-- SPDX-FileCopyrightText: 2020 Tocqueville Group
--
-- SPDX-License-Identifier: LicenseRef-MIT-TQ

-- | Secp256k1 cryptographic primitives.

module Tezos.Crypto.Secp256k1
  ( -- * Cryptographic primitive types
    PublicKey (..)
  , SecretKey
  , Signature (..)
  , detSecretKey
  , detSecretKeyDo
  , toPublic

  -- * Raw bytes (no checksums, tags or anything)
  , publicKeyToBytes
  , mkPublicKey
  , publicKeyLengthBytes
  , signatureToBytes
  , mkSignature
  , signatureLengthBytes

  -- * Formatting and parsing
  , formatPublicKey
  , mformatPublicKey
  , parsePublicKey
  , formatSignature
  , mformatSignature
  , parseSignature
  , formatSecretKey
  , parseSecretKey

  -- * Signing
  , sign
  , checkSignature
  ) where

import Crypto.Hash (Blake2b_256(..))
import qualified Crypto.PubKey.ECC.ECDSA as ECDSA
import qualified Crypto.PubKey.ECC.Generate as ECC.Generate
import Crypto.PubKey.ECC.Types (Curve(..), CurveName(..), getCurveByName)
import Crypto.Random (MonadRandom)
import Data.ByteArray (ByteArray, ByteArrayAccess)
import Fmt (Buildable, build)

import Michelson.Text
import Tezos.Crypto.Util

curve :: Curve
curve :: Curve
curve = CurveName -> Curve
getCurveByName CurveName
SEC_p256k1

----------------------------------------------------------------------------
-- Types, instances, conversions
----------------------------------------------------------------------------

-- | Secp256k1 public cryptographic key.
newtype PublicKey = PublicKey
  { PublicKey -> PublicKey
unPublicKey :: ECDSA.PublicKey
  } deriving stock (PublicKey -> PublicKey -> Bool
(PublicKey -> PublicKey -> Bool)
-> (PublicKey -> PublicKey -> Bool) -> Eq PublicKey
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: PublicKey -> PublicKey -> Bool
$c/= :: PublicKey -> PublicKey -> Bool
== :: PublicKey -> PublicKey -> Bool
$c== :: PublicKey -> PublicKey -> Bool
Eq, Int -> PublicKey -> ShowS
[PublicKey] -> ShowS
PublicKey -> String
(Int -> PublicKey -> ShowS)
-> (PublicKey -> String)
-> ([PublicKey] -> ShowS)
-> Show PublicKey
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [PublicKey] -> ShowS
$cshowList :: [PublicKey] -> ShowS
show :: PublicKey -> String
$cshow :: PublicKey -> String
showsPrec :: Int -> PublicKey -> ShowS
$cshowsPrec :: Int -> PublicKey -> ShowS
Show, (forall x. PublicKey -> Rep PublicKey x)
-> (forall x. Rep PublicKey x -> PublicKey) -> Generic PublicKey
forall x. Rep PublicKey x -> PublicKey
forall x. PublicKey -> Rep PublicKey x
forall a.
(forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
$cto :: forall x. Rep PublicKey x -> PublicKey
$cfrom :: forall x. PublicKey -> Rep PublicKey x
Generic)

instance NFData PublicKey where
  rnf :: PublicKey -> ()
rnf (PublicKey (ECDSA.PublicKey cu :: Curve
cu q :: PublicPoint
q))
    = Curve -> ()
rnfCurve Curve
cu () -> () -> ()
forall a b. a -> b -> b
`seq` PublicPoint -> ()
forall a. NFData a => a -> ()
rnf PublicPoint
q

