src/CryptoPlus/Cipher/CAST.py

   1 from blockcipher import *
   2 import Crypto.Cipher.CAST
   3
   4 def new(key,mode=MODE_ECB,IV=None,counter=None,segment_size=None):
   5     """Create a new cipher object
   6
   7     CAST using pycrypto for algo and pycryptoplus for ciphermode
   8
   9         key = raw string containing the keys
  10         mode = python_AES.MODE_ECB/CBC/CFB/OFB/CTR/CMAC, default is ECB
  11         IV = IV as a raw string, default is "all zero" IV
  12             -> only needed for CBC mode
  13         counter = counter object (CryptoPlus.Util.util.Counter)
  14             -> only needed for CTR mode
  15         segment_size = amount of bits to use from the keystream in each chain part
  16             -> supported values: multiple of 8 between 8 and the blocksize
  17                of the cipher (only per byte access possible), default is 8
  18             -> only needed for CFB mode
  19
  20     EXAMPLES:
  21     **********
  22     IMPORTING:
  23     -----------
  24     >>> from CryptoPlus.Cipher import CAST
  25
  26     ECB example: http://www.rfc-editor.org/rfc/rfc2144.txt
  27     -------------
  28     128 bit key
  29
  30     >>> key = "0123456712345678234567893456789A".decode('hex')
  31     >>> plaintext = "0123456789ABCDEF".decode('hex')
  32     >>> cipher = CAST.new(key,CAST.MODE_ECB,)
  33     >>> cipher.encrypt(plaintext).encode('hex')
  34     '238b4fe5847e44b2'
  35
  36     40 bit key
  37     >>> from CryptoPlus.Cipher import CAST
  38     >>> key = "0123456712".decode('hex')
  39     >>> plaintext = "0123456789ABCDEF".decode('hex')
  40     >>> cipher = CAST.new(key,CAST.MODE_ECB,)
  41     >>> cipher.encrypt(plaintext).encode('hex').upper()
  42     '7AC816D16E9B302E'
  43     """
  44     return CAST(key,mode,IV,counter,segment_size)
  45
  46 class CAST(BlockCipher):
  47     def __init__(self,key,mode,IV,counter,segment_size):
  48         cipher_module = Crypto.Cipher.CAST.new
  49         self.blocksize = 8
  50         BlockCipher.__init__(self,key,mode,IV,counter,cipher_module,segment_size)
  51
  52 def _test():
  53     import doctest
  54     doctest.testmod()
  55
  56 if __name__ == "__main__":
  57     _test()