(Chilkat2-Python) Load Certificate from Smart Card by Key Usage

See more Certificates Examples

You may have a smartcard or USB token that contains only 2 certificates, one for signing, and one for authentication, and you wish to load the certificate for signing. This example demonstrates how to load the 1st certificate found on a smartcard that matches the intended key usage.

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import sys
import chilkat2

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

cert = chilkat2.Cert()

# If you know the smart card PIN, set it prior to loading from the smartcard/USB token.
cert.SmartCardPin = "12345678"

# To load a certificate matching an intended key usage, specify the type of usage as shown below.
# 
# The possible key usage keywords are:
# 
# digitalsignature
# Use when the public key is used with a digital signature mechanism to support security services other than non-repudiation, certificate signing, or CRL signing. 
# A digital signature is often used for entity authentication and data origin authentication with integrity.

# nonrepudiation
# When a digital certificate's key usage includes "nonrepudiation," it implies that the certificate and its associated private key can be used to 
# create digital signatures that provide proof of the origin and integrity of the signed data, and the signer cannot later deny having signed the data.

# Other less common usages:

# certificatesigning
# keyencipherment
# dataencipherment
# crlsigning
# secureemail
# serverauthentication
# clientauthentication
# codesigning
# timestamping

success = cert.LoadFromSmartcard("keyusage=nonrepudiation")
if (success == False):
    print(cert.LastErrorText)
    print("Certificate not loaded.")
    sys.exit()

print("Found: " + cert.SubjectDN + " serial=" + cert.SerialNumber)