Use Certificate and Private Key PEM Files to Create a Digital Signature

Demonstrates how to load a digital certificate from a PEM file, load it's corresponding private key from a PEM file, save the private key to a key container (if necessary), link the certificate to the key container, and use it to create a digital signature.

 Chilkat Python Module Downloads for Windows, Linux, and MAC OS X

import sys
import chilkat

cert = chilkat.CkCert()

#  Load the cert from a PEM file;
cert.LoadFromFile("cert.pem")

pkey = chilkat.CkPrivateKey()

#  Load the private key from an RSA PEM file:
pkey.LoadPemFile("pkey_rsa.pem")

success = cert.SetPrivateKey(pkey)
if (success != True):
    print cert.lastErrorText()
    sys.exit()

#  Use Chilkat Crypt (a non-freeware component) to create
#  a digital signature using the certificate w/ private key:
crypt = chilkat.CkCrypt2()

#  Any string argument automatically begins the 30-day trial.
success = crypt.UnlockComponent("30-day trial")
if (success != True):
    print crypt.lastErrorText()
    sys.exit()

#  Tell the crypt component to use this cert.
crypt.SetSigningCert(cert)

#  A PKCS7 signature for any type of file content can be created:
success = crypt.CreateP7S("license.rtf","license.p7s")
if (success == False):
    print crypt.lastErrorText()
    sys.exit()

print crypt.lastErrorText()

#  Verify and restore the original file:
crypt.SetVerifyCert(cert)

success = crypt.VerifyP7S("license.rtf","license.p7s")
if (success == False):
    print crypt.lastErrorText()
    sys.exit()

print "Success!"