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-----------------------------------------------------------------------------
-- |
-- Module : Coded.Encryption.Blowfish
-- Copyright : (c) Dominic Steinitz 2003
-- License : BSD-style (see the file ReadMe.tex)
--
-- Maintainer : dominic.steinitz@blueyonder.co.uk
-- Stability : experimental
-- Portability : non-portable
--
-- Takes the Blowfish module supplied by Doug Hoyte and wraps it so it can
-- used with the standard modes.
--
-----------------------------------------------------------------------------
module Codec.Encryption.Blowfish
(
-- * Function Types
encrypt,
decrypt
) where
import Data.Bits
import Data.Word
import Data.Char
import Codec.Utils
import Codec.Encryption.BlowfishAux
-- * Basic Blowfish Encryption
-- | Basic Blowfish encryption which takes a key and a block of plaintext
-- and returns the encrypted block of ciphertext according to the standard.
-- Typical keys are Word8, Word16, Word32, Word64, Word128. See
-- <http://www.counterpane.com/vectors.txt>.
encrypt :: (Integral a) => a -> Word64 -> Word64
encrypt k p = mergeWord32 (lo,hi) where
lo = head e
hi = head $ tail e
e = bfEnc (bfMakeKey (map (chr . fromIntegral) (toOctets 256 k))) [lo',hi']
(lo',hi') = (splitZord64 p)
-- | Basic Blowfish decryption which takes a key and a block of ciphertext
-- and returns the decrypted block of plaintext.
decrypt :: (Integral a) => a -> Word64 -> Word64
decrypt k p = mergeWord32 (lo,hi) where
lo = head d
hi = head $ tail d
d = bfDec (bfMakeKey (map (chr . fromIntegral) (toOctets 256 k))) [lo',hi']
(lo',hi') = splitZord64 p
splitZord64 :: Word64 -> (Word32,Word32)
splitZord64 x = (fromIntegral (shiftR (x .&. 0xffffffff00000000) 32),
fromIntegral (x .&. 0x00000000ffffffff))
mergeWord32 :: (Word32,Word32) -> Word64
mergeWord32 (lo,hi) = shift (fromIntegral lo) 32 + fromIntegral hi
|
