{-# LANGUAGE GeneralizedNewtypeDeriving #-} -- | -- Module : Crypto.PubKey.DH -- License : BSD-style -- Maintainer : Vincent Hanquez <vincent@snarc.org> -- Stability : experimental -- Portability : Good -- module Crypto.PubKey.DH ( Params(..) , PublicNumber , PrivateNumber , SharedKey , generateParams , generatePrivate , calculatePublic , generatePublic , getShared ) where import Crypto.Number.ModArithmetic (expSafe) import Crypto.Number.Prime (generateSafePrime) import Crypto.Number.Generate (generateMax) import Crypto.Types.PubKey.DH import Crypto.Random import Control.Arrow (first) -- | generate params from a specific generator (2 or 5 are common values) -- we generate a safe prime (a prime number of the form 2p+1 where p is also prime) generateParams :: CPRG g => g -> Int -> Integer -> (Params, g) generateParams rng bits generator = first (\p -> Params p generator) $ generateSafePrime rng bits -- | generate a private number with no specific property -- this number is usually called X in DH text. generatePrivate :: CPRG g => g -> Params -> (PrivateNumber, g) generatePrivate rng (Params p _) = first PrivateNumber $ generateMax rng p -- | calculate the public number from the parameters and the private key -- this number is usually called Y in DH text. calculatePublic :: Params -> PrivateNumber -> PublicNumber calculatePublic (Params p g) (PrivateNumber x) = PublicNumber $ expSafe g x p -- | calculate the public number from the parameters and the private key -- this number is usually called Y in DH text. -- -- DEPRECATED use calculatePublic generatePublic :: Params -> PrivateNumber -> PublicNumber generatePublic = calculatePublic -- commented until 0.3 {-# DEPRECATED generatePublic "use calculatePublic" #-} -- | generate a shared key using our private number and the other party public number getShared :: Params -> PrivateNumber -> PublicNumber -> SharedKey getShared (Params p _) (PrivateNumber x) (PublicNumber y) = SharedKey $ expSafe y x p