1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
|
-- |
-- Module : Crypto.PubKey.ECC.DH
-- License : BSD-style
-- Maintainer : Vincent Hanquez <vincent@snarc.org>
-- Stability : experimental
-- Portability : unknown
--
-- Elliptic curve Diffie Hellman
module Crypto.PubKey.ECC.DH (
Curve,
PublicPoint,
PrivateNumber,
SharedKey (..),
generatePrivate,
calculatePublic,
getShared,
) where
import Crypto.Number.Generate (generateMax)
import Crypto.Number.Serialize (i2ospOf_)
import Crypto.PubKey.DH (SharedKey (..))
import Crypto.PubKey.ECC.Prim (pointMul)
import Crypto.PubKey.ECC.Types (
Curve,
Point (..),
PrivateNumber,
PublicPoint,
common_curve,
curveSizeBits,
ecc_g,
ecc_n,
)
import Crypto.Random.Types
-- | Generating a private number d.
generatePrivate :: MonadRandom m => Curve -> m PrivateNumber
generatePrivate curve = generateMax n
where
n = ecc_n $ common_curve curve
-- | Generating a public point Q.
calculatePublic :: Curve -> PrivateNumber -> PublicPoint
calculatePublic curve d = q
where
g = ecc_g $ common_curve curve
q = pointMul curve d g
-- | Generating a shared key using our private number and
-- the other party public point.
getShared :: Curve -> PrivateNumber -> PublicPoint -> SharedKey
getShared curve db qa = SharedKey $ i2ospOf_ ((nbBits + 7) `div` 8) x
where
x = case pointMul curve db qa of
Point x' _ -> x'
_ -> error "getShared"
nbBits = curveSizeBits curve
|
