(CkPython) RSA Hash Binary Data and Sign (and Verify)

Demonstrates how to sign the hash of binary data. Also demonstrates how to verify the RSA signature.

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat Python Downloads install with pip pip3 install chilkat or download... Python Module for Windows, MacOS, Linux, Alpine Linux

import sys
import chilkat

success = False

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# Load an RSA private key for signing.
privKey = chilkat.CkPrivateKey()
success = privKey.LoadEncryptedPemFile("qa_data/pem/rsa_passwd.pem","passwd")
if (success == False):
    print(privKey.lastErrorText())
    sys.exit()

rsa = chilkat.CkRsa()
rsa.UsePrivateKey(privKey)

# We have some binary data (in hex) to sign
originalData = "0102030405060708090A"
bdData = chilkat.CkBinData()
bdData.AppendEncoded(originalData,"hex")

# Hash (SHA-256) and sign the hash:
bdSignature = chilkat.CkBinData()
success = rsa.SignBd(bdData,"sha256",bdSignature)
if (success == False):
    print(rsa.lastErrorText())
    sys.exit()

# Show the RSA signature in base64
print(bdSignature.getEncoded("base64"))

# ------------------------------------------
# Get the public key from the private key
pubKey = chilkat.CkPublicKey()
privKey.ToPublicKey(pubKey)

# Verify the signature..
rsa2 = chilkat.CkRsa()
rsa2.UsePublicKey(pubKey)

bVerified = rsa2.VerifyBd(bdData,"sha256",bdSignature)
print("signature verified: " + str(bVerified))