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ARC2.py
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60 lines (52 loc) · 2.27 KB
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from __future__ import absolute_import
from .blockcipher import *
import Crypto.Cipher.ARC2
import Crypto
from pkg_resources import parse_version
def new(key,mode=MODE_ECB,IV=None,counter=None,segment_size=None,effective_keylen=None):
"""Create a new cipher object
ARC2 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
effective_keylen = how much bits to effectively use from the supplied key
-> will only be used when the pycrypto version on your system is >2.0.1
EXAMPLES:
**********
IMPORTING:
-----------
>>> from CryptoPlus.Cipher import ARC2
http://www.ietf.org/rfc/rfc2268.txt
Doctest will fail when using pycrypto 2.0.1 and older
------------------------------------
>>> key = "0000000000000000".decode('hex')
>>> plaintext = "0000000000000000".decode('hex')
>>> ek = 63
>>> cipher = ARC2.new(key,ARC2.MODE_ECB,effective_keylen=ek)
>>> cipher.encrypt(plaintext).encode('hex')
'ebb773f993278eff'
"""
return ARC2(key,mode,IV,counter,effective_keylen,segment_size)
class ARC2(BlockCipher):
def __init__(self,key,mode,IV,counter,effective_keylen,segment_size):
# pycrypto versions newer than 2.0.1 will have support for "effective_keylen"
if parse_version(Crypto.__version__) <= parse_version("2.0.1"):
cipher_module = Crypto.Cipher.ARC2.new
args = {}
else:
cipher_module = Crypto.Cipher.ARC2.new
args = {'effective_keylen':effective_keylen}
self.blocksize = 8
BlockCipher.__init__(self,key,mode,IV,counter,cipher_module,segment_size,args)
def _test():
import doctest
doctest.testmod()
if __name__ == "__main__":
_test()