(Python) RSA Signature/Verify with .key and .cer

Demonstrates how to use a .key file (private key) and digital certificate (.cer, public key) to create and verify an RSA signature.

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import sys
import chilkat

privKey = chilkat.CkPrivateKey()

#  Load the private key from an RSA .key file:
success = privKey.LoadPemFile("privateKey.key")
if (success != True):
    print privKey.lastErrorText()
    sys.exit()

#  Get the private key in XML format:
privKeyXml = privKey.getXml()

rsa = chilkat.CkRsa()

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

#  Import the private key into the RSA component:
success = rsa.ImportPrivateKey(privKeyXml)
if (success != True):
    print rsa.lastErrorText()
    sys.exit()

#  Create the signature as a hex string:
rsa.put_EncodingMode("hex")

#  If some other non-Chilkat application or web service is going to be verifying
#  the signature, it is important to match the byte-ordering.
#  The LittleEndian property may be set to True
#  for little-endian byte ordering,
#  or False  for big-endian byte ordering.
#  Microsoft apps typically use little-endian, while
#  OpenSSL and other services (such as Amazon CloudFront)
#  use big-endian.
rsa.put_LittleEndian(False)

strData = "This is the string to be signed."

#  Sign the string using the sha-1 hash algorithm.
#  Other valid choices are "md2", "sha256", "sha384",
#  "sha512", and "md5".
hexSig = rsa.signStringENC(strData,"sha-1")

print hexSig

#  Load a digital certificate from a .cer file:
cert = chilkat.CkCert()

success = cert.LoadFromFile("myCert.cer")
if (success != True):
    print cert.lastErrorText()
    sys.exit()

# pubKey is a CkPublicKey
pubKey = cert.ExportPublicKey()

#  Now verify using a separate instance of the RSA object:
rsa2 = chilkat.CkRsa()

#  Import the public key into the RSA object:
success = rsa2.ImportPublicKey(pubKey.getXml())
if (success != True):
    print rsa2.lastErrorText()
    sys.exit()

#  The signature is a hex string, so make sure the EncodingMode is correct:
rsa2.put_EncodingMode("hex")

#  Verify the signature:
success = rsa2.VerifyStringENC(strData,"sha-1",hexSig)
if (success != True):
    print rsa2.lastErrorText()
    sys.exit()

print "Success."