-- | Secp256k1 secret cryptographic key.
newtype SecretKey = SecretKey
  { SecretKey -> KeyPair
unSecretKey :: ECDSA.KeyPair
  } deriving stock (Int -> SecretKey -> ShowS
[SecretKey] -> ShowS
SecretKey -> String
(Int -> SecretKey -> ShowS)
-> (SecretKey -> String)
-> ([SecretKey] -> ShowS)
-> Show SecretKey
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [SecretKey] -> ShowS
$cshowList :: [SecretKey] -> ShowS
show :: SecretKey -> String
$cshow :: SecretKey -> String
showsPrec :: Int -> SecretKey -> ShowS
$cshowsPrec :: Int -> SecretKey -> ShowS
Show, SecretKey -> SecretKey -> Bool
(SecretKey -> SecretKey -> Bool)
-> (SecretKey -> SecretKey -> Bool) -> Eq SecretKey
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: SecretKey -> SecretKey -> Bool
$c/= :: SecretKey -> SecretKey -> Bool
== :: SecretKey -> SecretKey -> Bool
$c== :: SecretKey -> SecretKey -> Bool
Eq, (forall x. SecretKey -> Rep SecretKey x)
-> (forall x. Rep SecretKey x -> SecretKey) -> Generic SecretKey
forall x. Rep SecretKey x -> SecretKey
forall x. SecretKey -> Rep SecretKey x
forall a.
(forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
$cto :: forall x. Rep SecretKey x -> SecretKey
$cfrom :: forall x. SecretKey -> Rep SecretKey x
Generic)

instance NFData SecretKey where
  rnf :: SecretKey -> ()
rnf (SecretKey (ECDSA.KeyPair cu :: Curve
cu pp :: PublicPoint
pp pn :: PrivateNumber
pn)) =
    Curve -> ()
rnfCurve Curve
cu () -> () -> ()
forall a b. a -> b -> b
`seq` (PublicPoint, PrivateNumber) -> ()
forall a. NFData a => a -> ()
rnf (PublicPoint
pp, PrivateNumber
pn)

-- | Deterministicaly generate a secret key from seed.
detSecretKey :: ByteString -> SecretKey
detSecretKey :: ByteString -> SecretKey
detSecretKey seed :: ByteString
seed = ByteString -> MonadPseudoRandom ChaChaDRG SecretKey -> SecretKey
forall a. ByteString -> MonadPseudoRandom ChaChaDRG a -> a
deterministic ByteString
seed (MonadPseudoRandom ChaChaDRG SecretKey -> SecretKey)
-> MonadPseudoRandom ChaChaDRG SecretKey -> SecretKey
forall a b. (a -> b) -> a -> b
$ MonadPseudoRandom ChaChaDRG SecretKey
forall (m :: * -> *). MonadRandom m => m SecretKey
detSecretKeyDo

detSecretKeyDo :: MonadRandom m => m SecretKey
detSecretKeyDo :: m SecretKey
detSecretKeyDo = KeyPair -> SecretKey
SecretKey (KeyPair -> SecretKey) -> m KeyPair -> m SecretKey
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> do
  (publicKey :: PublicKey
publicKey, privateKey :: PrivateKey
privateKey) <- Curve -> m (PublicKey, PrivateKey)
forall (m :: * -> *).
MonadRandom m =>
Curve -> m (PublicKey, PrivateKey)
ECC.Generate.generate Curve
curve
  KeyPair -> m KeyPair
forall (m :: * -> *) a. Monad m => a -> m a
return (KeyPair -> m KeyPair) -> KeyPair -> m KeyPair
forall a b. (a -> b) -> a -> b
$
    Curve -> PublicPoint -> PrivateNumber -> KeyPair
ECDSA.KeyPair Curve
curve (PublicKey -> PublicPoint
ECDSA.public_q PublicKey
publicKey) (PrivateKey -> PrivateNumber
ECDSA.private_d PrivateKey
privateKey)

-- | Create a public key from a secret key.
toPublic :: SecretKey -> PublicKey
toPublic :: SecretKey -> PublicKey
toPublic =
  PublicKey -> PublicKey
PublicKey (PublicKey -> PublicKey)
-> (SecretKey -> PublicKey) -> SecretKey -> PublicKey
forall b c a. (b -> c) -> (a -> b) -> a -> c
.
  Curve -> PublicPoint -> PublicKey
ECDSA.PublicKey Curve
curve (PublicPoint -> PublicKey)
-> (SecretKey -> PublicPoint) -> SecretKey -> PublicKey
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (\(ECDSA.KeyPair _ pp :: PublicPoint
pp _) -> PublicPoint
pp) (KeyPair -> PublicPoint)
-> (SecretKey -> KeyPair) -> SecretKey -> PublicPoint
forall b c a. (b -> c) -> (a -> b) -> a -> c
. SecretKey -> KeyPair
unSecretKey

