fix: Value Error and invalid signature validation for examples/ keys_public_ecdsa.py (#360)

* fix: invalid hex in example_load_uncompressed_ecdsa_from_hex()

Signed-off-by: Manish Dait <[email protected]>

* fix: invalid signature verification

Signed-off-by: Manish Dait <[email protected]>

* chore: resolve pylint issues

Signed-off-by: Manish Dait <[email protected]>

* chore: updated CHANGELOG.md

Signed-off-by: Manish Dait <[email protected]>

---------

Signed-off-by: Manish Dait <[email protected]>

Author: manishdait

CHANGELOG.md

@@ -51,6 +51,7 @@ This changelog is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.
 - Windows malformed path using uv run generate_proto.py using as_posix()
 - Changed README MIT license to Apache
 - deprecated CamelCase instances in /examples such as TokenId and totalSupply to snake_case
+- Invalid HEX representation and signature validation in keys_public_ecdsa.py
 
 ### Removed
 - Removed the old `/documentation` folder.

examples/keys_public_ecdsa.py

@@ -4,44 +4,46 @@
 python examples/keys_public_ecdsa.py
 
 """
-from cryptography.hazmat.primitives.asymmetric import ec
+from cryptography.hazmat.primitives.asymmetric import ec, utils
 from cryptography.hazmat.primitives import hashes
 from cryptography.exceptions import InvalidSignature
-from hiero_sdk_python.crypto.public_key import PublicKey
+from hiero_sdk_python.crypto.public_key import PublicKey, keccak256
 
 def example_load_compressed_ecdsa() -> None:
     """
     Demonstrate creating a PublicKey object from a compressed 33-byte ECDSA hex.
     """
     # A mock 33-byte compressed hex:
-    compressed_pubkey = bytes.fromhex("0281c2e57fecef82ff4f546dece3684acb6e2fe12a97af066348de81ccaf05d0a4")
-    
+    compressed_pubkey = bytes.fromhex(
+        "0281c2e57fecef82ff4f546dece3684acb6e2fe12a97af066348de81ccaf05d0a4"
+    )
+
     # 1) Construct via the specialized from_bytes_ecdsa()
     pubk_obj = PublicKey.from_bytes_ecdsa(compressed_pubkey) # or from_bytes
     print("Loaded ECDSA PublicKey (compressed) =", pubk_obj)
-    
+
     # 2) Convert it back to compressed hex
     compressed_hex = pubk_obj.to_string_ecdsa()
     print("Back to compressed hex:", compressed_hex)
-    
+
 def example_load_uncompressed_ecdsa_from_hex() -> None:
     """
     Demonstrate creating an ECDSA (secp256k1) public key from an uncompressed 65-byte hex string.
     """
     # Uncompressed secp256k1 public keys start with 0x04 and are 65 bytes total.
     uncompressed_hex = (
         "04"
-        "18a5fcc2a9af70f6248efa1a2b0cc7d6cf973f43ae6c041ff35a1a3f7d947ba6"
-        "15ba91825331ad2ce55d44469d4e874a997e3888e20e2d50322d52c365cad7f3e"
+        "0abe0517fcf06e0c160ca821aa2909945752e08169f46c984cb6b02076a3b"
+        "29513f047e5c13770101c321f332157377d2862b7c7ed14eedca3978b3b9d007659"
     )
-    
+
     # 1) Load directly from a hex string using the specialized from_string_ecdsa().
     pubk_obj = PublicKey.from_string_ecdsa(uncompressed_hex) # or from_string
     print("Loaded uncompressed ECDSA PublicKey from hex:", pubk_obj)
-    
+
     # 2) Convert to compressed raw bytes or hex:
     compressed_bytes = pubk_obj.to_bytes_ecdsa() #or to_bytes_raw
-    print("Compressed ECDSA bytes (len={}):".format(len(compressed_bytes)), compressed_bytes.hex())
+    print(f"Compressed ECDSA bytes (len={len(compressed_bytes)}): {compressed_bytes.hex()}")
 
 def example_verify_ecdsa_signature() -> None:
     """
@@ -53,11 +55,11 @@ def example_verify_ecdsa_signature() -> None:
 
     # 1) Wrap in the PublicKey class
     pubk_obj = PublicKey(public_key)
-    
+
     # 2) Sign some data
     data = b"Hello ECDSA"
-    signature = private_key.sign(data, ec.ECDSA(hashes.SHA256()))
-    
+    signature = private_key.sign(keccak256(data), ec.ECDSA(utils.Prehashed(hashes.SHA256())))
+
     # 3) Verify with pubk_obj
     try:
         pubk_obj.verify(signature, data)