(CkPython) RSA Sign Binary Data and Verify (Recover the Original Data)

Demonstrates how to RSA sign binary data and then verify/recover the original data.

Note: This example uses methods introduced in Chilkat v9.5.0.77.

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

import sys
import chilkat

# 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 != True):
    print(privKey.lastErrorText())
    sys.exit()

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

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

# If successful, the contents of bd are replaced with the RSA signature.
success = rsa.OpenSslSignBd(bd)
if (success != True):
    print(rsa.lastErrorText())
    sys.exit()

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

# ------------------------------------------
# Get the public key from the private key
# pubKey is a CkPublicKey
pubKey = privKey.GetPublicKey()

# Verify the signature and extract the original data.
rsa2 = chilkat.CkRsa()
rsa2.ImportPublicKeyObj(pubKey)

bVerified = rsa2.OpenSslVerifyBd(bd)
print("signature verified: " + str(bVerified))

# Show the original data:
print("original data: " + bd.getEncoded("hex"))