License	BSD-style
Maintainer	Vincent Hanquez <vincent@snarc.org>
Stability	experimental
Portability	unknown
Safe Haskell	None
Language	Haskell2010

Crypto.PubKey.ECC.DH

Description

Elliptic curve Diffie Hellman

Synopsis

data Curve
type PublicPoint = Point
type PrivateNumber = Integer
newtype SharedKey = SharedKey ScrubbedBytes
generatePrivate :: MonadRandom m => Curve -> m PrivateNumber
calculatePublic :: Curve -> PrivateNumber -> PublicPoint
getShared :: Curve -> PrivateNumber -> PublicPoint -> SharedKey
tryGetShared :: Curve -> PrivateNumber -> PublicPoint -> CryptoFailable SharedKey

Documentation

data Curve Source #

Define either a binary curve or a prime curve.

Instances

Instances details

Data Curve Source #
Instance details Defined in Crypto.PubKey.ECC.Types Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Curve -> c Curve # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Curve # toConstr :: Curve -> Constr # dataTypeOf :: Curve -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Curve) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Curve) # gmapT :: (forall b. Data b => b -> b) -> Curve -> Curve # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Curve -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Curve -> r # gmapQ :: (forall d. Data d => d -> u) -> Curve -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Curve -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Curve -> m Curve # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Curve -> m Curve # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Curve -> m Curve #
Read Curve Source #
Instance details Defined in Crypto.PubKey.ECC.Types Methods readsPrec :: Int -> ReadS Curve # readList :: ReadS [Curve] # readPrec :: ReadPrec Curve # readListPrec :: ReadPrec [Curve] #
Show Curve Source #
Instance details Defined in Crypto.PubKey.ECC.Types Methods showsPrec :: Int -> Curve -> ShowS # show :: Curve -> String # showList :: [Curve] -> ShowS #
Eq Curve Source #
Instance details Defined in Crypto.PubKey.ECC.Types Methods (==) :: Curve -> Curve -> Bool # (/=) :: Curve -> Curve -> Bool #

type PublicPoint = Point Source #

ECC Public Point

type PrivateNumber = Integer Source #

ECC Private Number

newtype SharedKey Source #

Represent Diffie Hellman shared secret.

Constructors

SharedKey ScrubbedBytes

Instances

Instances details

Show SharedKey Source #
Instance details Defined in Crypto.PubKey.DH Methods showsPrec :: Int -> SharedKey -> ShowS # show :: SharedKey -> String # showList :: [SharedKey] -> ShowS #
NFData SharedKey Source #
Instance details Defined in Crypto.PubKey.DH Methods rnf :: SharedKey -> () #
Eq SharedKey Source #
Instance details Defined in Crypto.PubKey.DH Methods (==) :: SharedKey -> SharedKey -> Bool # (/=) :: SharedKey -> SharedKey -> Bool #
ByteArrayAccess SharedKey Source #
Instance details Defined in Crypto.PubKey.DH Methods length :: SharedKey -> Int # withByteArray :: SharedKey -> (Ptr p -> IO a) -> IO a # copyByteArrayToPtr :: SharedKey -> Ptr p -> IO () #

generatePrivate :: MonadRandom m => Curve -> m PrivateNumber Source #

Generating a private number d.

calculatePublic :: Curve -> PrivateNumber -> PublicPoint Source #

Generating a public point Q.

getShared :: Curve -> PrivateNumber -> PublicPoint -> SharedKey Source #

Generating a shared key using our private number and the other party public point.

This raises the CryptoError that tryGetShared reports. Use tryGetShared where the failure has to be handled.

tryGetShared :: Curve -> PrivateNumber -> PublicPoint -> CryptoFailable SharedKey Source #

Generating a shared key using our private number and the other party public point, reporting a rejected point instead of raising.

The public point comes from the other party, so it is checked before it is multiplied. A point that does not satisfy the curve equation is reported as CryptoError_PointCoordinatesInvalid.

Satisfying the equation is not by itself membership of the subgroup the base point generates; the two coincide only when the cofactor is 1. On a curve whose cofactor is above 1 the other party can offer a point of small order, and the value that comes back then depends on our private number only through its residue modulo that order, which hands them those bits. So the point is also required to be in the subgroup, by isPointInSubgroup, and is reported as CryptoError_PointSubgroupInvalid when it is not. That check costs one further scalar multiplication, and is skipped where the cofactor is 1 and it cannot fail.

An exchange that yields the point at infinity, and so has no x coordinate to derive the key from, is reported as CryptoError_ScalarMultiplicationInvalid.