feat: remove btcd dependency

crypto/signature_nocgo.go

@@ -14,65 +14,85 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
 
-//go:build nacl || js || !cgo || gofuzz
-// +build nacl js !cgo gofuzz
+//go:build nacl || js || wasip1 || !cgo || gofuzz || tinygo
+// +build nacl js wasip1 !cgo gofuzz tinygo
 
 package crypto
 
 import (
 	"crypto/ecdsa"
-	"crypto/elliptic"
 	"errors"
 	"fmt"
 	"math/big"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/decred/dcrd/dcrec/secp256k1/v4"
+	decred_ecdsa "github.com/decred/dcrd/dcrec/secp256k1/v4/ecdsa"
 )
 
 // Ecrecover returns the uncompressed public key that created the given signature.
 func Ecrecover(hash, sig []byte) ([]byte, error) {
-	pub, err := SigToPub(hash, sig)
+	pub, err := sigToPub(hash, sig)
 	if err != nil {
 		return nil, err
 	}
-	bytes := (*btcec.PublicKey)(pub).SerializeUncompressed()
+	bytes := pub.SerializeUncompressed()
 	return bytes, err
 }
 
-// SigToPub returns the public key that created the given signature.
-func SigToPub(hash, sig []byte) (*ecdsa.PublicKey, error) {
-	// Convert to btcec input format with 'recovery id' v at the beginning.
+func sigToPub(hash, sig []byte) (*secp256k1.PublicKey, error) {
+	if len(sig) != SignatureLength {
+		return nil, errors.New("invalid signature")
+	}
+	// Convert to secp256k1 input format with 'recovery id' v at the beginning.
 	btcsig := make([]byte, SignatureLength)
-	btcsig[0] = sig[64] + 27
+	btcsig[0] = sig[RecoveryIDOffset] + 27
 	copy(btcsig[1:], sig)
 
-	pub, _, err := btcec.RecoverCompact(btcec.S256(), btcsig, hash)
-	return (*ecdsa.PublicKey)(pub), err
+	pub, _, err := decred_ecdsa.RecoverCompact(btcsig, hash)
+	return pub, err
+}
+
+// SigToPub returns the public key that created the given signature.
+func SigToPub(hash, sig []byte) (*ecdsa.PublicKey, error) {
+	pub, err := sigToPub(hash, sig)
+	if err != nil {
+		return nil, err
+	}
+	// We need to explicitly set the curve here, because we're wrapping
+	// the original curve to add (un-)marshalling
+	return &ecdsa.PublicKey{
+		Curve: S256(),
+		X:     pub.X(),
+		Y:     pub.Y(),
+	}, nil
 }
 
 // Sign calculates an ECDSA signature.
 //
 // This function is susceptible to chosen plaintext attacks that can leak
 // information about the private key that is used for signing. Callers must
-// be aware that the given hash cannot be chosen by an adversery. Common
+// be aware that the given hash cannot be chosen by an adversary. Common
 // solution is to hash any input before calculating the signature.
 //
 // The produced signature is in the [R || S || V] format where V is 0 or 1.
 func Sign(hash []byte, prv *ecdsa.PrivateKey) ([]byte, error) {
 	if len(hash) != 32 {
 		return nil, fmt.Errorf("hash is required to be exactly 32 bytes (%d)", len(hash))
 	}
-	if prv.Curve != btcec.S256() {
-		return nil, fmt.Errorf("private key curve is not secp256k1")
+	if prv.Curve != S256() {
+		return nil, errors.New("private key curve is not secp256k1")
 	}
-	sig, err := btcec.SignCompact(btcec.S256(), (*btcec.PrivateKey)(prv), hash, false)
-	if err != nil {
-		return nil, err
+	// ecdsa.PrivateKey -> secp256k1.PrivateKey
+	var priv secp256k1.PrivateKey
+	if overflow := priv.Key.SetByteSlice(prv.D.Bytes()); overflow || priv.Key.IsZero() {
+		return nil, errors.New("invalid private key")
 	}
+	defer priv.Zero()
+	sig := decred_ecdsa.SignCompact(&priv, hash, false) // ref uncompressed pubkey
 	// Convert to Ethereum signature format with 'recovery id' v at the end.
 	v := sig[0] - 27
 	copy(sig, sig[1:])
-	sig[64] = v
+	sig[RecoveryIDOffset] = v
 	return sig, nil
 }
 
