Official Go implementation of the Ethereum protocol
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go-ethereum/tests/fuzzers/bls12381/bls12381_fuzz.go

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11 KiB

// 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/>.
//go:build cgo
// +build cgo
package bls
import (
"bytes"
"crypto/rand"
"fmt"
"io"
"math/big"
"github.com/consensys/gnark-crypto/ecc"
gnark "github.com/consensys/gnark-crypto/ecc/bls12-381"
"github.com/consensys/gnark-crypto/ecc/bls12-381/fp"
"github.com/consensys/gnark-crypto/ecc/bls12-381/fr"
"github.com/ethereum/go-ethereum/common"
blst "github.com/supranational/blst/bindings/go"
)
func fuzzG1SubgroupChecks(data []byte) int {
input := bytes.NewReader(data)
cpG1, blG1, err := getG1Points(input)
if err != nil {
return 0
}
inSubGroupGnark := cpG1.IsInSubGroup()
inSubGroupBLST := blG1.InG1()
if inSubGroupGnark != inSubGroupBLST {
panic(fmt.Sprintf("differing subgroup check, gnark %v, blst %v", inSubGroupGnark, inSubGroupBLST))
}
return 1
}
func fuzzG2SubgroupChecks(data []byte) int {
input := bytes.NewReader(data)
gpG2, blG2, err := getG2Points(input)
if err != nil {
return 0
}
inSubGroupGnark := gpG2.IsInSubGroup()
inSubGroupBLST := blG2.InG2()
if inSubGroupGnark != inSubGroupBLST {
panic(fmt.Sprintf("differing subgroup check, gnark %v, blst %v", inSubGroupGnark, inSubGroupBLST))
}
return 1
}
func fuzzCrossPairing(data []byte) int {
input := bytes.NewReader(data)
// get random G1 points
cpG1, blG1, err := getG1Points(input)
if err != nil {
return 0
}
// get random G2 points
cpG2, blG2, err := getG2Points(input)
if err != nil {
return 0
}
// compute pairing using gnark
cResult, err := gnark.Pair([]gnark.G1Affine{*cpG1}, []gnark.G2Affine{*cpG2})
if err != nil {
panic(fmt.Sprintf("gnark/bls12381 encountered error: %v", err))
}
// compute pairing using blst
blstResult := blst.Fp12MillerLoop(blG2, blG1)
blstResult.FinalExp()
res := massageBLST(blstResult.ToBendian())
if !(bytes.Equal(res, cResult.Marshal())) {
panic("pairing mismatch blst / geth")
}
return 1
}
func massageBLST(in []byte) []byte {
out := make([]byte, len(in))
len := 12 * 48
// 1
copy(out[0:], in[len-1*48:len])
copy(out[1*48:], in[len-2*48:len-1*48])
// 2
copy(out[6*48:], in[len-3*48:len-2*48])
copy(out[7*48:], in[len-4*48:len-3*48])
// 3
copy(out[2*48:], in[len-5*48:len-4*48])
copy(out[3*48:], in[len-6*48:len-5*48])
// 4
copy(out[8*48:], in[len-7*48:len-6*48])
copy(out[9*48:], in[len-8*48:len-7*48])
// 5
copy(out[4*48:], in[len-9*48:len-8*48])
copy(out[5*48:], in[len-10*48:len-9*48])
// 6
copy(out[10*48:], in[len-11*48:len-10*48])
copy(out[11*48:], in[len-12*48:len-11*48])
return out
}
func fuzzCrossG1Add(data []byte) int {
input := bytes.NewReader(data)
// get random G1 points
cp1, bl1, err := getG1Points(input)
if err != nil {
return 0
}
// get random G1 points
cp2, bl2, err := getG1Points(input)
if err != nil {
return 0
}
// compute cp = cp1 + cp2
_cp1 := new(gnark.G1Jac).FromAffine(cp1)
_cp2 := new(gnark.G1Jac).FromAffine(cp2)
cp := new(gnark.G1Affine).FromJacobian(_cp1.AddAssign(_cp2))
bl3 := blst.P1AffinesAdd([]*blst.P1Affine{bl1, bl2})
if !(bytes.Equal(cp.Marshal(), bl3.Serialize())) {
panic("G1 point addition mismatch blst / geth ")
}
return 1
}
func fuzzCrossG2Add(data []byte) int {
