src/CryptoPlus/Cipher/ARC2.py

   1 from blockcipher import *
   2 import Crypto.Cipher.ARC2
   3 import Crypto
   4 from pkg_resources import parse_version
   5
   6 def new(key,mode=MODE_ECB,IV=None,counter=None,segment_size=None,effective_keylen=None):
   7     """Create a new cipher object
   8
   9     ARC2 using pycrypto for algo and pycryptoplus for ciphermode
  10
  11         key = raw string containing the keys
  12         mode = python_AES.MODE_ECB/CBC/CFB/OFB/CTR/CMAC, default is ECB
  13         IV = IV as a raw string, default is "all zero" IV
  14             -> only needed for CBC mode
  15         counter = counter object (CryptoPlus.Util.util.Counter)
  16             -> only needed for CTR mode
  17         segment_size = amount of bits to use from the keystream in each chain part
  18             -> supported values: multiple of 8 between 8 and the blocksize
  19                of the cipher (only per byte access possible), default is 8
  20             -> only needed for CFB mode
  21         effective_keylen = how much bits to effectively use from the supplied key
  22             -> will only be used when the pycrypto version on your system is >2.0.1
  23
  24     EXAMPLES:
  25     **********
  26     IMPORTING:
  27     -----------
  28     >>> from CryptoPlus.Cipher import ARC2
  29
  30     http://www.ietf.org/rfc/rfc2268.txt
  31     Doctest will fail when using pycrypto 2.0.1 and older
  32     ------------------------------------
  33     >>> key = "0000000000000000".decode('hex')
  34     >>> plaintext = "0000000000000000".decode('hex')
  35     >>> ek = 63
  36     >>> cipher = ARC2.new(key,ARC2.MODE_ECB,effective_keylen=ek)
  37     >>> cipher.encrypt(plaintext).encode('hex')
  38     'ebb773f993278eff'
  39     """
  40     return ARC2(key,mode,IV,counter,effective_keylen,segment_size)
  41
  42 class ARC2(BlockCipher):
  43     def __init__(self,key,mode,IV,counter,effective_keylen,segment_size):
  44         # pycrypto versions newer than 2.0.1 will have support for "effective_keylen"
  45         if parse_version(Crypto.__version__) <= parse_version("2.0.1"):
  46             cipher_module = Crypto.Cipher.ARC2.new
  47             args = {}
  48         else:
  49             cipher_module = Crypto.Cipher.ARC2.new
  50             args = {'effective_keylen':effective_keylen}
  51         self.blocksize = 8
  52         BlockCipher.__init__(self,key,mode,IV,counter,cipher_module,segment_size,args)
  53
  54 def _test():
  55     import doctest
  56     doctest.testmod()
  57
  58 if __name__ == "__main__":
  59     _test()