Sign with .pfx to create .p7s, Verify with .cer

Python example to sign a file using a .pfx and creating a .p7s file as output. It then uses a .cer file to verify the signature.

Download Chilkat Python Library

import sys
import chilkat

crypt = chilkat.CkCrypt2()

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

certStore = chilkat.CkCertStore()
success = certStore.LoadPfxFile("chilkat.pfx","myPfxPassword")
if (success != True):
    print certStore.lastErrorText()
    sys.exit()

cert = certStore.FindCertBySubjectCN("Chilkat Software, Inc.")
if (cert == None ):
    print "Failed to find certificate"
    sys.exit()

#  We can explicitly choose hash/encryption algorithms using a CSP.
csp = chilkat.CkCSP()
csp.SetProviderMicrosoftEnhanced()
csp.SetHashAlgorithm("sha-1")

#  Tell the crypt component to use this cert and this CSP.
crypt.SetSigningCert(cert)
crypt.SetCSP(csp)

#  We can sign any type of file, creating a .p7s as output:
success = crypt.CreateP7S("hamlet.xml","hamlet.p7s")
if (success == True):
    print "Signature created."
else:
    print crypt.lastErrorText()

#  Verify and restore the original file:
#  Use a cert from a .cer file (which only contains the public key)
cert2 = chilkat.CkCert()
success = cert2.LoadFromFile("chilkat.cer")
if (success != True):
    print cert2.lastErrorText()
    sys.exit()

crypt.SetVerifyCert(cert2)

success = crypt.VerifyP7S("hamlet.xml","hamlet.p7s")
if (success == True):
    print "Signature verified."
else:
    print crypt.lastErrorText()