| 0,0 → 1,57 |
|---|
| from blockcipher import * |
| import pyDes |
| |
| 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 |
| |
| 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 |
| |
| EXAMPLES: |
| ********** |
| IMPORTING: |
| ----------- |
| >>> from CryptoPlus.Cipher import python_DES |
| |
| 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) |
| |
| class python_DES(BlockCipher): |
| key_error_message = ("Key should be 64 bits") |
| |
| 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) |
| |
| def keylen_valid(self,key): |
| return len(key) == 8 |
| |
| def _test(): |
| import doctest |
| doctest.testmod() |
| |
| if __name__ == "__main__": |
| _test() |