0,0 → 1,68 |
from blockcipher import * |
from pyserpent import Serpent |
|
def new(key,mode=MODE_ECB,IV=None,counter=None,segment_size=None): |
"""Create a new cipher object |
|
Wrapper for pure python implementation pyserpent.py |
|
key = raw string containing the key |
-> when using XTS mode: the key should be a tuple containing the 2 keys needed |
mode = python_Serpent.MODE_ECB/CBC/CFB/OFB/CTR/XTS/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 |
|
EXAMPLES: |
********** |
IMPORTING: |
----------- |
>>> from CryptoPlus.Cipher import python_Serpent |
|
EXAMPLE: |
--------- |
NESSIE Test Vectors: http://www.cs.technion.ac.il/~biham/Reports/Serpent/Serpent-128-128.verified.test-vectors |
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>>> cipher = python_Serpent.new(('000102030405060708090A0B0C0D0E0F').decode('hex')) |
>>> (cipher.encrypt(('33B3DC87EDDD9B0F6A1F407D14919365').decode('hex'))).encode('hex').upper() |
'00112233445566778899AABBCCDDEEFF' |
>>> ( cipher.decrypt((_).decode('hex')) ).encode('hex').upper() |
'33B3DC87EDDD9B0F6A1F407D14919365' |
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>>> cipher = python_Serpent.new(('FDFDFDFDFDFDFDFDFDFDFDFDFDFDFDFD').decode('hex')) |
>>> (cipher.encrypt(('FDFDFDFDFDFDFDFDFDFDFDFDFDFDFDFD').decode('hex'))).encode('hex').upper() |
'81F9163BDF39B5BB2932AB91DF2A5FFC' |
>>> ( cipher.decrypt((_).decode('hex')) ).encode('hex').upper() |
'FDFDFDFDFDFDFDFDFDFDFDFDFDFDFDFD' |
|
CBC EXAMPLE: |
------------- |
>>> key = ('000102030405060708090A0B0C0D0E0F').decode('hex') |
>>> IV = ('00000000000000000000000000000000').decode('hex') |
>>> plaintext = ('33B3DC87EDDD9B0F6A1F407D14919365'*3).decode('hex') |
>>> cipher = python_Serpent.new(key,python_Serpent.MODE_CBC,IV) |
>>> ciphertext = cipher.encrypt(plaintext) |
>>> decipher = python_Serpent.new(key,python_Serpent.MODE_CBC,IV) |
>>> ( decipher.decrypt(ciphertext)).encode('hex').upper() |
'33B3DC87EDDD9B0F6A1F407D1491936533B3DC87EDDD9B0F6A1F407D1491936533B3DC87EDDD9B0F6A1F407D14919365' |
""" |
return python_Serpent(key,mode,IV,counter,segment_size) |
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class python_Serpent(BlockCipher): |
def __init__(self,key,mode,IV,counter,segment_size): |
if len(key) not in (16,24,32) and type(key) is not tuple: |
raise ValueError("Key should be 128, 192 or 256 bits") |
cipher_module = Serpent |
self.blocksize = 16 |
BlockCipher.__init__(self,key,mode,IV,counter,cipher_module,segment_size) |
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def _test(): |
import doctest |
doctest.testmod() |
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if __name__ == "__main__": |
_test() |