module Crypto.Cipher.DH
( Params
, PublicNumber
, PrivateNumber
, SharedKey
, generateParams
, generatePrivate
, generatePublic
, getShared
) where
import Number.ModArithmetic (exponantiation_rtl_binary)
import Number.Prime (generateSafePrime)
import Number.Generate (generateOfSize)
import Crypto.Random
import Control.Arrow (first)
type Params = (Integer,Integer)
newtype PublicNumber = PublicNumber Integer
deriving (Show,Read,Eq,Enum,Real,Num,Ord)
newtype PrivateNumber = PrivateNumber Integer
deriving (Show,Read,Eq,Enum,Real,Num,Ord)
newtype SharedKey = SharedKey Integer
deriving (Show,Read,Eq,Enum,Real,Num,Ord)
generateParams :: CryptoRandomGen g => g -> Int -> Integer -> Either GenError (Params, g)
generateParams rng bits generator =
either Left (Right . first (\p -> (p, generator))) $ generateSafePrime rng bits
generatePrivate :: CryptoRandomGen g => g -> Int -> Either GenError (PrivateNumber, g)
generatePrivate rng bits = either Left (Right . first PrivateNumber) $ generateOfSize rng bits
generatePublic :: Params -> PrivateNumber -> PublicNumber
generatePublic (p,g) (PrivateNumber x) = PublicNumber $ exponantiation_rtl_binary g x p
getShared :: Params -> PrivateNumber -> PublicNumber -> SharedKey
getShared (p,_) (PrivateNumber x) (PublicNumber y) = SharedKey $ exponantiation_rtl_binary y x p