forked from doegox/python-cryptoplus
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathpython_Twofish.py
More file actions
56 lines (47 loc) · 2.3 KB
/
Copy pathpython_Twofish.py
File metadata and controls
56 lines (47 loc) · 2.3 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
from .blockcipher import *
from .pytwofish import Twofish
def new(key,mode=MODE_ECB,IV=None,counter=None,segment_size=None):
"""Create a new cipher object
Wrapper for pure python implementation pytwofish.py
key = raw string containing the key
-> when using XTS mode: the key should be a tuple containing the 2 keys needed
mode = python_Twofish.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
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:
-----------
>>> import codecs
>>> from CryptoPlus.Cipher import python_Twofish
EXAMPLE:
----------
http://www.schneier.com/code/ecb_ival.txt -> test vector I=5
>>> cipher = python_Twofish.new(codecs.decode('019F9809DE1711858FAAC3A3BA20FBC3', 'hex'))
>>> codecs.encode(cipher.encrypt(codecs.decode('6363977DE839486297E661C6C9D668EB', 'hex')), 'hex').upper()
b'816D5BD0FAE35342BF2A7412C246F752'
>>> codecs.encode(cipher.decrypt(codecs.decode(_, 'hex')), 'hex').upper()
b'6363977DE839486297E661C6C9D668EB'
"""
return python_Twofish(key,mode,IV,counter,segment_size)
class python_Twofish(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 = Twofish
self.blocksize = 16
BlockCipher.__init__(self,key,mode,IV,counter,cipher_module,segment_size)
def _test():
import doctest
doctest.testmod()
if __name__ == "__main__":
_test()