Chilkat2-Python

About RSA Public/Private Keys

See more RSA Examples

This example provides some additional information for understanding public/private key pairs. In demonstrates how a private key is a superset of the public key. A public key contains the modulus and exponent. The matching private key also contains the modulus and exponent, but also contains the additional private key parts. Chilkat2-Python

import sys
import chilkat2

success = False

cert = chilkat2.Cert()

# Load a digital certificate.
success = cert.LoadFromFile("digitalCert.cer")
if (success == False):
    print(cert.LastErrorText)
    sys.exit()

# A .cer file does not contain the private key.  It should contain
# the public key...
pubKey = chilkat2.PublicKey()
cert.GetPublicKey(pubKey)

# Let's have a look at it (in XML format).
print("Public Key from Certificate:")
print(pubKey.GetXml())

# An RSA public key consists of a modulus and exponent.

# An RSA private key includes both the modulus and exponent,
# as well as other "big" numbers: P, Q, D, etc.

# Let's load an RSA private key from a DER-encoded file:
privKey = chilkat2.PrivateKey()

success = privKey.LoadAnyFormatFile("PrivateKey.key","")
if (success != True):
    print(privKey.LastErrorText)
    sys.exit()

# If this private key is the matching half to the public key from
# the certificate, then the modulus and exponent should
# be identical.  (Thus, a "private key" really contains both the public part as well as the private parts...).
print("Private Key from DER:")
print(privKey.GetXml())