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CAST.py
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58 lines (48 loc) · 1.91 KB
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from __future__ import absolute_import
from .blockcipher import *
import Crypto.Cipher.CAST
def new(key,mode=MODE_ECB,IV=None,counter=None,segment_size=None):
"""Create a new cipher object
CAST using pycrypto for algo and pycryptoplus for ciphermode
key = raw string containing the keys
mode = python_AES.MODE_ECB/CBC/CFB/OFB/CTR/CMAC, default is ECB
IV = IV as a raw string, default is "all zero" IV
-> only needed for CBC mode
counter = counter object (CryptoPlus.Util.util.Counter)
-> only needed for CTR mode
segment_size = amount of bits to use from the keystream in each chain part
-> supported values: multiple of 8 between 8 and the blocksize
of the cipher (only per byte access possible), default is 8
-> only needed for CFB mode
EXAMPLES:
**********
IMPORTING:
-----------
>>> from CryptoPlus.Cipher import CAST
ECB example: http://www.rfc-editor.org/rfc/rfc2144.txt
-------------
128 bit key
>>> key = "0123456712345678234567893456789A".decode('hex')
>>> plaintext = "0123456789ABCDEF".decode('hex')
>>> cipher = CAST.new(key,CAST.MODE_ECB,)
>>> cipher.encrypt(plaintext).encode('hex')
'238b4fe5847e44b2'
40 bit key
>>> from CryptoPlus.Cipher import CAST
>>> key = "0123456712".decode('hex')
>>> plaintext = "0123456789ABCDEF".decode('hex')
>>> cipher = CAST.new(key,CAST.MODE_ECB,)
>>> cipher.encrypt(plaintext).encode('hex').upper()
'7AC816D16E9B302E'
"""
return CAST(key,mode,IV,counter,segment_size)
class CAST(BlockCipher):
def __init__(self,key,mode,IV,counter,segment_size):
cipher_module = Crypto.Cipher.CAST.new
self.blocksize = 8
BlockCipher.__init__(self,key,mode,IV,counter,cipher_module,segment_size)
def _test():
import doctest
doctest.testmod()
if __name__ == "__main__":
_test()