(CkPython) RSA Sign String using Private Key of Certificate Type A3 (smart card / token)

Demonstrates RSA signing a string using the private key of a certificate type A3 (smart card, token).

Note: This is a Windows-only example.

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

import sys
import chilkat

# First get the A3 certificate that was installed on the Windows system.
certStore = chilkat.CkCertStore()

thumbprint = "12c1dd8015f3f03f7b1fa619dc24e2493ca8b4b2"

# This is specific to Windows because it is opening the Windows Current-User certificate store.
bReadOnly = True
success = certStore.OpenCurrentUserStore(bReadOnly)
if (success != True):
    print(certStore.lastErrorText())
    sys.exit()

# Find the certificate with the desired thumbprint
# (There are many ways to locate a certificate.  This example chooses to find by thumbprint.)
# cert is a CkCert
cert = certStore.FindCertBySha1Thumbprint(thumbprint)
if (certStore.get_LastMethodSuccess() != True):
    print("Failed to find the certificate.")
    sys.exit()

print("Found: " + cert.subjectCN())

rsa = chilkat.CkRsa()

# Provide the cert's private key
bUsePrivateKey = True
success = rsa.SetX509Cert(cert,bUsePrivateKey)

if (success != True):
    print(rsa.lastErrorText())
    sys.exit()

# Return the RSA signature in base64 encoded form.
rsa.put_EncodingMode("base64")

# Sign the utf-8 byte representation of the string.
rsa.put_Charset("utf-8")

# You can also choose other hash algorithms, such as SHA-1.
sigBase64 = rsa.signStringENC("text to sign","SHA-256")
if (rsa.get_LastMethodSuccess() != True):
    print(rsa.lastErrorText())
    sys.exit()

print("Base64 signature: " + sigBase64)