@@ -83,13 +103,20 @@ func VerifySignature(pubkey, hash, signature []byte) bool {
 	if len(signature) != 64 {
 		return false
 	}
-	sig := &btcec.Signature{R: new(big.Int).SetBytes(signature[:32]), S: new(big.Int).SetBytes(signature[32:])}
-	key, err := btcec.ParsePubKey(pubkey, btcec.S256())
+	var r, s secp256k1.ModNScalar
+	if r.SetByteSlice(signature[:32]) {
+		return false // overflow
+	}
+	if s.SetByteSlice(signature[32:]) {
+		return false
+	}
+	sig := decred_ecdsa.NewSignature(&r, &s)
+	key, err := secp256k1.ParsePubKey(pubkey)
 	if err != nil {
 		return false
 	}
-	// Reject malleable signatures. libsecp256k1 does this check but btcec doesn't.
-	if sig.S.Cmp(secp256k1halfN) > 0 {
+	// Reject malleable signatures. libsecp256k1 does this check but decred doesn't.
+	if s.IsOverHalfOrder() {
 		return false
 	}
 	return sig.Verify(hash, key)
@@ -100,19 +127,67 @@ func DecompressPubkey(pubkey []byte) (*ecdsa.PublicKey, error) {
 	if len(pubkey) != 33 {
 		return nil, errors.New("invalid compressed public key length")
 	}
-	key, err := btcec.ParsePubKey(pubkey, btcec.S256())
+	key, err := secp256k1.ParsePubKey(pubkey)
 	if err != nil {
 		return nil, err
 	}
-	return key.ToECDSA(), nil
+	// We need to explicitly set the curve here, because we're wrapping
+	// the original curve to add (un-)marshalling
+	return &ecdsa.PublicKey{
+		Curve: S256(),
+		X:     key.X(),
+		Y:     key.Y(),
+	}, nil
 }
 
-// CompressPubkey encodes a public key to the 33-byte compressed format.
+// CompressPubkey encodes a public key to the 33-byte compressed format. The
+// provided PublicKey must be valid. Namely, the coordinates must not be larger
+// than 32 bytes each, they must be less than the field prime, and it must be a
+// point on the secp256k1 curve. This is the case for a PublicKey constructed by
+// elliptic.Unmarshal (see UnmarshalPubkey), or by ToECDSA and ecdsa.GenerateKey
+// when constructing a PrivateKey.
 func CompressPubkey(pubkey *ecdsa.PublicKey) []byte {
-	return (*btcec.PublicKey)(pubkey).SerializeCompressed()
+	// NOTE: the coordinates may be validated with
+	// secp256k1.ParsePubKey(FromECDSAPub(pubkey))
+	var x, y secp256k1.FieldVal
+	x.SetByteSlice(pubkey.X.Bytes())
+	y.SetByteSlice(pubkey.Y.Bytes())
+	return secp256k1.NewPublicKey(&x, &y).SerializeCompressed()
 }
 
 // S256 returns an instance of the secp256k1 curve.
-func S256() elliptic.Curve {
-	return btcec.S256()
+func S256() EllipticCurve {
+	return btCurve{secp256k1.S256()}
+}
+
+type btCurve struct {
+	*secp256k1.KoblitzCurve
+}
+
+// Marshal converts a point given as (x, y) into a byte slice.
+func (curve btCurve) Marshal(x, y *big.Int) []byte {
+	byteLen := (curve.Params().BitSize + 7) / 8
+
+	ret := make([]byte, 1+2*byteLen)
+	ret[0] = 4 // uncompressed point
+
+	x.FillBytes(ret[1 : 1+byteLen])
+	y.FillBytes(ret[1+byteLen : 1+2*byteLen])
+
+	return ret
+}
+
+// Unmarshal converts a point, serialised by Marshal, into an x, y pair. On
+// error, x = nil.
+func (curve btCurve) Unmarshal(data []byte) (x, y *big.Int) {
+	byteLen := (curve.Params().BitSize + 7) / 8
+	if len(data) != 1+2*byteLen {
+		return nil, nil
+	}
+	if data[0] != 4 { // uncompressed form
+		return nil, nil
+	}
+	x = new(big.Int).SetBytes(data[1 : 1+byteLen])
+	y = new(big.Int).SetBytes(data[1+byteLen:])
+	return
 }

