> For the complete documentation index, see [llms.txt](https://unirep.gitbook.io/unirep/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://unirep.gitbook.io/unirep/package/contracts.md).

# @unirep/contracts

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### 🛠 Install

#### npm or yarn

Install the `@unirep/contracts` package with npm:

```bash
npm i @unirep/contracts
```

or yarn:

```bash
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*](http://www.trusted-setup-pse.org/)

**🍀 Solution 2. Build circuits locally**

```bash
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:

```typescript
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

```typescript
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`

```typescript
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.*

```solidity
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**

```typescript
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**

```typescript
const epoch = epkProof.epoch
const epochKey = epkProof.epochKey
const globalStateTree = epkProof.globalStateTree
```

**3. Verify the epoch key proof**

```typescript
const isValid = await epkProof.verify()
```

**4. Compute keccak256 hash of the proof**

```typescript
const hash = epkProof.hash()
```

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

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

#### Attestation

**An example of constructing an Attestation object**

```typescript
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`