From dce736e6bf72b5c866ca5a0fda877045c0520e6c Mon Sep 17 00:00:00 2001 From: Kevaundray Wedderburn Date: Mon, 14 Oct 2024 14:53:57 +0100 Subject: [PATCH] modify fuzzing --- tests/fuzzers/bn256/bn256_fuzz.go | 65 +++++++++++++++++-------------- 1 file changed, 35 insertions(+), 30 deletions(-) diff --git a/tests/fuzzers/bn256/bn256_fuzz.go b/tests/fuzzers/bn256/bn256_fuzz.go index 75f7d59dee..4383559dc0 100644 --- a/tests/fuzzers/bn256/bn256_fuzz.go +++ b/tests/fuzzers/bn256/bn256_fuzz.go @@ -22,12 +22,12 @@ import ( "io" "math/big" - "github.com/consensys/gnark-crypto/ecc/bn254" cloudflare "github.com/ethereum/go-ethereum/crypto/bn256/cloudflare" + gnark "github.com/ethereum/go-ethereum/crypto/bn256/gnark" google "github.com/ethereum/go-ethereum/crypto/bn256/google" ) -func getG1Points(input io.Reader) (*cloudflare.G1, *google.G1, *bn254.G1Affine) { +func getG1Points(input io.Reader) (*cloudflare.G1, *google.G1, *gnark.G1) { _, xc, err := cloudflare.RandomG1(input) if err != nil { // insufficient input @@ -37,14 +37,14 @@ func getG1Points(input io.Reader) (*cloudflare.G1, *google.G1, *bn254.G1Affine) if _, err := xg.Unmarshal(xc.Marshal()); err != nil { panic(fmt.Sprintf("Could not marshal cloudflare -> google: %v", err)) } - xs := new(bn254.G1Affine) - if err := xs.Unmarshal(xc.Marshal()); err != nil { + xs := new(gnark.G1) + if _, err := xs.Unmarshal(xc.Marshal()); err != nil { panic(fmt.Sprintf("Could not marshal cloudflare -> gnark: %v", err)) } return xc, xg, xs } -func getG2Points(input io.Reader) (*cloudflare.G2, *google.G2, *bn254.G2Affine) { +func getG2Points(input io.Reader) (*cloudflare.G2, *google.G2, *gnark.G2) { _, xc, err := cloudflare.RandomG2(input) if err != nil { // insufficient input @@ -54,14 +54,14 @@ func getG2Points(input io.Reader) (*cloudflare.G2, *google.G2, *bn254.G2Affine) if _, err := xg.Unmarshal(xc.Marshal()); err != nil { panic(fmt.Sprintf("Could not marshal cloudflare -> google: %v", err)) } - xs := new(bn254.G2Affine) - if err := xs.Unmarshal(xc.Marshal()); err != nil { + xs := new(gnark.G2) + if _, err := xs.Unmarshal(xc.Marshal()); err != nil { panic(fmt.Sprintf("Could not marshal cloudflare -> gnark: %v", err)) } return xc, xg, xs } -// fuzzAdd fuzzez bn256 addition between the Google and Cloudflare libraries. +// fuzzAdd fuzzes bn256 addition between the Google, Cloudflare and Gnark libraries. func fuzzAdd(data []byte) int { input := bytes.NewReader(data) xc, xg, xs := getG1Points(input) @@ -72,7 +72,7 @@ func fuzzAdd(data []byte) int { if yc == nil { return 0 } - // Ensure both libs can parse the second curve point + // Ensure libs can parse the second curve point // Add the two points and ensure they result in the same output rc := new(cloudflare.G1) rc.Add(xc, yc) @@ -80,9 +80,8 @@ func fuzzAdd(data []byte) int { rg := new(google.G1) rg.Add(xg, yg) - tmpX := new(bn254.G1Jac).FromAffine(xs) - tmpY := new(bn254.G1Jac).FromAffine(ys) - rs := new(bn254.G1Affine).FromJacobian(tmpX.AddAssign(tmpY)) + rs := new(gnark.G1) + rs.Add(xs, ys) if !bytes.Equal(rc.Marshal(), rg.Marshal()) { panic("add mismatch: cloudflare/google") @@ -94,8 +93,8 @@ func fuzzAdd(data []byte) int { return 1 } -// fuzzMul fuzzez bn256 scalar multiplication between the Google and Cloudflare -// libraries. +// fuzzMul fuzzes bn256 scalar multiplication between the Google, Cloudflare +// and Gnark libraries. func fuzzMul(data []byte) int { input := bytes.NewReader(data) pc, pg, ps := getG1Points(input) @@ -122,15 +121,13 @@ func fuzzMul(data []byte) int { rg := new(google.G1) rg.ScalarMult(pg, new(big.Int).SetBytes(buf)) - rs := new(bn254.G1Jac) - psJac := new(bn254.G1Jac).FromAffine(ps) - rs.ScalarMultiplication(psJac, new(big.Int).SetBytes(buf)) - rsAffine := new(bn254.G1Affine).FromJacobian(rs) + rs := new(gnark.G1) + rs.ScalarMult(ps, new(big.Int).SetBytes(buf)) if !bytes.Equal(rc.Marshal(), rg.Marshal()) { panic("scalar mul mismatch: cloudflare/google") } - if !bytes.Equal(rc.Marshal(), rsAffine.Marshal()) { + if !bytes.Equal(rc.Marshal(), rs.Marshal()) { panic("scalar mul mismatch: cloudflare/gnark") } return 1 @@ -150,17 +147,27 @@ func fuzzPair(data []byte) int { // Pair the two points and ensure they result in the same output clPair := cloudflare.Pair(pc, tc).Marshal() gPair := google.Pair(pg, tg).Marshal() + sPair := gnark.Pair(ps, ts).Marshal() + if !bytes.Equal(clPair, gPair) { panic("pairing mismatch: cloudflare/google") } - cPair, err := bn254.Pair([]bn254.G1Affine{*ps}, []bn254.G2Affine{*ts}) - if err != nil { - panic(fmt.Sprintf("gnark/bn254 encountered error: %v", err)) + + normalizedClPair := normalizeGTToGnark(clPair).Marshal() + if !bytes.Equal(normalizedClPair, sPair) { + panic("pairing mismatch: cloudflare/gnark") } - // gnark uses a different pairing algorithm which might produce - // different but also correct outputs, we need to scale the output by s + return 1 +} +// normalizeGTToGnark scales a Cloudflare/Google GT element by `s` +// so that it can be compared with a gnark GT point. +// +// For the definition of `s` see 3.5 in https://eprint.iacr.org/2015/192.pdf +func normalizeGTToGnark(cloudflareOrGoogleGT []byte) *gnark.GT { + + // Compute s = 2*u(6*u^2 + 3*u + 1) u, _ := new(big.Int).SetString("0x44e992b44a6909f1", 0) u_exp2 := new(big.Int).Exp(u, big.NewInt(2), nil) // u^2 u_6_exp2 := new(big.Int).Mul(big.NewInt(6), u_exp2) // 6*u^2 @@ -170,14 +177,12 @@ func fuzzPair(data []byte) int { u_2 := new(big.Int).Mul(big.NewInt(2), u) // 2*u s := u_2.Mul(u_2, inner) // 2*u(6*u^2 + 3*u + 1) - gRes := new(bn254.GT) - if err := gRes.SetBytes(clPair); err != nil { + // Scale the Cloudflare/Google GT element by `s` + gRes := new(gnark.GT) + if err := gRes.Unmarshal(cloudflareOrGoogleGT); err != nil { panic(err) } gRes = gRes.Exp(*gRes, s) - if !bytes.Equal(cPair.Marshal(), gRes.Marshal()) { - panic("pairing mismatch: cloudflare/gnark") - } - return 1 + return gRes }