a879845434
This is actually a lie: the condition is tested in both curve implementations but not returned by the Haskell API. Will be a reminder to add this in the future. A function 'allocRetAndFreeze' could be useful.
119 lines
4.0 KiB
Haskell
119 lines
4.0 KiB
Haskell
-- |
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-- Module : Crypto.PubKey.Curve448
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-- License : BSD-style
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-- Maintainer : John Galt <jgalt@centromere.net>
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-- Stability : experimental
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-- Portability : unknown
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--
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-- Curve448 support
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--
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-- Internally uses Decaf point compression to omit the cofactor
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-- and implementation by Mike Hamburg. Externally API and
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-- data types are compatible with the encoding specified in RFC 7748.
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--
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{-# LANGUAGE GeneralizedNewtypeDeriving #-}
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{-# LANGUAGE MagicHash #-}
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module Crypto.PubKey.Curve448
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( SecretKey
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, PublicKey
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, DhSecret
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-- * Smart constructors
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, dhSecret
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, publicKey
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, secretKey
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-- * methods
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, dh
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, toPublic
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, generateSecretKey
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) where
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import Data.Word
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import Foreign.Ptr
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import GHC.Ptr
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import Crypto.Error
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import Crypto.Random
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import Crypto.Internal.Compat
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import Crypto.Internal.Imports
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import Crypto.Internal.ByteArray (ByteArrayAccess, ScrubbedBytes, Bytes, withByteArray)
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import qualified Crypto.Internal.ByteArray as B
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-- | A Curve448 Secret key
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newtype SecretKey = SecretKey ScrubbedBytes
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deriving (Show,Eq,ByteArrayAccess,NFData)
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-- | A Curve448 public key
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newtype PublicKey = PublicKey Bytes
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deriving (Show,Eq,ByteArrayAccess,NFData)
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-- | A Curve448 Diffie Hellman secret related to a
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-- public key and a secret key.
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newtype DhSecret = DhSecret ScrubbedBytes
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deriving (Show,Eq,ByteArrayAccess,NFData)
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-- | Try to build a public key from a bytearray
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publicKey :: ByteArrayAccess bs => bs -> CryptoFailable PublicKey
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publicKey bs
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| B.length bs == x448_bytes = CryptoPassed $ PublicKey $ B.copyAndFreeze bs (\_ -> return ())
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| otherwise = CryptoFailed CryptoError_PublicKeySizeInvalid
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-- | Try to build a secret key from a bytearray
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secretKey :: ByteArrayAccess bs => bs -> CryptoFailable SecretKey
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secretKey bs
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| B.length bs == x448_bytes = unsafeDoIO $
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withByteArray bs $ \inp -> do
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valid <- isValidPtr inp
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if valid
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then (CryptoPassed . SecretKey) <$> B.copy bs (\_ -> return ())
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else return $ CryptoFailed CryptoError_SecretKeyStructureInvalid
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| otherwise = CryptoFailed CryptoError_SecretKeySizeInvalid
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where
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isValidPtr :: Ptr Word8 -> IO Bool
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isValidPtr _ =
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return True
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{-# NOINLINE secretKey #-}
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-- | Create a DhSecret from a bytearray object
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dhSecret :: ByteArrayAccess b => b -> CryptoFailable DhSecret
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dhSecret bs
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| B.length bs == x448_bytes = CryptoPassed $ DhSecret $ B.copyAndFreeze bs (\_ -> return ())
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| otherwise = CryptoFailed CryptoError_SharedSecretSizeInvalid
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-- | Compute the Diffie Hellman secret from a public key and a secret key.
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--
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-- This implementation may return an all-zero value as it does not check for
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-- the condition.
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dh :: PublicKey -> SecretKey -> DhSecret
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dh (PublicKey pub) (SecretKey sec) = DhSecret <$>
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B.allocAndFreeze x448_bytes $ \result ->
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withByteArray sec $ \psec ->
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withByteArray pub $ \ppub ->
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decaf_x448 result ppub psec
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{-# NOINLINE dh #-}
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-- | Create a public key from a secret key
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toPublic :: SecretKey -> PublicKey
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toPublic (SecretKey sec) = PublicKey <$>
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B.allocAndFreeze x448_bytes $ \result ->
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withByteArray sec $ \psec ->
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decaf_x448_derive_public_key result psec
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{-# NOINLINE toPublic #-}
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-- | Generate a secret key.
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generateSecretKey :: MonadRandom m => m SecretKey
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generateSecretKey = SecretKey <$> getRandomBytes x448_bytes
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x448_bytes :: Int
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x448_bytes = 448 `quot` 8
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foreign import ccall "cryptonite_decaf_x448"
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decaf_x448 :: Ptr Word8 -- ^ public
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-> Ptr Word8 -- ^ basepoint
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-> Ptr Word8 -- ^ secret
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-> IO ()
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foreign import ccall "cryptonite_decaf_x448_derive_public_key"
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decaf_x448_derive_public_key :: Ptr Word8 -- ^ public
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-> Ptr Word8 -- ^ secret
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-> IO ()
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