Add Curve_Ed25519

Crypto/ECC.hs

@@ -17,6 +17,7 @@ module Crypto.ECC
     , Curve_P521R1(..)
     , Curve_X25519(..)
     , Curve_X448(..)
+    , Curve_Ed25519(..)
     , EllipticCurve(..)
     , EllipticCurveDH(..)
     , EllipticCurveArith(..)
@@ -25,6 +26,7 @@ module Crypto.ECC
     ) where
 
 import qualified Crypto.PubKey.ECC.P256 as P256
+import qualified Crypto.ECC.Ed25519 as Ed25519
 import qualified Crypto.ECC.Simple.Types as Simple
 import qualified Crypto.ECC.Simple.Prim as Simple
 import           Crypto.Random
@@ -225,6 +227,23 @@ instance EllipticCurveDH Curve_X448 where
       where secret = X448.dh p s
     ecdh prx s p = checkNonZeroDH (ecdhRaw prx s p)
 
+data Curve_Ed25519 = Curve_Ed25519
+    deriving (Show,Data,Typeable)
+
+instance EllipticCurve Curve_Ed25519 where
+    type Point Curve_Ed25519 = Ed25519.Point
+    type Scalar Curve_Ed25519 = Ed25519.Scalar
+    curveSizeBits _ = 255
+    curveGenerateScalar _ = Ed25519.scalarGenerate
+    curveGenerateKeyPair _ = toKeyPair <$> Ed25519.scalarGenerate
+      where toKeyPair scalar = KeyPair (Ed25519.toPoint scalar) scalar
+    encodePoint _ point = Ed25519.pointEncode point
+    decodePoint _ bs = Ed25519.pointDecode bs
+
+instance EllipticCurveArith Curve_Ed25519 where
+    pointAdd _ a b = Ed25519.pointAdd a b
+    pointSmul _ s p = Ed25519.pointMul s p
+
 checkNonZeroDH :: SharedSecret -> CryptoFailable SharedSecret
 checkNonZeroDH s@(SharedSecret b)
     | B.constAllZero b = CryptoFailed CryptoError_ScalarMultiplicationInvalid