chore(deps, crypto): use secp directly instead of wrapper

crypto/hd/hdpath.go

@@ -10,7 +10,7 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/btcsuite/btcd/btcec"
+	secp "github.com/decred/dcrd/dcrec/secp256k1/v4"
 )
 
 // BIP44Params wraps BIP 44 params (5 level BIP 32 path).
@@ -237,7 +237,7 @@ func derivePrivateKey(privKeyBytes [32]byte, chainCode [32]byte, index uint32, h
 		data = append([]byte{byte(0)}, privKeyBytes[:]...)
 	} else {
 		// this can't return an error:
-		_, ecPub := btcec.PrivKeyFromBytes(btcec.S256(), privKeyBytes[:])
+		ecPub := secp.PrivKeyFromBytes(privKeyBytes[:]).PubKey()
 		pubkeyBytes := ecPub.SerializeCompressed()
 		data = pubkeyBytes
 
@@ -260,7 +260,7 @@ func addScalars(a []byte, b []byte) [32]byte {
 	aInt := new(big.Int).SetBytes(a)
 	bInt := new(big.Int).SetBytes(b)
 	sInt := new(big.Int).Add(aInt, bInt)
-	x := sInt.Mod(sInt, btcec.S256().N).Bytes()
+	x := sInt.Mod(sInt, secp.S256().N).Bytes()
 	x2 := [32]byte{}
 	copy(x2[32-len(x):], x)
 

crypto/keys/secp256k1/secp256k1.go

@@ -8,7 +8,7 @@ import (
 	"io"
 	"math/big"
 
-	secp256k1 "github.com/btcsuite/btcd/btcec"
+	"github.com/decred/dcrd/dcrec/secp256k1/v4"
 	"golang.org/x/crypto/ripemd160" //nolint: staticcheck // necessary for Bitcoin address format
 
 	"github.com/Finschia/ostracon/crypto"
@@ -38,7 +38,7 @@ func (privKey *PrivKey) Bytes() []byte {
 // PubKey performs the point-scalar multiplication from the privKey on the
 // generator point to get the pubkey.
 func (privKey *PrivKey) PubKey() cryptotypes.PubKey {
-	_, pubkeyObject := secp256k1.PrivKeyFromBytes(secp256k1.S256(), privKey.Key)
+	pubkeyObject := secp256k1.PrivKeyFromBytes(privKey.Key).PubKey()
 	pk := pubkeyObject.SerializeCompressed()
 	return &PubKey{Key: pk}
 }

crypto/keys/secp256k1/secp256k1_internal_test.go

@@ -5,7 +5,7 @@ import (
 	"math/big"
 	"testing"
 
-	btcSecp256k1 "github.com/btcsuite/btcd/btcec"
+	secp "github.com/decred/dcrd/dcrec/secp256k1/v4"
 	"github.com/stretchr/testify/require"
 )
 
@@ -23,7 +23,7 @@ func Test_genPrivKey(t *testing.T) {
 		shouldPanic bool
 	}{
 		{"empty bytes (panics because 1st 32 bytes are zero and 0 is not a valid field element)", empty, true},
-		{"curve order: N", btcSecp256k1.S256().N.Bytes(), true},
+		{"curve order: N", secp.S256().N.Bytes(), true},
 		{"valid because 0 < 1 < N", validOne, false},
 	}
 	for _, tt := range tests {
@@ -37,7 +37,7 @@ func Test_genPrivKey(t *testing.T) {
 			}
 			got := genPrivKey(bytes.NewReader(tt.notSoRand))
 			fe := new(big.Int).SetBytes(got[:])
-			require.True(t, fe.Cmp(btcSecp256k1.S256().N) < 0)
+			require.True(t, fe.Cmp(secp.S256().N) < 0)
 			require.True(t, fe.Sign() > 0)
 		})
 	}

crypto/keys/secp256k1/secp256k1_nocgo.go

@@ -4,29 +4,22 @@
 package secp256k1
 
 import (
-	"math/big"
+	"errors"
 
-	secp256k1 "github.com/btcsuite/btcd/btcec"
+	"github.com/decred/dcrd/dcrec/secp256k1/v4"
+	"github.com/decred/dcrd/dcrec/secp256k1/v4/ecdsa"
 
 	"github.com/Finschia/ostracon/crypto"
 )
 
-// used to reject malleable signatures
-// see:
-//   - https://github.com/ethereum/go-ethereum/blob/f9401ae011ddf7f8d2d95020b7446c17f8d98dc1/crypto/signature_nocgo.go#L90-L93
-//   - https://github.com/ethereum/go-ethereum/blob/f9401ae011ddf7f8d2d95020b7446c17f8d98dc1/crypto/crypto.go#L39
-var secp256k1halfN = new(big.Int).Rsh(secp256k1.S256().N, 1)
-
 // Sign creates an ECDSA signature on curve Secp256k1, using SHA256 on the msg.
 // The returned signature will be of the form R || S (in lower-S form).
 func (privKey *PrivKey) Sign(msg []byte) ([]byte, error) {
-	priv, _ := secp256k1.PrivKeyFromBytes(secp256k1.S256(), privKey.Key)
-	sig, err := priv.Sign(crypto.Sha256(msg))
-	if err != nil {
-		return nil, err
-	}
-	sigBytes := serializeSig(sig)
-	return sigBytes, nil
+	priv := secp256k1.PrivKeyFromBytes(privKey.Key)
+	sig := ecdsa.SignCompact(priv, crypto.Sha256(msg), false)
+
+	// remove the first byte which is compactSigRecoveryCode
+	return sig[1:], nil
 }
 