go.mod

@@ -17,6 +17,7 @@ require (
 	github.com/crate-crypto/go-kzg-4844 v1.0.0
 	github.com/davecgh/go-spew v1.1.1
 	github.com/deckarep/golang-set v0.0.0-20180603214616-504e848d77ea
+	github.com/decred/dcrd/dcrec/secp256k1/v4 v4.4.0
 	github.com/docker/docker v1.4.2-0.20180625184442-8e610b2b55bf
 	github.com/dop251/goja v0.0.0-20211011172007-d99e4b8cbf48
 	github.com/edsrzf/mmap-go v1.0.0

go.sum

@@ -112,6 +112,10 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/deckarep/golang-set v0.0.0-20180603214616-504e848d77ea h1:j4317fAZh7X6GqbFowYdYdI0L9bwxL07jyPZIdepyZ0=
 github.com/deckarep/golang-set v0.0.0-20180603214616-504e848d77ea/go.mod h1:93vsz/8Wt4joVM7c2AVqh+YRMiUSc14yDtF28KmMOgQ=
+github.com/decred/dcrd/crypto/blake256 v1.1.0 h1:zPMNGQCm0g4QTY27fOCorQW7EryeQ/U0x++OzVrdms8=
+github.com/decred/dcrd/crypto/blake256 v1.1.0/go.mod h1:2OfgNZ5wDpcsFmHmCK5gZTPcCXqlm2ArzUIkw9czNJo=
+github.com/decred/dcrd/dcrec/secp256k1/v4 v4.4.0 h1:NMZiJj8QnKe1LgsbDayM4UoHwbvwDRwnI3hwNaAHRnc=
+github.com/decred/dcrd/dcrec/secp256k1/v4 v4.4.0/go.mod h1:ZXNYxsqcloTdSy/rNShjYzMhyjf0LaoftYK0p+A3h40=
 github.com/deepmap/oapi-codegen v1.6.0/go.mod h1:ryDa9AgbELGeB+YEXE1dR53yAjHwFvE9iAUlWl9Al3M=
 github.com/deepmap/oapi-codegen v1.8.2 h1:SegyeYGcdi0jLLrpbCMoJxnUUn8GBXHsvr4rbzjuhfU=
 github.com/deepmap/oapi-codegen v1.8.2/go.mod h1:YLgSKSDv/bZQB7N4ws6luhozi3cEdRktEqrX88CvjIw=

tests/fuzzers/secp256k1/secp_test.go

@@ -1,8 +1,53 @@
+// Copyright 2021 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
 package secp256k1
 
-import "testing"
+import (
+	"fmt"
+	"testing"
+
+	dcred_secp256k1 "github.com/decred/dcrd/dcrec/secp256k1/v4"
+	"github.com/scroll-tech/go-ethereum/crypto/secp256k1"
+)
 
 func TestFuzzer(t *testing.T) {
-	test := "00000000N0000000/R00000000000000000U0000S0000000mkhP000000000000000U"
-	Fuzz([]byte(test))
+	a, b := "00000000N0000000/R0000000000000000", "0U0000S0000000mkhP000000000000000U"
+	fuzz([]byte(a), []byte(b))
+}
+
+func Fuzz(f *testing.F) {
+	f.Fuzz(func(t *testing.T, a, b []byte) {
+		fuzz(a, b)
+	})
+}
+
+func fuzz(dataP1, dataP2 []byte) {
+	var (
+		curveA = secp256k1.S256()
+		curveB = dcred_secp256k1.S256()
+	)
+	// first point
+	x1, y1 := curveB.ScalarBaseMult(dataP1)
+	// second points
+	x2, y2 := curveB.ScalarBaseMult(dataP2)
+	resAX, resAY := curveA.Add(x1, y1, x2, y2)
+	resBX, resBY := curveB.Add(x1, y1, x2, y2)
+	if resAX.Cmp(resBX) != 0 || resAY.Cmp(resBY) != 0 {
+		fmt.Printf("%s %s %s %s\n", x1, y1, x2, y2)
+		panic(fmt.Sprintf("Addition failed: geth: %s %s btcd: %s %s", resAX, resAY, resBX, resBY))
+	}
 }