427a111685a097bd79",
+		"legacySecondSignature": "094b33b2d10c4d48cff9a9b10f79990c9a902a762b00d2f2a4d2ddad7823b59332b2da193265068c67cefea9ca8bc84e47acec406f3300a0a10b77a56ea8c18801",
+		"senderPublicKey": "0243333347c8cbf4e3cbc7a96964181d02a2b0c854faa2fef86b4b8d92afcf473d",
+		"from": "0x1E6747BEAa5B4076a6A98D735DF8c35a70D18Bdd",
+		"hash": "a39435ec5de418e77479856d06a653efc171afe43e091472af22ee359eeb83be"
+	},
+	"serialized": "f8ad0185012a05f200825208946f0182a0cc707b055322ccf6d4cb6a5aff1aeb228405f5e10080825c6ba0a1f79cb40a4bb409d6cebd874002ceda3ec0ccb614c1d8155f5c2f7f798135f9a02d2ef517aaf6feed747385e260c206f46b2ce9d6b2a585427a111685a097bd79b841094b33b2d10c4d48cff9a9b10f79990c9a902a762b00d2f2a4d2ddad7823b59332b2da193265068c67cefea9ca8bc84e47acec406f3300a0a10b77a56ea8c18801"
+}

tests/transactions/builder/conftest.py

@@ -6,6 +6,12 @@ def passphrase():
 
     return 'found lobster oblige describe ready addict body brave live vacuum display salute lizard combine gift resemble race senior quality reunion proud tell adjust angle'
 
+@pytest.fixture
+def second_passphrase():
+    """Second Passphrase used for tests"""
+
+    return 'gold favorite math anchor detect march purpose such sausage crucial reform novel connect misery update episode invite salute barely garbage exclude winner visa cruise'
+
 @pytest.fixture
 def validator_public_key():
     """BLS Public used for validator tests"""

tests/transactions/builder/test_transfer_builder.py

@@ -28,6 +28,34 @@ def test_it_should_sign_it_with_a_passphrase(passphrase, load_transaction_fixtur
     assert builder.transaction.data['hash'] == fixture['data']['hash']
     assert builder.verify()
 
+def test_it_should_sign_with_a_legacy_second_signature(passphrase, second_passphrase, load_transaction_fixture):
+    fixture = load_transaction_fixture('transactions/transfer-legacy-second-signature')
+
+    builder = (
+        TransferBuilder
+            .new()
+            .gas_price(fixture['data']['gasPrice'])
+            .nonce(fixture['data']['nonce'])
+            .gas_limit(fixture['data']['gasLimit'])
+            .to(fixture['data']['to'])
+            .value(fixture['data']['value'])
+            .legacy_second_sign(passphrase, second_passphrase)
+    )
+
+    assert builder.transaction.data['gasPrice'] == int(fixture['data']['gasPrice'])
+    assert builder.transaction.data['gasLimit'] == int(fixture['data']['gasLimit'])
+    assert builder.transaction.data['nonce'] == fixture['data']['nonce']
+    assert builder.transaction.data['to'] == fixture['data']['to']
+    assert builder.transaction.data['value'] == int(fixture['data']['value'])
+    assert builder.transaction.data['v'] == fixture['data']['v']
+    assert builder.transaction.data['r'] == fixture['data']['r']
+    assert builder.transaction.data['s'] == fixture['data']['s']
+    assert builder.transaction.data['legacySecondSignature'] == fixture['data']['legacySecondSignature']
+
+    assert builder.transaction.serialize().hex() == fixture['serialized']
+    assert builder.transaction.data['hash'] == fixture['data']['hash']
+    assert builder.verify()
+
 def test_it_should_handle_unit_converter(passphrase, address):
     builder = (
         TransferBuilder