add Poly1305 module (non-exposed)

Crypto/MAC/Poly1305.hs

@@ -0,0 +1,97 @@
+{-# LANGUAGE ForeignFunctionInterface #-}
+
+-- |
+-- Module      : Crypto.MAC.Poly1305
+-- License     : BSD-style
+-- Maintainer  : Vincent Hanquez <vincent@snarc.org>
+-- Stability   : experimental
+-- Portability : unknown
+--
+-- Poly1305 implementation
+--
+module Crypto.MAC.Poly1305
+    ( Ctx
+    , Auth
+
+    -- * Incremental MAC Functions
+    , initialize -- :: Ctx
+    , update     -- :: Ctx -> ByteString -> Ctx
+    , updates    -- :: Ctx -> [ByteString] -> Ctx
+    , finalize   -- :: Ctx -> Auth
+    -- * One-pass MAC function
+    , auth
+    ) where
+
+import Prelude hiding (init)
+import Foreign.Ptr
+import Foreign.C.Types
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Internal as B
+import Data.ByteString (ByteString)
+import Data.Word
+import Data.Byteable
+import System.IO.Unsafe
+import Data.SecureMem
+
+-- | Poly1305 Context
+newtype Ctx = Ctx SecureMem
+
+-- | Poly1305 Auth
+newtype Auth = Auth ByteString
+
+instance Byteable Auth where
+    toBytes (Auth b) = b
+
+foreign import ccall unsafe "cryptonite_poly1305.h cryptonite_poly1305_init"
+    c_poly1305_init :: Ptr Ctx -> Ptr Word8 -> IO ()
+
+foreign import ccall "cryptonite_poly1305.h cryptonite_poly1305_update"
+    c_poly1305_update :: Ptr Ctx -> Ptr Word8 -> CUInt -> IO ()
+
+foreign import ccall unsafe "cryptonite_poly1305.h cryptonite_poly1305_finalize"
+    c_poly1305_finalize :: Ptr Word8 -> Ptr Ctx -> IO ()
+
+-- | initialize a Poly1305 context
+initialize :: Byteable key
+     => key
+     -> Ctx
+initialize key
+    | byteableLength key /= 32 = error "Poly1305: key length expected 32 bytes"
+    | otherwise          = Ctx $ unsafePerformIO $ do
+        withBytePtr key $ \keyPtr ->
+            createSecureMem 64 {- FIXME -} $ \ctxPtr ->
+                c_poly1305_init (castPtr ctxPtr) keyPtr
+{-# NOINLINE initialize #-}
+
+-- | update a context with a bytestring
+update :: Ctx -> ByteString -> Ctx
+update (Ctx prevCtx) d = unsafePerformIO $ do
+    ctx <- secureMemCopy prevCtx
+    withSecureMemPtr ctx $ \ctxPtr ->
+        withBytePtr d $ \dataPtr ->
+            c_poly1305_update (castPtr ctxPtr) dataPtr (fromIntegral $ B.length d)
+    return $ Ctx ctx
+{-# NOINLINE update #-}
+
+-- | updates a context with multiples bytestring
+updates :: Ctx -> [ByteString] -> Ctx
+updates (Ctx prevCtx) d = unsafePerformIO $ do
+    ctx <- secureMemCopy prevCtx
+    withSecureMemPtr ctx (loop d . castPtr)
+    return $ Ctx ctx
+  where loop []     _      = return ()
+        loop (x:xs) ctxPtr = do
+            withBytePtr x $ \dataPtr -> c_poly1305_update ctxPtr dataPtr (fromIntegral $ B.length x)
+            loop xs ctxPtr
+{-# NOINLINE updates #-}
+
+-- | finalize the context into a digest bytestring
+finalize :: Ctx -> Auth
+finalize (Ctx prevCtx) = Auth $ B.unsafeCreate 16 $ \dst -> do
+    ctx <- secureMemCopy prevCtx
+    withSecureMemPtr ctx $ \ctxPtr -> c_poly1305_finalize dst (castPtr ctxPtr)
+{-# NOINLINE finalize #-}
+
+-- | Auth
+auth :: Byteable key => key -> ByteString -> Auth
+auth key = finalize . update (initialize key)

cryptonite.cabal

@@ -21,6 +21,7 @@ source-repository head
 
 Library
   Exposed-modules:   Crypto.Cipher.ChaCha
+  Other-modules:     Crypto.MAC.Poly1305
   Build-depends:     base >= 4 && < 5
                    , bytestring
                    , securemem
@@ -28,6 +29,7 @@ Library
   ghc-options:       -Wall -fwarn-tabs -optc-O3
   default-language:  Haskell2010
   C-sources:         cbits/cryptonite_chacha.c
+                   , cbits/cryptonite_poly1305.c
   if (arch(i386) || arch(x86_64))
     CPP-options: -DARCH_IS_LITTLE_ENDIAN