circomlib/test/sha256.js

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

const compiler = require("circom");

const assert = chai.assert;

const sha256 = require("./helpers/sha256");

// const printSignal = require("./helpers/printsignal");

function buffer2bitArray(b) {
    const res = [];
    for (let i = 0; i < b.length; i++) {
        for (let j = 0; j < 8; j++) {
            res.push((b[i] >> (7 - j)) & 1);
        }
    }
    return res;
}

function bitArray2buffer(a) {
    const len = Math.floor((a.length - 1) / 8) + 1;
    const b = new Buffer.alloc(len);

    for (let i = 0; i < a.length; i++) {
        const p = Math.floor(i / 8);
        b[p] = b[p] | (Number(a[i]) << (7 - (i % 8)));
    }
    return b;
}

describe("SHA256 test", () => {
    it("Should work bits to array and array to bits", async () => {
        const b = new Buffer.alloc(64);
        for (let i = 0; i < 64; i++) {
            b[i] = i + 1;
        }
        const a = buffer2bitArray(b);
        const b2 = bitArray2buffer(a);

        assert.equal(b.toString("hex"), b2.toString("hex"));
    });

    it("Should calculate a hash of 1 compressor", async () => {
        const cirDef = await compiler(path.join(__dirname, "circuits", "sha256_2_test.circom"));
        const circuit = new snarkjs.Circuit(cirDef);

        console.log("Vars: " + circuit.nVars);
        console.log("Constraints: " + circuit.nConstraints);

        const witness = circuit.calculateWitness({ a: "1", b: "2" });

        const b = new Buffer.alloc(54);
        b[26] = 1;
        b[53] = 2;

        const hash = crypto.createHash("sha256").update(b).digest("hex");
        const r = "0x" + hash.slice(10);

        const hash2 = sha256.hash(b.toString("hex"), { msgFormat: "hex-bytes" });

        assert.equal(hash, hash2);

        assert(witness[1].equals(snarkjs.bigInt(r)));
    }).timeout(1000000);

    it("Should calculate a hash of 2 compressor", async () => {
        const cirDef = await compiler(path.join(__dirname, "circuits", "sha256_test512.circom"), { reduceConstraints: false });
        const circuit = new snarkjs.Circuit(cirDef);

        console.log("Vars: " + circuit.nVars);
        console.log("Constraints: " + circuit.nConstraints);

        /*
        const testStr = "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq";

        const b = Buffer.from(testStr, 'utf8');
*/
        const b = new Buffer.alloc(64);
        for (let i = 0; i < 64; i++) {
            b[i] = i + 1;
        }

        const hash = crypto.createHash("sha256").update(b).digest("hex");

        const arrIn = buffer2bitArray(b);
        const witness = circuit.calculateWitness({ in: arrIn } /*, {logOutput: true} */);

        const arrOut = witness.slice(1, 257);
        const hash2 = bitArray2buffer(arrOut).toString("hex");

        assert.equal(hash, hash2);
    }).timeout(1000000);

    it("Should calculate a hash of 2 compressor", async () => {
        const cirDef = await compiler(path.join(__dirname, "circuits", "sha256_test448.circom"), { reduceConstraints: false });
        const circuit = new snarkjs.Circuit(cirDef);

        console.log("Vars: " + circuit.nVars);
        console.log("Constraints: " + circuit.nConstraints);

        const testStr = "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq";

        const b = Buffer.from(testStr, "utf8");
        for (let i = 0; i < 64; i++) {
            b[i] = i + 1;
        }

        const hash = crypto.createHash("sha256").update(b).digest("hex");

        const arrIn = buffer2bitArray(b);
        const witness = circuit.calculateWitness({ in: arrIn } /*, {logOutput: true} */);

        const arrOut = witness.slice(1, 257);
        const hash2 = bitArray2buffer(arrOut).toString("hex");

        assert.equal(hash, hash2);
    }).timeout(1000000);
});