-- | -- Module : Crypto.Store.Cipher.RC2.Primitive -- License : BSD-style -- Maintainer : Olivier Chéron -- Stability : stable -- Portability : good -- {-# LANGUAGE Rank2Types #-} module Crypto.Store.Cipher.RC2.Primitive ( Key , buildKey , encrypt , decrypt ) where import Basement.Block import Basement.Compat.IsList import Basement.Endianness import Basement.Types.OffsetSize import Control.Monad (forM_) import Data.Bits import Data.ByteArray (ByteArrayAccess) import qualified Data.ByteArray as B import Data.Word import Foreign.Storable -- | Expanded RC2 key newtype Key = Key (Block Word16) -- [ K[0], K[1], ..., K[63] ] data Q = Q {-# UNPACK #-} !Word16 {-# UNPACK #-} !Word16 {-# UNPACK #-} !Word16 {-# UNPACK #-} !Word16 -- Utilities decomp64 :: Word64 -> Q decomp64 x = let f = unBE . toBE . fromIntegral a = f (x `shiftR` 48) b = f (x `shiftR` 32) c = f (x `shiftR` 16) d = f x in Q a b c d comp64 :: Q -> Word64 comp64 (Q a b c d) = (f a `shiftL` 48) .|. (f b `shiftL` 32) .|. (f c `shiftL` 16) .|. f d where f = fromIntegral . unBE . toBE getR :: Q -> Word8 -> Word16 getR (Q a b c d) i = case i .&. 3 of 0 -> a 1 -> b 2 -> c _ -> d {-# INLINE getR #-} setR :: Q -> Word8 -> Word16 -> Q setR (Q a b c d) i x = case i .&. 3 of 0 -> Q x b c d 1 -> Q a x c d 2 -> Q a b x d _ -> Q a b c x {-# INLINE setR #-} rol :: Word8 -> Word16 -> Word16 rol i = case i .&. 3 of 0 -> flip rotateL 1 1 -> flip rotateL 2 2 -> flip rotateL 3 _ -> flip rotateL 5 {-# INLINE rol #-} ror :: Word8 -> Word16 -> Word16 ror i = case i .&. 3 of 0 -> flip rotateR 1 1 -> flip rotateR 2 2 -> flip rotateR 3 _ -> flip rotateR 5 {-# INLINE ror #-} f5 :: (a -> a) -> a -> a f5 f = f . f . f . f . f f6 :: (a -> a) -> a -> a f6 f = f . f . f . f . f . f -- Encryption -- | Encrypts a block using the specified key encrypt :: Key -> Word64 -> Word64 encrypt k = comp64 . enc k . decomp64 enc :: Key -> Q -> Q enc k r = fst $ f5 (mixingRound k) $ mashingRound k $ f6 (mixingRound k) $ mashingRound k $ f5 (mixingRound k) (r, 0) -- Decryption -- | Decrypts a block using the specified key decrypt :: Key -> Word64 -> Word64 decrypt k = comp64 . dec k . decomp64 dec :: Key -> Q -> Q dec k r = fst $ f5 (rmixingRound k) $ rmashingRound k $ f6 (rmixingRound k) $ rmashingRound k $ f5 (rmixingRound k) (r, 63) -- Encryptiong rounds mixUp :: Key -> Word8 -> (Q, Int) -> (Q, Int) mixUp k i input@(r, j) = seq r' $ seq j' (r', j') where j' = j + 1 r' = setR r i (rol i (ri + gmix k i input)) ri = getR r i {-# INLINE mixUp #-} mixingRound :: Key -> (Q, Int) -> (Q, Int) mixingRound k = mixUp k 3 . mixUp k 2 . mixUp k 1 . mixUp k 0 mash :: Key -> Word8 -> (Q, Int) -> (Q, Int) mash = gmash (+) {-# INLINE mash #-} mashingRound :: Key -> (Q, Int) -> (Q, Int) mashingRound k = mash k 3 . mash k 2 . mash k 1 . mash k 0 -- Decryption rounds rmixUp :: Key -> Word8 -> (Q, Int) -> (Q, Int) rmixUp k i input@(r, j) = seq r' $ seq j' (r', j') where j' = j - 1 r' = setR r i (ri - gmix k i input) ri = ror i (getR r i) {-# INLINE rmixUp #-} rmixingRound :: Key -> (Q, Int) -> (Q, Int) rmixingRound k = rmixUp k 0 . rmixUp k 1 . rmixUp k 2 . rmixUp k 3 rmash :: Key -> Word8 -> (Q, Int) -> (Q, Int) rmash = gmash (-) {-# INLINE rmash #-} rmashingRound :: Key -> (Q, Int) -> (Q, Int) rmashingRound k = rmash k 0 . rmash k 1 . rmash k 2 . rmash k 3 -- Generic rounds gmix :: Key -> Word8 -> (Q, Int) -> Word16 gmix (Key k) i (r, j) = kj + (ri1 .