@unirep/contracts

Client library for contracts related functions which are used in UniRep protocol.

🛠 Install

npm or yarn

Install the @unirep/contracts package with npm:

npm i @unirep/contracts

or yarn:

yarn add @unirep/contracts

👩🏻‍⚕️ Haven't deployed a contract yet?

Get circuit keys from one of the following methods

🍀 Solution 1. Download circuit keys from server

(TODO) Get circuits files from PSE server

🍀 Solution 2. Build circuits locally

git clone https://github.com/Unirep/Unirep.git && \
cd Unirep/ && \
yarn install && \
yarn build

By default, The zksnarkBuild directory will be found in ./packages/circuits

Compile contracts from the keys

Step 1. Set the zksnarkBuild path in buildVerifier.ts

Step 2. Run compile command

By default, The artifacts directory will be found in ./packages/contracts/build

🙆🏻‍♀️ Unirep contract has been compiled

Deploy Unirep contract

Deploy Unirep smart contract with default config:

import ethers from 'ethers'
import { deployUnirep, Unirep } from '@unirep/contracts'

const privateKey = 'YOUR/PRIVATE/KEY'
const provider = 'YOUR/ETH/PROVIDER'
const deployer = new ethers.Wallet(privateKey, provider);

const unirepContract: Unirep = await deployUnirep(deployer)

(TODO) A deploy script

Get unirep contract with address

import ethers from 'ethers'
import { getUnirepContract, Unirep } from '@unirep/contracts'

const address = '0x....'
const provider = 'YOUR/ETH/PROVIDER'

const unirepContract: Unirep = getUnirepContract(address, provider)

🧑🏻‍💻 Call Unirep contract with ethers

import { ethers } from 'ethers'
import { ZkIdentity } from '@unirep/crypto'
import { getUnirepContract, Unirep } from '@unirep/contracts'

const address = '0x....'
const privateKey = 'YOUR/PRIVATE/KEY'
const provider = 'YOUR/ETH/PROVIDER'

// connect a signer
const signer = new ethers.Wallet(privateKey, provider)
const unirepContract: Unirep = getUnirepContract(address, signer)

// user sign up
const id = new ZkIdentity()
const tx = await unirepContract.userSignUp(id.genIdentityCommitment())

// attester sign up
const tx = await unirepContract.attesterSignUp()

🙋🏻‍♂️ Call Unirep contract in DApps

• 🚸 Please copy verifiers/*.sol files to node_modules/@unirep/contracts/verifiers/ directories.

  cp -rf ../Unirep/packages/contracts/contracts/verifiers/* ./node_modules/@unirep/contracts/verifiers

  (TODO) Find a better way to do this.

import { Unirep } from '@unirep/contracts/Unirep.sol';

contract YourContract {
    Unirep public unirep;

    uint256 internal _attesterId;

    // Initialize contract with a deployed
    constructor(Unirep _unirepContract) {
        // Set the unirep contract address
        unirep = _unirepContract;
    }

    // Relay Users sign up in Unirep
    function signUp(uint256 idCommitment) external {
        unirep.userSignUp(idCommitment);
    }

    // Sign up this contract as an attester
    function signUpContract() external {
        unirep.attesterSignUp();
        _attesterId = unirep.attesters(address(this));
    }

    // Users submit their epoch key proof to Unirep contract
    // And get attestation from the contract
    function submitEpochKeyProof(Unirep.EpochKeyProof memory input)
        external
        payable
    {
        // Step 1. submit epoch key proof
        unirep.submitEpochKeyProof(input);

        // Step 2. get proof index
        bytes32 proofNullifier = unirep.hashEpochKeyProof(input);
        uint256 proofIndex = unirep.getProofIndex(proofNullifier);

        // Step 3. init attestation
        // create an attestation which sends 5 positive Rep to the epochKey
        Unirep.Attestation memory attestation;
        attestation.attesterId = _attesterId;
        attestation.posRep = 5;

        // Step 4. send attestation
        unirep.submitAttestation{ value: unirep.attestingFee() }(
            attestation,
            input.epochKey,
            proofIndex,
            0 // if no reputation spent required
        );
    }
}

📚 Other usages

Proofs

An example of epoch key proof 1. Generate an epoch key proof structure

import { Circuit } from '@unirep/circuits'
import { EpochKeyProof } from '@unirep/contracts'

// see @unirep/circuits to know how to generate a prover and circuitInputs
const prover = {
    ...
}
const circuitInputs = {
    ...
}

const { publicSignals, proof } = await prover.genProofAndPublicSignals(
    Circuit.verifyEpochKey,
    circuitInputs
)

const epkProof = new EpochKeyProof(
    publicSignals,
    proof,
    prover
)

2. Get data from epoch key proof structure

const epoch = epkProof.epoch
const epochKey = epkProof.epochKey
const globalStateTree = epkProof.globalStateTree

3. Verify the epoch key proof

const isValid = await epkProof.verify()

4. Compute keccak256 hash of the proof

const hash = epkProof.hash()

5. The proof structure can help with formatting the proof on chain

const tx = await unirepContract.submitEpochKeyProof(
    epkProof.publicSignals,
    epkProof.proof
)

Attestation

An example of constructing an Attestation object

import { Attestation } from '@unirep/contracts'

const attestation = new Attestation(
    attesterID,
    positiveReputation,
    negativeReputation,
    graffiti,
    signUpFlag
)
const hash = attestation.hash()

Event/ Attestation event

The event enum is used to help with determining the type of the event, which are as the same definition in IUnirep.sol