(CkPython) RSA Encrypt and Decrypt Credit Card Numbers

CkPython sample code to RSA public-key encrypt and decrypt credit card numbers. The RSA key is loaded from an unencrypted PKCS8 file. Chilkat provides many ways of setting the key -- loading from both encrypted and unencrypted PEM, PKCS8, DER, PVK, etc. Keys may be loaded from files or in-memory representations. (The RSA component also provides the ability to generate RSA keys.)

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import sys
import chilkat

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

rsa = chilkat.CkRsa()

key = chilkat.CkPrivateKey()

# Load an RSA private key from a file:
success = key.LoadAnyFormatFile("rsaPrivateKey.key","")
if (success != True):
    print(key.lastErrorText())
    sys.exit()

# Get the key as XML:

keyXml = key.getXml()

# We'll encrypt with the public key and decrypt with the private
# key.  (It's also possible to do the reverse.)
# Note: An RSA private key is composed of different parts internally: modulus, exponent, P, Q, etc.
# An RSA public-key is a sub-set of the private key.
# Therefore, when you have a private key, you really have
# both public and private keys.
success = rsa.ImportPublicKey(keyXml)
if (success != True):
    print(rsa.lastErrorText())
    sys.exit()

# Encrypt a VISA credit card number:
# 1234-5678-0000-9999
ccNumber = "1234567800009999"

usePrivateKey = False
rsa.put_EncodingMode("base64")
encryptedStr = rsa.encryptStringENC(ccNumber,usePrivateKey)
print("Encrypted:")
print(encryptedStr)

# Now decrypt:
rsaDecryptor = chilkat.CkRsa()

rsaDecryptor.put_EncodingMode("base64")
success = rsaDecryptor.ImportPrivateKey(keyXml)

usePrivateKey = True
decryptedStr = rsaDecryptor.decryptStringENC(encryptedStr,usePrivateKey)

print("Decrypted:")
print(decryptedStr)

# Important: RSA encryption should only be used to encrypt small amounts of data.
# It is typically used for encrypting symmetric encryption
# keys such that a symmetric encryption algorithm, such as 
# AES is then used to encrypt/decrypt bulk data