feat: add sign_bytes method to generate data that needs to be signed (#38)

Author: b00f

examples/example_get_node_info.py

@@ -10,7 +10,7 @@ def main() -> None:
     # Creating a stub from channel
     stub = NetworkStub(channel)
 
-    # Initialize a request and call get consensus info method
+    # Initialize a request and call get node info method
     req = GetNodeInfoRequest()
     res = stub.GetNodeInfo(req)
 

examples/example_multisig.py

@@ -1,5 +1,6 @@
 from pactus.crypto.bls.signature import Signature
 
+
 def main() -> None:
     sig1 = Signature.from_string(
         "a628a8709fe00366d7150244447cc43e8637d76a20674b006b00f7a61109dab53ba5f1f66cd07219fd1e4a6bc7299d2d"

examples/example_transfer_transaction_bls.py

@@ -22,7 +22,7 @@ def main() -> None:
     tx = Transaction.create_transfer_tx(lock_time, sender, receiver, amount, fee, memo)
     signed_tx = tx.sign(sec)
 
-    print(f"Signed transaction hex: {signed_tx}")
+    print(f"Signed transaction hex: {signed_tx.hex()}")
 
 
 if __name__ == "__main__":

examples/example_transfer_transaction_ed25519.py

@@ -22,7 +22,7 @@ def main() -> None:
     tx = Transaction.create_transfer_tx(lock_time, sender, receiver, amount, fee, memo)
     signed_tx = tx.sign(sec)
 
-    print(f"Signed transaction hex: {signed_tx}")
+    print(f"Signed transaction hex: {signed_tx.hex()}")
 
 
 if __name__ == "__main__":

pactus/transaction/transaction.py

@@ -79,7 +79,13 @@ def create_withdraw_tx(
         return cls(lock_time, fee, memo, payload)
 
     def _get_unsigned_bytes(self, buf: bytes) -> bytes:
-        """Get unsigned bytes of the transaction, including the payload."""
+        """
+        Generate the unsigned representation of the transaction,
+        including flags and payload.
+
+        This method appends various transaction components to the buffer
+        in a specific order, ensuring correct serialization.
+        """
         encoding.append_uint8(buf, self.flags)
         encoding.append_uint8(buf, self.version)
         encoding.append_uint32(buf, self.lock_time)
@@ -90,17 +96,37 @@ def _get_unsigned_bytes(self, buf: bytes) -> bytes:
 
         return buf
 
-    def sign(self, private_key: PrivateKey) -> str:
-        """Make a raw transaction, sign it and return the signed bytes."""
+    def sign_bytes(self) -> bytes:
+        """
+        Generate the transaction data that needs to be signed.
+
+        The signature should be computed over this data, excluding the
+        transaction flags, which are removed before returning.
+        """
+        buf = bytearray()
+        sign_bytes = self._get_unsigned_bytes(buf)
+
+        return sign_bytes[1:]  # flags is not part of the sign bytes.
+
+    def sign(self, private_key: PrivateKey) -> bytes:
+        """
+        Generate the signed representation of the transaction,
+        including the flags, payload, and cryptographic signature.
+
+        This method first generates the data needs to be signed,
+        signs it using the provided private key, and then appends
+        both the signature and the corresponding public key to ensure
+        verifiability.
+        """
         buf = bytearray()
 
         sign_bytes = self._get_unsigned_bytes(buf)
         sig = private_key.sign(
             bytes(sign_bytes[1:]),
-        )  # flags is not part of the sign bytes.
+        )
         pub = private_key.public_key()
 
         encoding.append_fixed_bytes(buf, sig.raw_bytes())
         encoding.append_fixed_bytes(buf, pub.raw_bytes())
 
-        return buf.hex()
+        return buf

tests/test_transaction.py

@@ -20,9 +20,9 @@ def test_sign_transfer(self):
         tx = Transaction.create_transfer_tx(
             lock_time, sender, receiver, amount, fee, memo
         )
-        signed_data = tx.sign(prv)
 
-        expected_data = (
+        signed_data = tx.sign(prv)
+        expected_signed_data = (
             "00"  # Flags
             "01"  # Version
             "56341200"  # LockTime
@@ -36,9 +36,21 @@ def test_sign_transfer(self):
             + "af0f74917f5065af94727ae9541b0ddcfb5b828a9e016b02498f477ed37fb44d5d882495afb6fd4f9773e4ea9deee436"  # Public Key
             + "030c4d61c6e3a1151585e1d838cae1444a438d089ce77e10c492a55f6908125c5be9b236a246e4082d08de564e111e65"
         )
-
         self.maxDiff = None
-        self.assertEqual(expected_data, signed_data)
+        self.assertEqual(expected_signed_data, signed_data.hex())
+
+        sign_bytes = tx.sign_bytes()
+        expected_sign_bytes = (
+            "01"  # Version
+            "56341200"  # LockTime
+            "c0843d"  # Fee
+            "0474657374"  # Memo
+            "01"  # PayloadType
+            + "02a195d7fecba4c636832f1db0cd0ea14db6db8c71"  # Sender
+            + "025e81869376b54f8a360f48930ea741e3b8771db2"  # Receiver
+            + "8094ebdc03"  # Amount
+        )
+        self.assertEqual(expected_sign_bytes, sign_bytes.hex())
 
 
 if __name__ == "__main__":