&. ri2) + (complement ri1 .&. ri3) where ri1 = getR r (i - 1) ri2 = getR r (i - 2) ri3 = getR r (i - 3) kj = unsafeIndex k (Offset j) {-# INLINE gmix #-} gmash :: (Word16 -> Word16 -> Word16) -> Key -> Word8 -> (Q, Int) -> (Q, Int) gmash op (Key k) i (r, j) = seq r' $ seq j (r', j) where r' = setR r i (ri `op` kp) ri = getR r i ri1 = getR r (i - 1) kp = unsafeIndex k $ Offset (fromIntegral ri1 .&. 63) {-# INLINE gmash #-} -- Key expansion -- | Perform key expansion buildKey :: ByteArrayAccess key => Int -- ^ Effective key length in bits -> key -- ^ Input key between 1 and 128 bytes -> Key -- ^ Expanded key buildKey t1 key = Key $ doCast $ B.allocAndFreeze 128 $ \p -> do B.copyByteArrayToPtr key p forM_ [t .. 127] $ \i -> do pos <- (+) <$> peekElemOff p (i - 1) <*> peekElemOff p (i - t) let b = unsafeIndex piTable (fromIntegral pos) pokeElemOff p i b pos' <- (.&. tm) <$> peekElemOff p (128 - t8) let b' = unsafeIndex piTable (fromIntegral pos') pokeElemOff p (128 - t8) b' forM_ (Prelude.reverse [0 .. 127 - t8]) $ \i -> do pos <- xor <$> peekElemOff p (i + 1) <*> peekElemOff p (i + t8) let b = unsafeIndex piTable (fromIntegral pos) pokeElemOff p i b where t = B.length key t8 = (t1 + 7) `div` 8 tm | t1 == 8 * t8 = 255 | otherwise = 255 `mod` shiftL 1 (8 + t1 - 8 * t8) doCast :: Block Word8 -> Block Word16 doCast = Basement.Block.map fromLE . cast -- PITABLE piTable :: Block Word8 piTable = fromList [ 0xd9, 0x78, 0xf9, 0xc4, 0x19, 0xdd, 0xb5, 0xed, 0x28, 0xe9, 0xfd, 0x79, 0x4a, 0xa0, 0xd8, 0x9d , 0xc6, 0x7e, 0x37, 0x83, 0x2b, 0x76, 0x53, 0x8e, 0x62, 0x4c, 0x64, 0x88, 0x44, 0x8b, 0xfb, 0xa2 , 0x17, 0x9a, 0x59, 0xf5, 0x87, 0xb3, 0x4f, 0x13, 0x61, 0x45, 0x6d, 0x8d, 0x09, 0x81, 0x7d, 0x32 , 0xbd, 0x8f, 0x40, 0xeb, 0x86, 0xb7, 0x7b, 0x0b, 0xf0, 0x95, 0x21, 0x22, 0x5c, 0x6b, 0x4e, 0x82 , 0x54, 0xd6, 0x65, 0x93, 0xce, 0x60, 0xb2, 0x1c, 0x73, 0x56, 0xc0, 0x14, 0xa7, 0x8c, 0xf1, 0xdc , 0x12, 0x75, 0xca, 0x1f, 0x3b, 0xbe, 0xe4, 0xd1, 0x42, 0x3d, 0xd4, 0x30, 0xa3, 0x3c, 0xb6, 0x26 , 0x6f, 0xbf, 0x0e, 0xda, 0x46, 0x69, 0x07, 0x57, 0x27, 0xf2, 0x1d, 0x9b, 0xbc, 0x94, 0x43, 0x03 , 0xf8, 0x11, 0xc7, 0xf6, 0x90, 0xef, 0x3e, 0xe7, 0x06, 0xc3, 0xd5, 0x2f, 0xc8, 0x66, 0x1e, 0xd7 , 0x08, 0xe8, 0xea, 0xde, 0x80, 0x52, 0xee, 0xf7, 0x84, 0xaa, 0x72, 0xac, 0x35, 0x4d, 0x6a, 0x2a , 0x96, 0x1a, 0xd2, 0x71, 0x5a, 0x15, 0x49, 0x74, 0x4b, 0x9f, 0xd0, 0x5e, 0x04, 0x18, 0xa4, 0xec , 0xc2, 0xe0, 0x41, 0x6e, 0x0f, 0x51, 0xcb, 0xcc, 0x24, 0x91, 0xaf, 0x50, 0xa1, 0xf4, 0x70, 0x39 , 0x99, 0x7c, 0x3a, 0x85, 0x23, 0xb8, 0xb4, 0x7a, 0xfc, 0x02, 0x36, 0x5b, 0x25, 0x55, 0x97, 0x31 , 0x2d, 0x5d, 0xfa, 0x98, 0xe3, 0x8a, 0x92, 0xae, 0x05, 0xdf, 0x29, 0x10, 0x67, 0x6c, 0xba, 0xc9 , 0xd3, 0x00, 0xe6, 0xcf, 0xe1, 0x9e, 0xa8, 0x2c, 0x63, 0x16, 0x01, 0x3f, 0x58, 0xe2, 0x89, 0xa9 , 0x0d, 0x38, 0x34, 0x1b, 0xab, 0x33, 0xff, 0xb0, 0xbb, 0x48, 0x0c, 0x5f, 0xb9, 0xb1, 0xcd, 0x2e , 0xc5, 0xf3, 0xdb, 0x47, 0xe5, 0xa5, 0x9c, 0x77, 0x0a, 0xa6, 0x20, 0x68, 0xfe, 0x7f, 0xc1, 0xad ]