snarkjs/src/groth16_exportsoliditycalldata.js

zkSNARKs implementation in JavaScript

/*
    Copyright 2018 0KIMS association.

    This file is part of snarkJS.

    snarkJS is a free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    snarkJS is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
    License for more details.

    You should have received a copy of the GNU General Public License
    along with snarkJS. If not, see <https://www.gnu.org/licenses/>.
*/
import {  utils }   from "ffjavascript";
const { unstringifyBigInts} = utils;

function p256(n) {
    let nstr = n.toString(16);
    while (nstr.length < 64) nstr = "0"+nstr;
    nstr = `"0x${nstr}"`;
    return nstr;
}

export default async function groth16ExportSolidityCallData(_proof, _pub) {
    const proof = unstringifyBigInts(_proof);
    const pub = unstringifyBigInts(_pub);

    let inputs = "";
    for (let i=0; i<pub.length; i++) {
        if (inputs != "") inputs = inputs + ",";
        inputs = inputs + p256(pub[i]);
    }

    let S;
    S=`[${p256(proof.pi_a[0])}, ${p256(proof.pi_a[1])}],` +
        `[[${p256(proof.pi_b[0][1])}, ${p256(proof.pi_b[0][0])}],[${p256(proof.pi_b[1][1])}, ${p256(proof.pi_b[1][0])}]],` +
        `[${p256(proof.pi_c[0])}, ${p256(proof.pi_c[1])}],` +
        `[${inputs}]`;

    return S;
}