(CkPython) DKIM Signature using Windows Current User Certificate Store

This is a Windows-specific example to load a certificate from the Current User (registry-based) certificate store, and then use the certificate's associated private key for a DKIM signature.

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import sys
import chilkat

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

cert = chilkat.CkCert()

# The LoadByCommonName method searches the Windows Local Machine and Current User 
# registry-based certificate stores for a certificate having the common name specified. 
# If found, the certificate is loaded and ready for use.
success = cert.LoadByCommonName("My Certificate ABC")
if (success != True):
    print(cert.lastErrorText())
    sys.exit()

# The certificate must have an associated private key installed, and it must be a
# private key that has been marked "exportable" when it was originally installed.
if (not cert.HasPrivateKey()):
    print("This certificate does not have a private key available.")
    sys.exit()

# privKey is a CkPrivateKey
privKey = cert.ExportPrivateKey()
if (cert.get_LastMethodSuccess() == False):
    print(cert.lastErrorText())
    sys.exit()

dkim = chilkat.CkDkim()

# Load the private key into the DKIM object:
success = dkim.LoadDkimPk(privKey.getPkcs8Pem(),"")
if (success != True):
    print(dkim.lastErrorText())
    sys.exit()

# The private key has been loaded into the DKIM object.  See the other DKIM
# examples for guidance on how to create a DKIM signature...