| 0,0 → 1,55 |
|---|
| 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: |
| ----------- |
| >>> from CryptoPlus.Cipher import python_Twofish |
| |
| EXAMPLE: |
| ---------- |
| http://www.schneier.com/code/ecb_ival.txt -> test vector I=5 |
| |
| >>> cipher = python_Twofish.new(('019F9809DE1711858FAAC3A3BA20FBC3').decode('hex')) |
| >>> (cipher.encrypt(('6363977DE839486297E661C6C9D668EB').decode('hex'))).encode('hex').upper() |
| '816D5BD0FAE35342BF2A7412C246F752' |
| >>> ( cipher.decrypt((_).decode('hex')) ).encode('hex').upper() |
| '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() |