From d46f69dc7a71e0f203a197064ed556a6f283d9e4 Mon Sep 17 00:00:00 2001 From: Marius van der Wijden Date: Tue, 16 May 2023 13:27:54 +0200 Subject: [PATCH] tests/fuzzers/bn256: add PairingCheck fuzzer (#27252) * tests/fuzzers/bn256: scale gnark result by constant * tests/fuzzers/bn256: scale gnark result by constant --- tests/fuzzers/bn256/bn256_fuzz.go | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/tests/fuzzers/bn256/bn256_fuzz.go b/tests/fuzzers/bn256/bn256_fuzz.go index 1ce20571f..abf1b8861 100644 --- a/tests/fuzzers/bn256/bn256_fuzz.go +++ b/tests/fuzzers/bn256/bn256_fuzz.go @@ -156,12 +156,29 @@ func FuzzPair(data []byte) int { 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)) } - if !bytes.Equal(clPair, cPair.Marshal()) { + + // gnark uses a different pairing algorithm which might produce + // different but also correct outputs, we need to scale the output by s + + 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 + u_3 := new(big.Int).Mul(big.NewInt(3), u) // 3*u + inner := u_6_exp2.Add(u_6_exp2, u_3) // 6*u^2 + 3*u + inner.Add(inner, big.NewInt(1)) // 6*u^2 + 3*u + 1 + 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 { + panic(err) + } + gRes = gRes.Exp(*gRes, s) + if !bytes.Equal(cPair.Marshal(), gRes.Marshal()) { panic("pairing mismatch: cloudflare/gnark") }