3DES Encryption, ECB, CBC modes

3DES encryption. The Chilkat encryption component supports Triple-DES in both ECB (Electronic Cookbook) and CBC (Cipher-Block Chaining) cipher modes.

Download Chilkat Python Library

import sys
import chilkat

crypt = chilkat.CkCrypt2()

success = crypt.UnlockComponent("Anything for 30-day trial")
if (success != True):
    print "Crypt component unlock failed"
    sys.exit()

#  Specify 3DES for the encryption algorithm:
crypt.put_CryptAlgorithm("3des")

#  CipherMode may be "ecb" or "cbc"
crypt.put_CipherMode("cbc")

#  KeyLength must be 192.  3DES is technically 168-bits;
#  the most-significant bit of each key byte is a parity bit,
#  so we must indicate a KeyLength of 192, which includes
#  the parity bits.
crypt.put_KeyLength(192)

#  The padding scheme determines the contents of the bytes
#  that are added to pad the result to a multiple of the
#  encryption algorithm's block size.  3DES has a block
#  size of 8 bytes, so encrypted output is always
#  a multiple of 8.
crypt.put_PaddingScheme(0)

#  EncodingMode specifies the encoding of the output for
#  encryption, and the input for decryption.
#  It may be "hex", "url", "base64", or "quoted-printable".
crypt.put_EncodingMode("hex")

#  An initialization vector is required if using CBC or CFB modes.
#  ECB mode does not use an IV.
#  The length of the IV is equal to the algorithm's block size.
#  It is NOT equal to the length of the key.
ivHex = "0001020304050607"
crypt.SetEncodedIV(ivHex,"hex")

#  The secret key must equal the size of the key.  For
#  3DES, the key must be 24 bytes (i.e. 192-bits).
keyHex = "000102030405060708090A0B0C0D0E0F0001020304050607"
crypt.SetEncodedKey(keyHex,"hex")

#  Encrypt a string...
#  The input string is 44 ANSI characters (i.e. 44 bytes), so
#  the output should be 48 bytes (a multiple of 8).
#  Because the output is a hex string, it should
#  be 96 characters long (2 chars per byte).
encStr = crypt.encryptStringENC("The quick brown fox jumps over the lazy dog.")
print encStr

#  Now decrypt:
decStr = crypt.decryptStringENC(encStr)
print decStr