crypton-1.0.2: Crypto/Cipher/DES.hs

-- |
-- Module      : Crypto.Cipher.DES
-- License     : BSD-style
-- Maintainer  : Vincent Hanquez <vincent@snarc.org>
-- Stability   : stable
-- Portability : good
module Crypto.Cipher.DES (
    DES,
) where

import Crypto.Cipher.DES.Primitive
import Crypto.Cipher.Types
import Crypto.Error
import Crypto.Internal.ByteArray (ByteArrayAccess)
import qualified Crypto.Internal.ByteArray as B
import Data.Memory.Endian
import Data.Word

-- | DES Context
data DES = DES Word64
    deriving (Eq)

instance Cipher DES where
    cipherName _ = "DES"
    cipherKeySize _ = KeySizeFixed 8
    cipherInit k = initDES k

instance BlockCipher DES where
    blockSize _ = 8
    ecbEncrypt (DES key) = B.mapAsWord64 (unBlock . encrypt key . Block)
    ecbDecrypt (DES key) = B.mapAsWord64 (unBlock . decrypt key . Block)

initDES :: ByteArrayAccess key => key -> CryptoFailable DES
initDES k
    | len == 8 = CryptoPassed $ DES key
    | otherwise = CryptoFailed $ CryptoError_KeySizeInvalid
  where
    len = B.length k
    key = fromBE $ B.toW64BE k 0