circomlib/test/eddsa.js

const chai = require("chai");
const path = require("path");
const snarkjs = require("@tornado/snarkjs");
const compiler = require("circom");
// const crypto = require("crypto");

const eddsa = require("../src/eddsa.js");
const babyJub = require("../src/babyjub.js");

const assert = chai.assert;

const bigInt = snarkjs.bigInt;

function print(circuit, w, s) {
    console.log(s + ": " + w[circuit.getSignalIdx(s)]);
}

function buffer2bits(buff) {
    const res = [];
    for (let i = 0; i < buff.length; i++) {
        for (let j = 0; j < 8; j++) {
            if ((buff[i] >> j) & 1) {
                res.push(bigInt.one);
            } else {
                res.push(bigInt.zero);
            }
        }
    }
    return res;
}

describe("EdDSA test", function () {
    let circuit;

    this.timeout(100000);

    before(async () => {
        const cirDef = await compiler(path.join(__dirname, "circuits", "eddsa_test.circom"));

        circuit = new snarkjs.Circuit(cirDef);

        console.log("NConstrains EdDSA: " + circuit.nConstraints);
    });

    it("Sign a single 10 bytes from 0 to 9", async () => {
        const msg = Buffer.from("00010203040506070809", "hex");

        //        const prvKey = crypto.randomBytes(32);

        const prvKey = Buffer.from("0001020304050607080900010203040506070809000102030405060708090001", "hex");

        const pubKey = eddsa.prv2pub(prvKey);

        const pPubKey = babyJub.packPoint(pubKey);

        const signature = eddsa.sign(prvKey, msg);

        const pSignature = eddsa.packSignature(signature);
        const uSignature = eddsa.unpackSignature(pSignature);

        assert(eddsa.verify(msg, uSignature, pubKey));

        const msgBits = buffer2bits(msg);
        const r8Bits = buffer2bits(pSignature.slice(0, 32));
        const sBits = buffer2bits(pSignature.slice(32, 64));
        const aBits = buffer2bits(pPubKey);

        const w = circuit.calculateWitness({ A: aBits, R8: r8Bits, S: sBits, msg: msgBits });

        assert(circuit.checkWitness(w));
    });
});