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[Blowfish] use the key directly without stretching it all over the memory

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This commit is contained in:
Vincent Hanquez 2015-04-11 16:02:45 +01:00
parent 4247520e91
commit 26fdfcf563
1 changed files with 14 additions and 19 deletions
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33
Crypto/Cipher/Blowfish/Primitive.hs
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@ -18,10 +18,9 @@ module Crypto.Cipher.Blowfish.Primitive
, decrypt
) where
import Control.Monad (forM_)
import Control.Monad (forM_, when)
import Data.Bits
import Data.Word
import qualified Data.ByteString as B
import Crypto.Error
import Crypto.Internal.Compat
@ -53,23 +52,9 @@ cipher ctx b
initBlowfish :: ByteArray key => key -> CryptoFailable Context
initBlowfish key
| len > (448 `div` 8) = CryptoFailed $ CryptoError_KeySizeInvalid
| len == 0 = keyFromByteString (B.replicate (18*4) 0)
| otherwise = keyFromByteString . B.pack . take (18*4) . cycle . B.unpack . byteArrayToBS $ key
| otherwise = CryptoPassed $ makeKeySchedule key
where len = byteArrayLength key
keyFromByteString :: B.ByteString -> CryptoFailable Context
keyFromByteString k
| B.length k /= (18 * 4) = CryptoFailed CryptoError_KeySizeInvalid
| otherwise = CryptoPassed . makeKeySchedule . w8tow32 . B.unpack $ k
where
w8tow32 :: [Word8] -> [Word32]
w8tow32 [] = []
w8tow32 (a:b:c:d:xs) = ( (fromIntegral a `shiftL` 24) .|.
(fromIntegral b `shiftL` 16) .|.
(fromIntegral c `shiftL` 8) .|.
(fromIntegral d) ) : w8tow32 xs
w8tow32 _ = error $ "internal error: Crypto.Cipher.Blowfish:keyFromByteString"
coreCrypto :: Context -> Word64 -> Word64
coreCrypto (BF p s0 s1 s2 s3) input = doRound input 0
where
@ -91,11 +76,21 @@ coreCrypto (BF p s0 s1 s2 s3) input = doRound input 0
d = s3 (fromIntegral $ t .&. 0xff)
in fromIntegral (((a + b) `xor` c) + d) `shiftL` 32
makeKeySchedule :: [Word32] -> Context
makeKeySchedule :: ByteArray key => key -> Context
makeKeySchedule key =
let v = unsafeDoIO $ do
let len = byteArrayLength key
mv <- createKeySchedule
forM_ (zip key [0..17]) $ \(k, i) -> mutableArrayWriteXor32 mv i k
when (len > 0) $ forM_ [0..17] $ \i -> do
let a = byteArrayIndex key ((i * 4 + 0) `mod` len)
b = byteArrayIndex key ((i * 4 + 1) `mod` len)
c = byteArrayIndex key ((i * 4 + 2) `mod` len)
d = byteArrayIndex key ((i * 4 + 3) `mod` len)
k = (fromIntegral a `shiftL` 24) .|.
(fromIntegral b `shiftL` 16) .|.
(fromIntegral c `shiftL` 8) .|.
(fromIntegral d)
mutableArrayWriteXor32 mv i k
prepare mv
mutableArray32Freeze mv
in BF (\i -> arrayRead32 v i)