0,0 → 1,57 |
from blockcipher import * |
import pyDes |
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def new(key,mode=MODE_ECB,IV=None,counter=None,segment_size=None): |
"""Create a new cipher object |
|
wrapper for pure python implementation pyDes.py |
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key = raw string containing the key |
mode = python_DES.MODE_ECB/CBC/CFB/OFB/CTR/CMAC, default is ECB |
-> for every mode, except ECB and CTR, it is important to construct a seperate cipher for encryption and decryption |
IV = IV as a raw string, default is "all zero" IV |
-> needed for CBC, CFB and OFB mode |
counter = counter object (CryptoPlus.Util.util.Counter) |
-> only needed for CTR mode |
-> use a seperate counter object for the cipher and decipher: the counter is updated directly, not a copy |
see CTR example further on in the docstring |
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 |
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EXAMPLES: |
********** |
IMPORTING: |
----------- |
>>> from CryptoPlus.Cipher import python_DES |
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EXAMPLE (test vectors from NESSIE): |
----------------------------------- |
>>> cipher = python_DES.new(('7CA110454A1A6E57').decode('hex')) |
>>> ciphertext = cipher.encrypt(('01A1D6D039776742').decode('hex')) |
>>> (ciphertext).encode('hex') |
'690f5b0d9a26939b' |
>>> plaintext = cipher.decrypt(ciphertext) |
>>> (plaintext).encode('hex') |
'01a1d6d039776742' |
""" |
return python_DES(key,mode,IV,counter,segment_size) |
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class python_DES(BlockCipher): |
key_error_message = ("Key should be 64 bits") |
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def __init__(self,key,mode,IV,counter,segment_size): |
cipher_module = pyDes.des |
self.blocksize = 8 |
BlockCipher.__init__(self,key,mode,IV,counter,cipher_module,segment_size) |
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def keylen_valid(self,key): |
return len(key) == 8 |
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def _test(): |
import doctest |
doctest.testmod() |
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if __name__ == "__main__": |
_test() |