README.md

Hardhat Noir

Develop Noir with Hardhat without hassle.

What

Write programs in Noir, generate Solidity verifiers and run tests.

This plugin automatically manages nargo and bb versions and compiles Noir on demand.

Installation

Install the plugin and Noir dependencies:

npm install hardhat-plugin-noir @noir-lang/noir_js @noir-lang/backend_barretenberg

Import the plugin in your hardhat.config.js:

require("hardhat-plugin-noir");

Or if you are using TypeScript, in your hardhat.config.ts:

import "hardhat-plugin-noir";

Specify the Noir version in your Hardhat config:

You must enable Solidity optimizer in order to be able to deploy Solidity verifier contracts.

const config: HardhatUserConfig = {
  solidity: {
    version: "0.8.27",
    settings: {
      optimizer: {
        enabled: true,
        runs: 100000000,
      },
    },
  },
  noir: {
    version: "0.36.0",
  }
};

Usage

To get started, create a Noir circuit in noir folder:

npx hardhat noir-new my_noir

It will create noir/my_noir folder with the following src/main.nr:

fn main(x: Field, y: pub Field) {
    assert(x != y);
}

This circuit will prove that the private input x is not equal to the public input y using a zero-knowledge proof.

Compile Noir(it will also generate a Solidity verifier):

npx hardhat compile

Use the verifier contract in Solidity:

// contracts/MyContract.sol
import {UltraVerifier} from "../noir/target/my_noir.sol";

contract MyContract {
    UltraVerifier public verifier = new UltraVerifier();

    function verify(bytes calldata proof, uint256 y) external view returns (bool) {
        bytes32[] memory publicInputs = new bytes32[](1);
        publicInputs[0] = bytes32(y);
        bool result = verifier.verify(proof, publicInputs);
        return result;
    }
}

Generate a proof in TypeScript and verify it on chain:

// test/MyContract.test.ts
import { expect } from "chai";
import hre, { ethers } from "hardhat";

it("proves and verifies on-chain", async () => {
  // Deploy a verifier contract
  const contractFactory = await ethers.getContractFactory("MyContract");
  const contract = await contractFactory.deploy();
  await contract.waitForDeployment();

  // Generate a proof
  const { noir, backend } = await hre.noir.getCircuit("my_noir");
  const input = { x: 1, y: 2 };
  const { witness } = await noir.execute(input);
  const { proof, publicInputs } = await backend.generateProof(witness);
  // it matches because we marked y as `pub` in `main.nr`
  expect(BigInt(publicInputs[0])).to.eq(BigInt(input.y));

  // Verify the proof on-chain
  const result = await contract.verify(proof, input.y);
  expect(result).to.eq(true);

  // You can also verify in JavaScript.
  const resultJs = await backend.verifyProof({
    proof,
    publicInputs: [String(input.y)],
  });
  expect(resultJs).to.eq(true);
});

Tasks

This plugin creates no additional tasks. Run hardhat compile to compile Noir.

Environment extensions

This plugin extends the Hardhat Runtime Environment by adding a noir field.

You can call hre.noir.getCircuit(name) to get a compiled circuit JSON.

Configuration

Configure Noir and Barretenberg (bb) versions in hardhat.config.ts:

export default {
  noir: {
    // Noir version, optional, will use the latest known Noir version by default
    version: "0.36.0",
    // bb version, optional, will be inferred if possible
    bbVersion: "0.58.0",
  },
};

The default folder where Noir is located is noir. You can change it in hardhat.config.js:

export default {
  paths: {
    noir: "circuits",
  },
};