python_Blowfish.py

from .blockcipher import *
from .pyblowfish import Blowfish

def new(key,mode=MODE_ECB,IV=None,counter=None,segment_size=None):
    """Create a new cipher object

    Wrapper for pure python implementation pyblowfish.py

        key = raw string containing the key
        mode = Blowfish.MODE_ECB/CBC/CFB/OFB/CTR/CMAC, default is ECB
        IV = IV as a raw string, default is "all zero" IV
            -> only needed for CBC mode
        counter = counter object (CryptoPlus.Util.util.Counter)
            -> only needed for CTR mode
        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_Blowfish

    EXAMPLE: (http://www.schneier.com/code/vectors.txt)
    ----------

    >>> cipher = python_Blowfish.new(codecs.decode('0131D9619DC1376E', 'hex'))
    >>> codecs.encode(cipher.encrypt(codecs.decode('5CD54CA83DEF57DA', 'hex')), 'hex')
    b'b1b8cc0b250f09a0'
    >>> codecs.encode(cipher.decrypt(codecs.decode(_, 'hex')), 'hex')
    b'5cd54ca83def57da'

    CBC, CFB, OFB EXAMPLE: http://www.schneier.com/code/vectors.txt
    ----------------------
    >>> key = codecs.decode('0123456789ABCDEFF0E1D2C3B4A59687', 'hex')
    >>> IV = codecs.decode('FEDCBA9876543210', 'hex')
    >>> plaintext = codecs.decode('37363534333231204E6F77206973207468652074696D6520', 'hex')
    >>> cipher = python_Blowfish.new(key,python_Blowfish.MODE_CBC,IV)
    >>> ciphertext = cipher.encrypt(plaintext)
    >>> codecs.encode(ciphertext, 'hex').upper()
    b'6B77B4D63006DEE605B156E27403979358DEB9E7154616D9'


    >>> key = codecs.decode('0123456789ABCDEFF0E1D2C3B4A59687', 'hex')
    >>> iv = codecs.decode('FEDCBA9876543210', 'hex')
    >>> plaintext = codecs.decode('37363534333231204E6F77206973207468652074696D6520666F722000', 'hex')

    >>> cipher = python_Blowfish.new(key,python_Blowfish.MODE_CBC,iv)
    >>> ciphertext = cipher.encrypt(plaintext)
    >>> codecs.encode(ciphertext, 'hex').upper()
    b'6B77B4D63006DEE605B156E27403979358DEB9E7154616D9'

    >>> cipher = python_Blowfish.new(key,python_Blowfish.MODE_CFB,iv,segment_size=64)
    >>> ciphertext = cipher.encrypt(plaintext)
    >>> codecs.encode(ciphertext, 'hex').upper()
    b'E73214A2822139CAF26ECF6D2EB9E76E3DA3DE04D1517200519D57A6C3'

    >>> cipher = python_Blowfish.new(key,python_Blowfish.MODE_OFB,iv)
    >>> ciphertext = cipher.encrypt(plaintext)
    >>> codecs.encode(ciphertext, 'hex').upper()
    b'E73214A2822139CA62B343CC5B65587310DD908D0C241B2263C2CF80DA'"""
    return python_Blowfish(key,mode,IV,counter,segment_size)

class python_Blowfish(BlockCipher):
    key_error_message = "Key should be between 8 and 56 bytes (64 <-> 448 bits)"

    def __init__(self,key,mode,IV,counter,segment_size):
        cipher_module = Blowfish
        self.blocksize = 8
        BlockCipher.__init__(self,key,mode,IV,counter,cipher_module,segment_size)

    def keylen_valid(self,key):
        return 8 <= len(key) <= 56

def _test():
    import doctest
    doctest.testmod()

if __name__ == "__main__":
    _test()