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Prevents subverted CRS attack on deltas #11

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Prevents subverted CRS attack on deltas #11

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5 changes: 4 additions & 1 deletion build/websnark_bn128.js
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Original file line number Diff line number Diff line change
Expand Up @@ -5534,7 +5534,7 @@ class Bn128 {
}, [signals, polsA, polsB]);
}

async groth16GenProof(signals, pkey) {
async groth16GenProof(signals, pkey, allowDetlaZero) {
const pkey32 = new Uint32Array(pkey);
const nSignals = pkey32[0];
const nPublic = pkey32[1];
Expand All @@ -5560,6 +5560,9 @@ class Bn128 {
const beta2 = pkey.slice(10*4 + 192, 10*4 + 320);
const delta2 = pkey.slice(10*4 + 320, 10*4 + 448);

if (!allowDeltaZero && ((this.instance.exports.g1m_isZero(delta1) == 1) || (this.instance.exports.g1m_isZero(delta2) == 1))) {
throw new Error('delta1 or delta2 are zero, subverted CRS');
}

const pH = this.calcH(signals.slice(0), polsA, polsB, nSignals, domainSize).then( (h) => {
/* Debug code to print the result of h
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5 changes: 4 additions & 1 deletion example/bn128/websnark_bn128.js
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Original file line number Diff line number Diff line change
Expand Up @@ -5534,7 +5534,7 @@ class Bn128 {
}, [signals, polsA, polsB]);
}

async groth16GenProof(signals, pkey) {
async groth16GenProof(signals, pkey, allowDetlaZero) {
const pkey32 = new Uint32Array(pkey);
const nSignals = pkey32[0];
const nPublic = pkey32[1];
Expand All @@ -5560,6 +5560,9 @@ class Bn128 {
const beta2 = pkey.slice(10*4 + 192, 10*4 + 320);
const delta2 = pkey.slice(10*4 + 320, 10*4 + 448);

if (!allowDeltaZero && ((this.instance.exports.g1m_isZero(delta1) == 1) || (this.instance.exports.g1m_isZero(delta2) == 1))) {
throw new Error('delta1 or delta2 are zero, subverted CRS');
}

const pH = this.calcH(signals.slice(0), polsA, polsB, nSignals, domainSize).then( (h) => {
/* Debug code to print the result of h
Expand Down
5 changes: 4 additions & 1 deletion src/bn128.js
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Original file line number Diff line number Diff line change
Expand Up @@ -578,7 +578,7 @@ class Bn128 {
}, [signals, polsA, polsB]);
}

async groth16GenProof(signals, pkey) {
async groth16GenProof(signals, pkey, allowDeltaZero) {
const pkey32 = new Uint32Array(pkey);
const nSignals = pkey32[0];
const nPublic = pkey32[1];
Expand All @@ -604,6 +604,9 @@ class Bn128 {
const beta2 = pkey.slice(10*4 + 192, 10*4 + 320);
const delta2 = pkey.slice(10*4 + 320, 10*4 + 448);

if (!allowDeltaZero && ((this.instance.exports.g1m_isZero(delta1) == 1) || (this.instance.exports.g1m_isZero(delta2) == 1))) {
throw new Error('delta1 or delta2 are zero, subverted CRS');
}

const pH = this.calcH(signals.slice(0), polsA, polsB, nSignals, domainSize).then( (h) => {
/* Debug code to print the result of h
Expand Down
2 changes: 1 addition & 1 deletion test/bn128_prover.js
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Expand Up @@ -54,7 +54,7 @@ describe("Basic tests for bn128 proof generator", () => {

const signals = fs.readFileSync(path.join(__dirname, "data", "witness.bin"));
const provingKey = fs.readFileSync(path.join(__dirname, "data", "proving_key.bin"));
const proofS = await bn128.proof(signals.buffer, provingKey.buffer);
const proofS = await bn128.groth16GenProof(signals.buffer, provingKey.buffer, true);

const proof = snarkjs.unstringifyBigInts(proofS);
const verifierKey = snarkjs.unstringifyBigInts(JSON.parse(fs.readFileSync(path.join(__dirname, "data", "verification_key.json"), "utf8")));
Expand Down