108 lines
3.8 KiB
JavaScript
108 lines
3.8 KiB
JavaScript
/*
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Copyright 2019 0KIMS association.
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This file is part of websnark (Web Assembly zkSnark Prover).
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websnark is a free software: you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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websnark is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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License for more details.
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You should have received a copy of the GNU General Public License
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along with websnark. If not, see <https://www.gnu.org/licenses/>.
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*/
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const bigInt = require("big-integer");
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const Circuit = require("snarkjs/src/circuit");
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const bigInt2 = require("snarkjs/src/bigint");
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const hexifyBigInts = require("../tools/stringifybigint").hexifyBigInts;
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const unhexifyBigInts = require("../tools/stringifybigint").unhexifyBigInts;
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const stringifyBigInts = require("../tools/stringifybigint").stringifyBigInts;
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const unstringifyBigInts = require("../tools/stringifybigint").unstringifyBigInts;
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const stringifyBigInts2 = require("snarkjs/src/stringifybigint").stringifyBigInts;
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const unstringifyBigInts2 = require("snarkjs/src/stringifybigint").unstringifyBigInts;
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function bigInt2BytesLE(_a, len) {
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const b = Array(len);
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let v = bigInt(_a);
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for (let i=0; i<len; i++) {
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b[i] = v.and(0xFF).toJSNumber();
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v = v.shiftRight(8);
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}
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return b;
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}
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function bigInt2U32LE(_a, len) {
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const b = Array(len);
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let v = bigInt(_a);
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for (let i=0; i<len; i++) {
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b[i] = v.and(0xFFFFFFFF).toJSNumber();
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v = v.shiftRight(32);
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}
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return b;
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}
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function convertWitness(witness) {
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const buffLen = witness.length * 32;
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const buff = new ArrayBuffer(buffLen);
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const h = {
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dataView: new DataView(buff),
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offset: 0
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};
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const mask = bigInt2(0xFFFFFFFF);
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for (let i = 0; i < witness.length; i++) {
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for (let j = 0; j < 8; j++) {
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const v = Number(witness[i].shr(j * 32).and(mask));
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h.dataView.setUint32(h.offset, v, true);
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h.offset += 4;
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}
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}
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return buff;
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}
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function toSolidityInput(proof) {
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const result = {
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pi_a: [proof.pi_a[0], proof.pi_a[1]],
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pi_b: [[proof.pi_b[0][1], proof.pi_b[0][0]], [proof.pi_b[1][1], proof.pi_b[1][0]]],
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pi_c: [proof.pi_c[0], proof.pi_c[1]],
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};
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if (proof.publicSignals) {
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result.publicSignals = proof.publicSignals;
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}
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return hexifyBigInts(unstringifyBigInts(result));
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}
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function fromSolidityInput(proof) {
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proof = unhexifyBigInts(proof);
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const result = {
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pi_a: [proof.pi_a[0], proof.pi_a[1], bigInt(1)],
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pi_b: [[proof.pi_b[0][1], proof.pi_b[0][0]], [proof.pi_b[1][1], proof.pi_b[1][0]], [bigInt(1), bigInt(0)]],
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pi_c: [proof.pi_c[0], proof.pi_c[1], bigInt(1)]
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};
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if (proof.publicSignals) {
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result.publicSignals = proof.publicSignals;
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}
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return stringifyBigInts(proof);
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}
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function genWitness(input, circuitJson) {
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const circuit = new Circuit(unstringifyBigInts2(circuitJson));
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const witness = circuit.calculateWitness(unstringifyBigInts2(input));
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const publicSignals = witness.slice(1, circuit.nPubInputs + circuit.nOutputs + 1);
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return {witness, publicSignals};
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}
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async function genWitnessAndProve(groth16, input, circuitJson, provingKey) {
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const witnessData = genWitness(input, circuitJson);
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const witnessBin = convertWitness(witnessData.witness);
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const result = await groth16.proof(witnessBin, provingKey);
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result.publicSignals = stringifyBigInts2(witnessData.publicSignals);
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return result;
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}
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module.exports = {bigInt2BytesLE, bigInt2U32LE, toSolidityInput, fromSolidityInput, genWitnessAndProve}; |