-- | Secp256k1 cryptographic signature.
newtype Signature = Signature
  { Signature -> Signature
unSignature :: ECDSA.Signature
  } deriving stock (Int -> Signature -> ShowS
[Signature] -> ShowS
Signature -> String
(Int -> Signature -> ShowS)
-> (Signature -> String)
-> ([Signature] -> ShowS)
-> Show Signature
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [Signature] -> ShowS
$cshowList :: [Signature] -> ShowS
show :: Signature -> String
$cshow :: Signature -> String
showsPrec :: Int -> Signature -> ShowS
$cshowsPrec :: Int -> Signature -> ShowS
Show, Signature -> Signature -> Bool
(Signature -> Signature -> Bool)
-> (Signature -> Signature -> Bool) -> Eq Signature
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: Signature -> Signature -> Bool
$c/= :: Signature -> Signature -> Bool
== :: Signature -> Signature -> Bool
$c== :: Signature -> Signature -> Bool
Eq, (forall x. Signature -> Rep Signature x)
-> (forall x. Rep Signature x -> Signature) -> Generic Signature
forall x. Rep Signature x -> Signature
forall x. Signature -> Rep Signature x
forall a.
(forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
$cto :: forall x. Rep Signature x -> Signature
$cfrom :: forall x. Signature -> Rep Signature x
Generic)

instance NFData Signature where
  rnf :: Signature -> ()
rnf (Signature (ECDSA.Signature a :: PrivateNumber
a b :: PrivateNumber
b)) = PrivateNumber -> ()
forall a. NFData a => a -> ()
rnf PrivateNumber
a () -> () -> ()
forall a b. a -> b -> b
`seq` PrivateNumber -> ()
forall a. NFData a => a -> ()
rnf PrivateNumber
b

----------------------------------------------------------------------------
-- Conversion to/from raw bytes (no checksums, tags or anything)
----------------------------------------------------------------------------

-- | Convert a 'PublicKey' to raw bytes.
publicKeyToBytes :: forall ba. ByteArray ba => PublicKey -> ba
publicKeyToBytes :: PublicKey -> ba
publicKeyToBytes (PublicKey p :: PublicKey
p) =
  Curve -> PublicKey -> ba
forall ba. (ByteArray ba, HasCallStack) => Curve -> PublicKey -> ba
publicKeyToBytes_ Curve
curve PublicKey
p

-- | Make a 'PublicKey' from raw bytes.
mkPublicKey :: ByteArrayAccess ba => ba -> Either CryptoParseError PublicKey
mkPublicKey :: ba -> Either CryptoParseError PublicKey
mkPublicKey ba :: ba
ba = PublicKey -> PublicKey
PublicKey (PublicKey -> PublicKey)
-> Either CryptoParseError PublicKey
-> Either CryptoParseError PublicKey
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Curve -> ba -> Either CryptoParseError PublicKey
forall ba.
ByteArrayAccess ba =>
Curve -> ba -> Either CryptoParseError PublicKey
mkPublicKey_ Curve
curve ba
ba

publicKeyLengthBytes :: Integral n => n
publicKeyLengthBytes :: n
publicKeyLengthBytes = Curve -> n
forall n. Integral n => Curve -> n
publicKeyLengthBytes_ Curve
curve

-- | Convert a 'PublicKey' to raw bytes.
signatureToBytes :: ByteArray ba => Signature -> ba
signatureToBytes :: Signature -> ba
signatureToBytes (Signature sig :: Signature
sig) =
  Curve -> Signature -> ba
forall ba. ByteArray ba => Curve -> Signature -> ba
signatureToBytes_ Curve
curve Signature
sig