input := bytes.NewReader(data)
// get random G2 points
gp1, bl1, err := getG2Points(input)
if err != nil {
return 0
}
// get random G2 points
gp2, bl2, err := getG2Points(input)
if err != nil {
return 0
}
// compute cp = cp1 + cp2
_gp1 := new(gnark.G2Jac).FromAffine(gp1)
_gp2 := new(gnark.G2Jac).FromAffine(gp2)
gp := new(gnark.G2Affine).FromJacobian(_gp1.AddAssign(_gp2))
bl3 := blst.P2AffinesAdd([]*blst.P2Affine{bl1, bl2})
if !(bytes.Equal(gp.Marshal(), bl3.Serialize())) {
panic("G1 point addition mismatch blst / geth ")
}
return 1
}
func fuzzCrossG1MultiExp(data []byte) int {
var (
input = bytes.NewReader(data)
gnarkScalars []fr.Element
gnarkPoints []gnark.G1Affine
blstScalars []*blst.Scalar
blstPoints []*blst.P1Affine
)
// n random scalars (max 17)
for i := 0; i < 17; i++ {
// note that geth/crypto/bls12381 works only with scalars <= 32bytes
s, err := randomScalar(input, fr.Modulus())
if err != nil {
break
}
// get a random G1 point as basis
cp1, bl1, err := getG1Points(input)
if err != nil {
break
}
gnarkScalar := new(fr.Element).SetBigInt(s)
gnarkScalars = append(gnarkScalars, *gnarkScalar)
gnarkPoints = append(gnarkPoints, *cp1)
blstScalar := new(blst.Scalar).FromBEndian(common.LeftPadBytes(s.Bytes(), 32))
blstScalars = append(blstScalars, blstScalar)
blstPoints = append(blstPoints, bl1)
}
if len(gnarkScalars) == 0 || len(gnarkScalars) != len(gnarkPoints) {
return 0
}
// gnark multi exp
cp := new(gnark.G1Affine)
cp.MultiExp(gnarkPoints, gnarkScalars, ecc.MultiExpConfig{})
expectedGnark := multiExpG1Gnark(gnarkPoints, gnarkScalars)
if !bytes.Equal(cp.Marshal(), expectedGnark.Marshal()) {
panic("g1 multi exponentiation mismatch")
}
// blst multi exp
expectedBlst := blst.P1AffinesMult(blstPoints, blstScalars, 256).ToAffine()
if !bytes.Equal(cp.Marshal(), expectedBlst.Serialize()) {
panic("g1 multi exponentiation mismatch, gnark/blst")
}
return 1
}
func fuzzCrossG1Mul(data []byte) int {
input := bytes.NewReader(data)
gp, blpAffine, err := getG1Points(input)
if err != nil {
return 0
}
scalar, err := randomScalar(input, fp.Modulus())
if err != nil {
return 0
}
blScalar := new(blst.Scalar).FromBEndian(common.LeftPadBytes(scalar.Bytes(), 32))
blp := new(blst.P1)
blp.FromAffine(blpAffine)
resBl := blp.Mult(blScalar)
resGeth := (new(gnark.G1Affine)).ScalarMultiplication(gp, scalar)
if !bytes.Equal(resGeth.Marshal(), resBl.Serialize()) {
panic("bytes(blst.G1) != bytes(geth.G1)")
}
return 1
}
func fuzzCrossG2Mul(data []byte) int {
input := bytes.NewReader(data)
gp, blpAffine, err := getG2Points(input)
if err != nil {
return 0
}
scalar, err := randomScalar(input, fp.Modulus())
if err != nil {
return 0
}
blScalar := new(blst.Scalar).FromBEndian(common.LeftPadBytes(scalar.Bytes(), 32))
blp := new(blst.P2)
blp.FromAffine(blpAffine)
resBl := blp.Mult(blScalar)
resGeth := (new(gnark.G2Affine)).ScalarMultiplication(gp, scalar)
if !bytes.Equal(resGeth.Marshal(), resBl.Serialize()) {
panic("bytes(blst.G1) != bytes(geth.G1)")
}
return 1
}
func fuzzCrossG2MultiExp(data []byte) int {
var (
input = bytes.NewReader(data)
gnarkScalars []fr.Element
gnarkPoints []gnark.G2Affine
blstScalars []*blst.Scalar
blstPoints []*blst.P2Affine
)
// n random scalars (max 17)
for i := 0; i < 17; i++ {
// note that geth/crypto/bls12381 works only with scalars <= 32bytes
