-- |
-- Module : Crypto.PubKey.Ed25519
-- License : BSD-style
-- Maintainer : Vincent Hanquez <vincent@snarc.org>
-- Stability : experimental
-- Portability : unknown
--
-- Ed25519 support
--
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
module Crypto.PubKey.Ed25519
( SecretKey
, PublicKey
, Signature
-- * Size constants
, publicKeySize
, secretKeySize
, signatureSize
-- * Smart constructors
, signature
, publicKey
, secretKey
-- * methods
, toPublic
, sign
, verify
, generateSecretKey
) where
import Data.Word
import Foreign.C.Types
import Foreign.Ptr
import Crypto.Error
import Crypto.Internal.ByteArray (ByteArrayAccess, Bytes,
ScrubbedBytes, withByteArray)
import qualified Crypto.Internal.ByteArray as B
import Crypto.Internal.Compat
import Crypto.Internal.Imports
import Crypto.Random
-- | An Ed25519 Secret key
newtype SecretKey = SecretKey ScrubbedBytes
deriving (Show,Eq,ByteArrayAccess,NFData)
-- | An Ed25519 public key
newtype PublicKey = PublicKey Bytes
deriving (Show,Eq,ByteArrayAccess,NFData)
-- | An Ed25519 signature
newtype Signature = Signature Bytes
deriving (Show,Eq,ByteArrayAccess,NFData)
-- | Try to build a public key from a bytearray
publicKey :: ByteArrayAccess ba => ba -> CryptoFailable PublicKey
publicKey bs
| B.length bs == publicKeySize =
CryptoPassed $ PublicKey $ B.copyAndFreeze bs (\_ -> return ())
| otherwise =
CryptoFailed $ CryptoError_PublicKeySizeInvalid
-- | Try to build a secret key from a bytearray
secretKey :: ByteArrayAccess ba => ba -> CryptoFailable SecretKey
secretKey bs
| B.length bs == secretKeySize = unsafeDoIO $ withByteArray bs initialize
| otherwise = CryptoFailed CryptoError_SecretKeyStructureInvalid
where
initialize inp = do
valid <- isValidPtr inp
if valid
then (CryptoPassed . SecretKey) <$> B.copy bs (\_ -> return ())
else return $ CryptoFailed CryptoError_SecretKeyStructureInvalid
isValidPtr _ =
return True
{-# NOINLINE secretKey #-}
-- | Try to build a signature from a bytearray
signature :: ByteArrayAccess ba => ba -> CryptoFailable Signature
signature bs
| B.length bs == signatureSize =
CryptoPassed $ Signature $ B.copyAndFreeze bs (\_ -> return ())
| otherwise =
CryptoFailed CryptoError_SecretKeyStructureInvalid
-- | Create a public key from a secret key
toPublic :: SecretKey -> PublicKey
toPublic (SecretKey sec) = PublicKey <$>
B.allocAndFreeze publicKeySize $ \result ->
withByteArray sec $ \psec ->
ccryptonite_ed25519_publickey psec result
{-# NOINLINE toPublic #-}
-- | Sign a message using the key pair
sign :: ByteArrayAccess ba => SecretKey -> PublicKey -> ba -> Signature
sign secret public message =
Signature $ B.allocAndFreeze signatureSize $ \sig ->
withByteArray secret $ \sec ->
withByteArray public $ \pub ->
withByteArray message $ \msg ->
ccryptonite_ed25519_sign msg (fromIntegral msgLen) sec pub sig
where
!msgLen = B.length message
-- | Verify a message
verify :: ByteArrayAccess ba => PublicKey -> ba -> Signature -> Bool
verify public message signatureVal = unsafeDoIO $
withByteArray signatureVal $ \sig ->
withByteArray public $ \pub ->
withByteArray message $ \msg -> do
r <- ccryptonite_ed25519_sign_open msg (fromIntegral msgLen) pub sig
return (r == 0)
where
!msgLen = B.length message
-- | Generate a secret key
generateSecretKey :: MonadRandom m => m SecretKey
generateSecretKey = SecretKey <$> getRandomBytes secretKeySize
-- | A public key is 32 bytes
publicKeySize :: Int
publicKeySize = 32
-- | A secret key is 32 bytes
secretKeySize :: Int
secretKeySize = 32
-- | A signature is 64 bytes
signatureSize :: Int
signatureSize = 64
foreign import ccall "cryptonite_ed25519_publickey"
ccryptonite_ed25519_publickey :: Ptr SecretKey -- secret key
-> Ptr PublicKey -- public key
-> IO ()
foreign import ccall "cryptonite_ed25519_sign_open"
ccryptonite_ed25519_sign_open :: Ptr Word8 -- message
-> CSize -- message len
-> Ptr PublicKey -- public
-> Ptr Signature -- signature
-> IO CInt
foreign import ccall "cryptonite_ed25519_sign"
ccryptonite_ed25519_sign :: Ptr Word8 -- message
-> CSize -- message len
-> Ptr SecretKey -- secret
-> Ptr PublicKey -- public
-> Ptr Signature -- signature
-> IO ()