-- | Make a 'Signature' from raw bytes.
mkSignature :: ByteArray ba => ba -> Either CryptoParseError Signature
mkSignature :: ba -> Either CryptoParseError Signature
mkSignature ba :: ba
ba = Signature -> Signature
Signature (Signature -> Signature)
-> Either CryptoParseError Signature
-> Either CryptoParseError Signature
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Curve -> ba -> Either CryptoParseError Signature
forall ba.
ByteArray ba =>
Curve -> ba -> Either CryptoParseError Signature
mkSignature_ Curve
curve ba
ba

signatureLengthBytes :: Integral n => n
signatureLengthBytes :: n
signatureLengthBytes = Curve -> n
forall n. Integral n => Curve -> n
signatureLengthBytes_ Curve
curve

mkSecretKey :: ByteArray ba => ba -> Either CryptoParseError SecretKey
mkSecretKey :: ba -> Either CryptoParseError SecretKey
mkSecretKey = SecretKey -> Either CryptoParseError SecretKey
forall a b. b -> Either a b
Right (SecretKey -> Either CryptoParseError SecretKey)
-> (ba -> SecretKey) -> ba -> Either CryptoParseError SecretKey
forall b c a. (b -> c) -> (a -> b) -> a -> c
. KeyPair -> SecretKey
SecretKey (KeyPair -> SecretKey) -> (ba -> KeyPair) -> ba -> SecretKey
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Curve -> ba -> KeyPair
forall ba. ByteArray ba => Curve -> ba -> KeyPair
mkSecretKey_ Curve
curve

-- | Convert a 'PublicKey' to raw bytes.
secretKeyToBytes :: ByteArray ba => SecretKey -> ba
secretKeyToBytes :: SecretKey -> ba
secretKeyToBytes (SecretKey kp :: KeyPair
kp) =
  KeyPair -> ba
forall ba. ByteArray ba => KeyPair -> ba
secretKeyToBytes_ KeyPair
kp

----------------------------------------------------------------------------
-- Magic bytes
----------------------------------------------------------------------------

publicKeyTag :: ByteString
publicKeyTag :: ByteString
publicKeyTag = "\003\254\226\086"

-- | Base16 format is @11a2e0c9@
secretKeyTag :: ByteString
secretKeyTag :: ByteString
secretKeyTag = "\017\162\224\201"

signatureTag :: ByteString
signatureTag :: ByteString
signatureTag = "\013\115\101\019\063"

----------------------------------------------------------------------------
-- Formatting
----------------------------------------------------------------------------

formatPublicKey :: PublicKey -> Text
formatPublicKey :: PublicKey -> Text
formatPublicKey = ByteString -> ByteString -> Text
forall x. ByteArrayAccess x => ByteString -> x -> Text
formatImpl @ByteString ByteString
publicKeyTag (ByteString -> Text)
-> (PublicKey -> ByteString) -> PublicKey -> Text
forall b c a. (b -> c) -> (a -> b) -> a -> c
. PublicKey -> ByteString
forall ba. ByteArray ba => PublicKey -> ba
publicKeyToBytes

mformatPublicKey :: PublicKey -> MText
mformatPublicKey :: PublicKey -> MText
mformatPublicKey = HasCallStack => Text -> MText
Text -> MText
mkMTextUnsafe (Text -> MText) -> (PublicKey -> Text) -> PublicKey -> MText
forall b c a. (b -> c) -> (a -> b) -> a -> c
. PublicKey -> Text
formatPublicKey

instance Buildable PublicKey where
  build :: PublicKey -> Builder
build = Text -> Builder
forall p. Buildable p => p -> Builder
build (Text -> Builder) -> (PublicKey -> Text) -> PublicKey -> Builder
forall b c a. (b -> c) -> (a -> b) -> a -> c
. PublicKey -> Text
formatPublicKey

parsePublicKey :: Text -> Either CryptoParseError PublicKey
parsePublicKey :: Text -> Either CryptoParseError PublicKey
parsePublicKey = ByteString
-> (ByteString -> Either CryptoParseError PublicKey)
-> Text
-> Either CryptoParseError PublicKey
forall res.
ByteString
-> (ByteString -> Either CryptoParseError res)
-> Text
-> Either CryptoParseError res
parseImpl ByteString
publicKeyTag ByteString -> Either CryptoParseError PublicKey
forall ba.
ByteArrayAccess ba =>
ba -> Either CryptoParseError PublicKey
mkPublicKey

formatSignature :: Signature -> Text
formatSignature :: Signature -> Text
formatSignature = ByteString -> ByteString -> Text
forall x. ByteArrayAccess x => ByteString -> x -> Text
formatImpl @ByteString ByteString
signatureTag (ByteString -> Text)
-> (Signature -> ByteString) -> Signature -> Text
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Signature -> ByteString
forall ba. ByteArray ba => Signature -> ba
signatureToBytes

