ECDSA sign/verify code: update

[nakov]

Regarding ECDSA, I found this to work for the latest release of pycoin:

https://cryptobook.nakov.com/digital-signatures/ecdsa-sign-verify-examples#ecdsa-sign-verify-using-the-secp-256-k1-curve-and-sha-3-256

from pycoin.ecdsa.secp256k1 import secp256k1_generator
import hashlib, secrets

def sha3_256Hash(msg):
hashBytes = hashlib.sha3_256(msg.encode("utf8")).digest()
print(f'msgHash={hashBytes.hex()}')
return int.from_bytes(hashBytes, byteorder="big")

def signECDSAsecp256k1(msg, privKey):
msgHash = sha3_256Hash(msg)
signature = secp256k1_generator.sign(privKey, msgHash)
return signature

def verifyECDSAsecp256k1(msg, signature, pubKey):
msgHash = sha3_256Hash(msg)
valid = secp256k1_generator.verify(pubKey, msgHash, signature)
return valid

ECDSA sign message (using the curve secp256k1 + SHA3-256)

msg = "Message for ECDSA signing"
privKey = secrets.randbelow(secp256k1_generator.order())
signature = signECDSAsecp256k1(msg, privKey)
print("Message:", msg)
print("Private key:", hex(privKey))
print("Signature: r=" + hex(signature[0]) + ", s=" + hex(signature[1]))

ECDSA verify signature (using the curve secp256k1 + SHA3-256)

pubKey = secp256k1_generator * privKey
valid = verifyECDSAsecp256k1(msg, signature, pubKey)
print("\nMessage:", msg)
print("Public key: (" + hex(pubKey[0]) + ", " + hex(pubKey[1]) + ")")
print("Signature valid?", valid)

ECDSA verify tampered signature (using the curve secp256k1 + SHA3-256)

msg = "Tampered message"
valid = verifyECDSAsecp256k1(msg, signature, pubKey)
print("\nMessage:", msg)
print("Signature (tampered msg) valid?", valid)

Cheers!

Mark von der Lieth