-- | -- Module : Crypto.Cipher.DES.Serialization -- License : BSD-style -- Maintainer : Vincent Hanquez <vincent@snarc.org> -- Stability : stable -- Portability : good -- -- basic routine to convert between W64 and bytestring for DES. -- {-# LANGUAGE CPP #-} module Crypto.Cipher.DES.Serialization ( toW64 , toBS , blockify , unblockify ) where import qualified Data.ByteString as B import Crypto.Cipher.DES.Primitive (Block(..)) #ifdef ARCH_IS_LITTLE_ENDIAN import Data.Word (Word64) import Data.Byteable (withBytePtr) import qualified Data.ByteString.Internal as B (inlinePerformIO, unsafeCreate) import Foreign.Storable import Foreign.Ptr (castPtr, plusPtr, Ptr) import Data.Bits (shiftL, shiftR, (.|.), (.&.)) #else import Data.Bits (shiftL, shiftR, (.|.)) #endif #ifdef ARCH_IS_LITTLE_ENDIAN -- | convert a 8 byte bytestring big endian to a host one toW64 :: B.ByteString -> Block toW64 b = Block $ B.inlinePerformIO $ withBytePtr b $ \ptr -> (be64 `fmap` peek (castPtr ptr)) -- | convert a word64 to a bytestring in big endian format toBS :: Block -> B.ByteString toBS (Block w) = B.unsafeCreate 8 $ \ptr -> poke (castPtr ptr) (be64 w) -- | Create a strict bytestring out of DES blocks unblockify :: [Block] -> B.ByteString unblockify blocks = B.unsafeCreate (nbBlocks * 8) $ \initPtr -> pokeTo (castPtr initPtr) blocks where nbBlocks = length blocks pokeTo :: Ptr Word64 -> [Block] -> IO () pokeTo _ [] = return () pokeTo ptr (Block x:xs) = poke ptr (be64 x) >> pokeTo (ptr `plusPtr` 8) xs be64 :: Word64 -> Word64 be64 w = (w `shiftR` 56) .|. (w `shiftL` 56) .|. ((w `shiftR` 40) .&. 0xff00) .|. ((w .&. 0xff00) `shiftL` 40) .|. ((w `shiftR` 24) .&. 0xff0000) .|. ((w .&. 0xff0000) `shiftL` 24) .|. ((w `shiftR` 8) .&. 0xff000000) .|. ((w .&. 0xff000000) `shiftL` 8) #else -- | convert a 8 byte bytestring to a little endian word64 toW64 :: B.ByteString -> Block toW64 bs = Block $ case B.unpack bs of [a,b,c,d,e,f,g,h] -> shl h 0 .|. shl g 8 .|. shl f 16 .|. shl e 24 .|. shl d 32 .|. shl c 40 .|. shl b 48 .|. shl a 56 _ -> 0 where shl w n = fromIntegral w `shiftL` n -- | convert a word64 to a bytestring in little endian format toBS :: Block -> B.ByteString toBS (Block b) = B.pack $ map (shr b) [56,48,40,32,24,16,8,0] where shr w n = fromIntegral (w `shiftR` n) -- | Create a strict bytestring out of DES blocks unblockify :: [Block] -> B.ByteString unblockify = B.concat . map toBS #endif -- | create DES blocks from a strict bytestring blockify :: B.ByteString -> [Block] blockify s | B.null s = [] | otherwise = let (s1,s2) = B.splitAt 8 s in toW64 s1:blockify s2