use 27-based signature

Author: alexbarnsley

crypto/utils/message.py

@@ -66,7 +66,7 @@ def sign(cls, message: Union[bytes, str], passphrase: Union[bytes, str]):
 
         transaction_signature = private_key.sign(MESSAGE_PREFIX + (str(len(message))).encode() + message)
 
-        signature_v = bytes([transaction_signature[0]]).hex()
+        signature_v = bytes([int(transaction_signature[0]) + 27]).hex()
         signature_r = transaction_signature[1:33].hex()
         signature_s = transaction_signature[33:].hex()
 
@@ -94,7 +94,7 @@ def verify(self):
         signature_s = signature[32:64]
         signature_v = signature[64]
 
-        signature = signature_r + signature_s + bytes([signature_v])
+        signature = signature_r + signature_s + bytes([signature_v - 27])
 
         public_key = PublicKey.recover(message_hash, signature)
 

tests/fixtures/message-sign.json

@@ -1,5 +1,5 @@
 {
     "message": "Hello, world!",
     "publicKey": "0243333347c8cbf4e3cbc7a96964181d02a2b0c854faa2fef86b4b8d92afcf473d",
-    "signature": "0x2bdd0c58ff8a25f456065fb731c73308a25d0a09f351f23e3c7dd3882776d33d626b0cafc0b99dd7504b24f6ecd2e036a267c8e5e005f36dcbc03b2e33fa7fc301"
+    "signature": "0x2bdd0c58ff8a25f456065fb731c73308a25d0a09f351f23e3c7dd3882776d33d626b0cafc0b99dd7504b24f6ecd2e036a267c8e5e005f36dcbc03b2e33fa7fc31c"
 }