mformatSignature :: Signature -> MText
mformatSignature :: Signature -> MText
mformatSignature = HasCallStack => Text -> MText
Text -> MText
mkMTextUnsafe (Text -> MText) -> (Signature -> Text) -> Signature -> MText
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Signature -> Text
formatSignature

instance Buildable Signature where
  build :: Signature -> Builder
build = Text -> Builder
forall p. Buildable p => p -> Builder
build (Text -> Builder) -> (Signature -> Text) -> Signature -> Builder
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Signature -> Text
formatSignature

parseSignature :: Text -> Either CryptoParseError Signature
parseSignature :: Text -> Either CryptoParseError Signature
parseSignature = ByteString
-> (ByteString -> Either CryptoParseError Signature)
-> Text
-> Either CryptoParseError Signature
forall res.
ByteString
-> (ByteString -> Either CryptoParseError res)
-> Text
-> Either CryptoParseError res
parseImpl ByteString
signatureTag ByteString -> Either CryptoParseError Signature
forall ba. ByteArray ba => ba -> Either CryptoParseError Signature
mkSignature

formatSecretKey :: SecretKey -> Text
formatSecretKey :: SecretKey -> Text
formatSecretKey = ByteString -> ByteString -> Text
forall x. ByteArrayAccess x => ByteString -> x -> Text
formatImpl @ByteString ByteString
secretKeyTag (ByteString -> Text)
-> (SecretKey -> ByteString) -> SecretKey -> Text
forall b c a. (b -> c) -> (a -> b) -> a -> c
. SecretKey -> ByteString
forall ba. ByteArray ba => SecretKey -> ba
secretKeyToBytes

instance Buildable SecretKey where
  build :: SecretKey -> Builder
build = Text -> Builder
forall p. Buildable p => p -> Builder
build (Text -> Builder) -> (SecretKey -> Text) -> SecretKey -> Builder
forall b c a. (b -> c) -> (a -> b) -> a -> c
. SecretKey -> Text
formatSecretKey

parseSecretKey :: Text -> Either CryptoParseError SecretKey
parseSecretKey :: Text -> Either CryptoParseError SecretKey
parseSecretKey = ByteString
-> (ByteString -> Either CryptoParseError SecretKey)
-> Text
-> Either CryptoParseError SecretKey
forall res.
ByteString
-> (ByteString -> Either CryptoParseError res)
-> Text
-> Either CryptoParseError res
parseImpl ByteString
secretKeyTag ByteString -> Either CryptoParseError SecretKey
forall ba. ByteArray ba => ba -> Either CryptoParseError SecretKey
mkSecretKey

----------------------------------------------------------------------------
-- Signing
----------------------------------------------------------------------------

-- | Sign a message using the secret key.
sign :: MonadRandom m => SecretKey -> ByteString -> m Signature
sign :: SecretKey -> ByteString -> m Signature
sign (SecretKey keyPair :: KeyPair
keyPair) =
  (Signature -> Signature) -> m Signature -> m Signature
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap Signature -> Signature
Signature (m Signature -> m Signature)
-> (ByteString -> m Signature) -> ByteString -> m Signature
forall b c a. (b -> c) -> (a -> b) -> a -> c
. PrivateKey -> Blake2b_256 -> ByteString -> m Signature
forall msg hash (m :: * -> *).
(ByteArrayAccess msg, HashAlgorithm hash, MonadRandom m) =>
PrivateKey -> hash -> msg -> m Signature
ECDSA.sign (KeyPair -> PrivateKey
ECDSA.toPrivateKey KeyPair
keyPair) Blake2b_256
Blake2b_256

-- | Check that a sequence of bytes has been signed with a given key.
checkSignature :: PublicKey -> Signature -> ByteString -> Bool
checkSignature :: PublicKey -> Signature -> ByteString -> Bool
checkSignature (PublicKey pk :: PublicKey
pk) (Signature sig :: Signature
sig) =
  Blake2b_256 -> PublicKey -> Signature -> ByteString -> Bool
forall msg hash.
(ByteArrayAccess msg, HashAlgorithm hash) =>
hash -> PublicKey -> Signature -> msg -> Bool
ECDSA.verify Blake2b_256
Blake2b_256 PublicKey
pk Signature
sig