s, err := randomScalar(input, fr.Modulus())
if err != nil {
break
}
// get a random G1 point as basis
cp1, bl1, err := getG2Points(input)
if err != nil {
break
}
gnarkScalar := new(fr.Element).SetBigInt(s)
gnarkScalars = append(gnarkScalars, *gnarkScalar)
gnarkPoints = append(gnarkPoints, *cp1)
blstScalar := new(blst.Scalar).FromBEndian(common.LeftPadBytes(s.Bytes(), 32))
blstScalars = append(blstScalars, blstScalar)
blstPoints = append(blstPoints, bl1)
}
if len(gnarkScalars) == 0 || len(gnarkScalars) != len(gnarkPoints) {
return 0
}
// gnark multi exp
cp := new(gnark.G2Affine)
cp.MultiExp(gnarkPoints, gnarkScalars, ecc.MultiExpConfig{})
expectedGnark := multiExpG2Gnark(gnarkPoints, gnarkScalars)
if !bytes.Equal(cp.Marshal(), expectedGnark.Marshal()) {
panic("g1 multi exponentiation mismatch")
}
// blst multi exp
expectedBlst := blst.P2AffinesMult(blstPoints, blstScalars, 256).ToAffine()
if !bytes.Equal(cp.Marshal(), expectedBlst.Serialize()) {
panic("g1 multi exponentiation mismatch, gnark/blst")
}
return 1
}
func getG1Points(input io.Reader) (*gnark.G1Affine, *blst.P1Affine, error) {
// sample a random scalar
s, err := randomScalar(input, fp.Modulus())
if err != nil {
return nil, nil, err
}
// compute a random point
cp := new(gnark.G1Affine)
_, _, g1Gen, _ := gnark.Generators()
cp.ScalarMultiplication(&g1Gen, s)
cpBytes := cp.Marshal()
// marshal gnark point -> blst point
scalar := new(blst.Scalar).FromBEndian(common.LeftPadBytes(s.Bytes(), 32))
p1 := new(blst.P1Affine).From(scalar)
blstRes := p1.Serialize()
if !bytes.Equal(blstRes, cpBytes) {
panic(fmt.Sprintf("bytes(blst.G1) != bytes(geth.G1)\nblst.G1: %x\ngeth.G1: %x\n", blstRes, cpBytes))
}
return cp, p1, nil
}
func getG2Points(input io.Reader) (*gnark.G2Affine, *blst.P2Affine, error) {
// sample a random scalar
s, err := randomScalar(input, fp.Modulus())
if err != nil {
return nil, nil, err
}
// compute a random point
gp := new(gnark.G2Affine)
_, _, _, g2Gen := gnark.Generators()
gp.ScalarMultiplication(&g2Gen, s)
cpBytes := gp.Marshal()
// marshal gnark point -> blst point
// Left pad the scalar to 32 bytes
scalar := new(blst.Scalar).FromBEndian(common.LeftPadBytes(s.Bytes(), 32))
p2 := new(blst.P2Affine).From(scalar)
if !bytes.Equal(p2.Serialize(), cpBytes) {
panic("bytes(blst.G2) != bytes(bls12381.G2)")
}
return gp, p2, nil
}
func randomScalar(r io.Reader, max *big.Int) (k *big.Int, err error) {
for {
k, err = rand.Int(r, max)
if err != nil || k.Sign() > 0 {
return
}
}
}
// multiExpG1Gnark is a naive implementation of G1 multi-exponentiation
func multiExpG1Gnark(gs []gnark.G1Affine, scalars []fr.Element) gnark.G1Affine {
res := gnark.G1Affine{}
for i := 0; i < len(gs); i++ {
tmp := new(gnark.G1Affine)
sb := scalars[i].Bytes()
scalarBytes := new(big.Int).SetBytes(sb[:])
tmp.ScalarMultiplication(&gs[i], scalarBytes)
res.Add(&res, tmp)
}
return res
}
// multiExpG1Gnark is a naive implementation of G1 multi-exponentiation
func multiExpG2Gnark(gs []gnark.G2Affine, scalars []fr.Element) gnark.G2Affine {
res := gnark.G2Affine{}
for i := 0; i < len(gs); i++ {
tmp := new(gnark.G2Affine)
sb := scalars[i].Bytes()
scalarBytes := new(big.Int).SetBytes(sb[:])
tmp.ScalarMultiplication(&gs[i], scalarBytes)
res.Add(&res, tmp)
}
return res
}