 // VerifyBytes verifies a signature of the form R || S.
@@ -35,37 +28,29 @@ func (pubKey *PubKey) VerifySignature(msg []byte, sigStr []byte) bool {
 	if len(sigStr) != 64 {
 		return false
 	}
-	pub, err := secp256k1.ParsePubKey(pubKey.Key, secp256k1.S256())
+	pub, err := secp256k1.ParsePubKey(pubKey.Key)
 	if err != nil {
 		return false
 	}
-	// parse the signature:
-	signature := signatureFromBytes(sigStr)
-	// Reject malleable signatures. libsecp256k1 does this check but btcec doesn't.
-	// see: https://github.com/ethereum/go-ethereum/blob/f9401ae011ddf7f8d2d95020b7446c17f8d98dc1/crypto/signature_nocgo.go#L90-L93
-	if signature.S.Cmp(secp256k1halfN) > 0 {
+	// parse the signature, will return error if it is not in lower-S form
+	signature, err := signatureFromBytes(sigStr)
+	if err != nil {
 		return false
 	}
 	return signature.Verify(crypto.Sha256(msg), pub)
 }
 
 // Read Signature struct from R || S. Caller needs to ensure
 // that len(sigStr) == 64.
-func signatureFromBytes(sigStr []byte) *secp256k1.Signature {
-	return &secp256k1.Signature{
-		R: new(big.Int).SetBytes(sigStr[:32]),
-		S: new(big.Int).SetBytes(sigStr[32:64]),
+// Rejects malleable signatures (if S value if it is over half order).
+func signatureFromBytes(sigStr []byte) (*ecdsa.Signature, error) {
+	var r secp256k1.ModNScalar
+	r.SetByteSlice(sigStr[:32])
+	var s secp256k1.ModNScalar
+	s.SetByteSlice(sigStr[32:64])
+	if s.IsOverHalfOrder() {
+		return nil, errors.New("signature is not in lower-S form")
 	}
-}
 
-// Serialize signature to R || S.
-// R, S are padded to 32 bytes respectively.
-func serializeSig(sig *secp256k1.Signature) []byte {
-	rBytes := sig.R.Bytes()
-	sBytes := sig.S.Bytes()
-	sigBytes := make([]byte, 64)
-	// 0 pad the byte arrays from the left if they aren't big enough.
-	copy(sigBytes[32-len(rBytes):32], rBytes)
-	copy(sigBytes[64-len(sBytes):64], sBytes)
-	return sigBytes
+	return ecdsa.NewSignature(&r, &s), nil
 }

crypto/keys/secp256k1/secp256k1_nocgo_test.go

@@ -6,7 +6,7 @@ package secp256k1
 import (
 	"testing"
 
-	secp256k1 "github.com/btcsuite/btcd/btcec"
+	"github.com/decred/dcrd/dcrec/secp256k1/v4"
 	"github.com/stretchr/testify/require"
 )
 
@@ -19,20 +19,30 @@ func TestSignatureVerificationAndRejectUpperS(t *testing.T) {
 		priv := GenPrivKey()
 		sigStr, err := priv.Sign(msg)
 		require.NoError(t, err)
-		sig := signatureFromBytes(sigStr)
-		require.False(t, sig.S.Cmp(secp256k1halfN) > 0)
+		var r secp256k1.ModNScalar
+		r.SetByteSlice(sigStr[:32])
+		var s secp256k1.ModNScalar
+		s.SetByteSlice(sigStr[32:64])
+		require.False(t, s.IsOverHalfOrder())
 
 		pub := priv.PubKey()
 		require.True(t, pub.VerifySignature(msg, sigStr))
 
 		// malleate:
-		sig.S.Sub(secp256k1.S256().CurveParams.N, sig.S)
-		require.True(t, sig.S.Cmp(secp256k1halfN) > 0)
-		malSigStr := serializeSig(sig)
+		var S256 secp256k1.ModNScalar
+		S256.SetByteSlice(secp256k1.S256().N.Bytes())
+		s.Negate().Add(&S256)
+		require.True(t, s.IsOverHalfOrder())
+
+		rBytes := r.Bytes()
+		sBytes := s.Bytes()
+		malSigStr := make([]byte, 64)
+		copy(malSigStr[32-len(rBytes):32], rBytes[:])
+		copy(malSigStr[64-len(sBytes):64], sBytes[:])
 
 		require.False(t, pub.VerifySignature(msg, malSigStr),
 			"VerifyBytes incorrect with malleated & invalid S. sig=%v, key=%v",
-			sig,
+			malSigStr,
 			priv,
 		)
 	}