{-# LANGUAGE DeriveDataTypeable #-} -- | -- Module : Crypto.Types.PubKey.DSA -- License : BSD-style -- Maintainer : Vincent Hanquez <vincent@snarc.org> -- Stability : Stable -- Portability : Excellent -- -- references: -- <https://tools.ietf.org/html/rfc6979> -- module Crypto.Types.PubKey.DSA ( Params(..) , Signature(..) , PublicNumber , PublicKey(..) , PrivateNumber , PrivateKey(..) , KeyPair(..) , toPublicKey , toPrivateKey ) where import Data.Data import Data.ASN1.Types -- | DSA Public Number, usually embedded in DSA Public Key type PublicNumber = Integer -- | DSA Private Number, usually embedded in DSA Private Key type PrivateNumber = Integer -- | Represent DSA parameters namely P, G, and Q. data Params = Params { params_p :: Integer -- ^ DSA p , params_g :: Integer -- ^ DSA g , params_q :: Integer -- ^ DSA q } deriving (Show,Read,Eq,Data,Typeable) instance ASN1Object Params where toASN1 params = \xs -> Start Sequence : IntVal (params_p params) : IntVal (params_q params) : IntVal (params_g params) : End Sequence : xs fromASN1 (Start Sequence:IntVal p:IntVal q:IntVal g:End Sequence:xs) = Right (Params { params_p = p, params_g = g, params_q = q }, xs) fromASN1 _ = Left "fromASN1: DSA.Params: unexpected format" -- | Represent a DSA signature namely R and S. data Signature = Signature { sign_r :: Integer -- ^ DSA r , sign_s :: Integer -- ^ DSA s } deriving (Show,Read,Eq,Data,Typeable) instance ASN1Object Signature where toASN1 sign = \xs -> Start Sequence : IntVal (sign_r sign) : IntVal (sign_s sign) : End Sequence : xs fromASN1 (Start Sequence:IntVal r:IntVal s:End Sequence:xs) = Right (Signature { sign_r = r, sign_s = s }, xs) fromASN1 _ = Left "fromASN1: DSA.Signature: unexpected format" -- | Represent a DSA public key. data PublicKey = PublicKey { public_params :: Params -- ^ DSA parameters , public_y :: PublicNumber -- ^ DSA public Y } deriving (Show,Read,Eq,Data,Typeable) -- DSA public key serialization doesn't typically look like this. -- However to provide an instance we serialize params and the public -- number together. instance ASN1Object PublicKey where toASN1 pubKey = \xs -> Start Sequence : IntVal (params_p params) : IntVal (params_q params) : IntVal (params_g params) : End Sequence : IntVal (public_y pubKey) : xs where params = public_params pubKey fromASN1 l = case fromASN1 l of Left err -> Left err Right (dsaParams, ls) -> case ls of IntVal dsaPub : ls2 -> Right (PublicKey dsaParams dsaPub, ls2) _ -> Left "fromASN1: DSA.PublicKey: unexpected format" -- | Represent a DSA private key. -- -- Only x need to be secret. -- the DSA parameters are publicly shared with the other side. data PrivateKey = PrivateKey { private_params :: Params -- ^ DSA parameters , private_x :: PrivateNumber -- ^ DSA private X } deriving (Show,Read,Eq,Data,Typeable) -- | Represent a DSA key pair data KeyPair = KeyPair Params PublicNumber PrivateNumber deriving (Show,Read,Eq,Data,Typeable) instance ASN1Object KeyPair where toASN1 (KeyPair params pub priv) = \xs -> Start Sequence : IntVal 0 : IntVal (params_p params) : IntVal (params_q params) : IntVal (params_g params) : IntVal pub : IntVal priv : End Sequence : xs fromASN1 (Start Sequence : IntVal n : xs) | n == 0 = case xs of IntVal p : IntVal q : IntVal g : IntVal pub : IntVal priv : End Sequence : xs2 -> let params = Params { params_p = p, params_g = g, params_q = q } in Right (KeyPair params pub priv, xs2) _ -> Left "fromASN1: DSA.KeyPair: invalid format (version=0)" | otherwise = Left "fromASN1: DSA.KeyPair: unknown format" fromASN1 _ = Left "fromASN1: DSA.KeyPair: unexpected format" -- | Public key of a DSA Key pair toPublicKey :: KeyPair -> PublicKey toPublicKey (KeyPair params pub _) = PublicKey params pub -- | Private key of a DSA Key pair toPrivateKey :: KeyPair -> PrivateKey toPrivateKey (KeyPair params _ priv) = PrivateKey params priv