CkPython

Verify an RSA Signature Against the Signed Hash

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Demonstrates how to validate an RSA Signature against the hash that was signed. CkPython

import sys
import chilkat

success = False

bd = chilkat.CkBinData()

for i in range(0,101):
    bd.AppendEncoded("000102030405060708090A0B0C0D0E0F","hex")

sha256_base64 = bd.getHash("sha256","base64")
print("sha256 hash in base64 format: " + sha256_base64)

base64_rsa_sig = "AwF2BbOvL6jA5DwmMAc9n6J2Cc8PI6Rj5W079+aKJcIEtPWRzHor0Bvc3aftGM3Jbgj6SXlIC3M3RYS7UZOnfiHKFNZgbxaNT5WwsWooK42ZkC8DBZl0p7OunBUKd5SciUo+TKilioeUkriN3L1Zl9hwi3HVDVqgVo3XXskwIftSqLSFlepTLTmOWj9Y93dp8J4D9RyLtNgFQBc0WB22tyJTsuY56mLcWe1AMF3LizB9OrbwjynF2u16xWlrJdugccz795fJBUV9aQSD+8S3KeqwQhoi8RK1uhD68aGCyaSpBq0NZ8COAkn7MXaF4POxrAAt8udfHM+PRfSOptcH/w=="

# Get the public key to be used for signature verification.
pubKey = chilkat.CkPublicKey()
success = pubKey.LoadFromFile("rsaKeys/chilkat-rsa-2048.pem")
if (success == False):
    print(pubKey.lastErrorText())
    sys.exit()

rsa = chilkat.CkRsa()
success = rsa.UsePublicKey(pubKey)
if (success == False):
    print(rsa.lastErrorText())
    sys.exit()

# Verify the hash against the signature.
rsa.put_EncodingMode("base64")
success = rsa.VerifyHashENC(sha256_base64,"sha256",base64_rsa_sig)

if (success == False):
    print(rsa.lastErrorText())
    print("Signature invalid.")
else:
    print("Signature valid.")