path: root/crypto/bn256/bn256_fuzz.go

// Copyright 2018 Péter Szilágyi. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be found
// in the LICENSE file.

// +build gofuzz

package bn256

import (
    "bytes"
    "math/big"

    cloudflare "github.com/dexon-foundation/dexon/crypto/bn256/cloudflare"
    google "github.com/dexon-foundation/dexon/crypto/bn256/google"
)

// FuzzAdd fuzzez bn256 addition between the Google and Cloudflare libraries.
func FuzzAdd(data []byte) int {
    // Ensure we have enough data in the first place
    if len(data) != 128 {
        return 0
    }
    // Ensure both libs can parse the first curve point
    xc := new(cloudflare.G1)
    _, errc := xc.Unmarshal(data[:64])

    xg := new(google.G1)
    _, errg := xg.Unmarshal(data[:64])

    if (errc == nil) != (errg == nil) {
        panic("parse mismatch")
    } else if errc != nil {
        return 0
    }
    // Ensure both libs can parse the second curve point
    yc := new(cloudflare.G1)
    _, errc = yc.Unmarshal(data[64:])

    yg := new(google.G1)
    _, errg = yg.Unmarshal(data[64:])

    if (errc == nil) != (errg == nil) {
        panic("parse mismatch")
    } else if errc != nil {
        return 0
    }
    // Add the two points and ensure they result in the same output
    rc := new(cloudflare.G1)
    rc.Add(xc, yc)

    rg := new(google.G1)
    rg.Add(xg, yg)

    if !bytes.Equal(rc.Marshal(), rg.Marshal()) {
        panic("add mismatch")
    }
    return 0
}

// FuzzMul fuzzez bn256 scalar multiplication between the Google and Cloudflare
// libraries.
func FuzzMul(data []byte) int {
    // Ensure we have enough data in the first place
    if len(data) != 96 {
        return 0
    }
    // Ensure both libs can parse the curve point
    pc := new(cloudflare.G1)
    _, errc := pc.Unmarshal(data[:64])

    pg := new(google.G1)
    _, errg := pg.Unmarshal(data[:64])

    if (errc == nil) != (errg == nil) {
        panic("parse mismatch")
    } else if errc != nil {
        return 0
    }
    // Add the two points and ensure they result in the same output
    rc := new(cloudflare.G1)
    rc.ScalarMult(pc, new(big.Int).SetBytes(data[64:]))

    rg := new(google.G1)
    rg.ScalarMult(pg, new(big.Int).SetBytes(data[64:]))

    if !bytes.Equal(rc.Marshal(), rg.Marshal()) {
        panic("scalar mul mismatch")
    }
    return 0
}

func FuzzPair(data []byte) int {
    // Ensure we have enough data in the first place
    if len(data) != 192 {
        return 0
    }
    // Ensure both libs can parse the curve point
    pc := new(cloudflare.G1)
    _, errc := pc.Unmarshal(data[:64])

    pg := new(google.G1)
    _, errg := pg.Unmarshal(data[:64])

    if (errc == nil) != (errg == nil) {
        panic("parse mismatch")
    } else if errc != nil {
        return 0
    }
    // Ensure both libs can parse the twist point
    tc := new(cloudflare.G2)
    _, errc = tc.Unmarshal(data[64:])

    tg := new(google.G2)
    _, errg = tg.Unmarshal(data[64:])

    if (errc == nil) != (errg == nil) {
        panic("parse mismatch")
    } else if errc != nil {
        return 0
    }
    // Pair the two points and ensure thet result in the same output
    if cloudflare.PairingCheck([]*cloudflare.G1{pc}, []*cloudflare.G2{tc}) != google.PairingCheck([]*google.G1{pg}, []*google.G2{tg}) {
        panic("pair mismatch")
    }
    return 0
}