tornado-nova/test/full.test.js

const hre = require('hardhat')
const { ethers, waffle } = hre
const { loadFixture } = waffle
const { expect } = require('chai')

const { poseidonHash2, toFixedHex } = require('../src/utils')
const Utxo = require('../src/utxo')

const MERKLE_TREE_HEIGHT = 5
const MerkleTree = require('fixed-merkle-tree')

const { transaction, registerAndTransact } = require('../src/index')
const { Keypair } = require('../src/keypair')

describe('TornadoPool', function () {
  this.timeout(20000)

  async function deploy(contractName, ...args) {
    const Factory = await ethers.getContractFactory(contractName)
    const instance = await Factory.deploy(...args)
    return instance.deployed()
  }

  async function fixture() {
    const verifier2 = await deploy('Verifier2')
    const verifier16 = await deploy('Verifier16')

    const tree = new MerkleTree(MERKLE_TREE_HEIGHT, [], { hashFunction: poseidonHash2 })
    /** @type {TornadoPool} */
    const tornadoPool = await deploy(
      'TornadoPool',
      verifier2.address,
      verifier16.address,
      toFixedHex(tree.root()),
    )

    return { tornadoPool }
  }

  it('encrypt -> decrypt should work', () => {
    const data = Buffer.from([0xff, 0xaa, 0x00, 0x01])
    const keypair = new Keypair()

    const ciphertext = keypair.encrypt(data)
    const result = keypair.decrypt(ciphertext)
    expect(result).to.be.deep.equal(data)
  })

  it('constants check', async () => {
    const { tornadoPool } = await loadFixture(fixture)
    const maxFee = await tornadoPool.MAX_FEE()
    const maxExtAmount = await tornadoPool.MAX_EXT_AMOUNT()
    const fieldSize = await tornadoPool.FIELD_SIZE()

    expect(maxExtAmount.add(maxFee)).to.be.lt(fieldSize)
  })

  it('should register and deposit', async function () {
    let { tornadoPool } = await loadFixture(fixture)
    const sender = (await ethers.getSigners())[1]

    // Alice deposits into tornado pool
    const aliceDepositAmount = 1e7
    const aliceDepositUtxo = new Utxo({ amount: aliceDepositAmount })

    const backupAccount = new Keypair()

    const bufferPrivateKey = Buffer.from(aliceDepositUtxo.keypair.privkey)
    const packedPrivateKeyData = backupAccount.encrypt(bufferPrivateKey)

    tornadoPool = tornadoPool.connect(sender)
    await registerAndTransact({
      tornadoPool,
      packedPrivateKeyData,
      outputs: [aliceDepositUtxo],
      poolAddress: aliceDepositUtxo.keypair.address(),
    })

    const filter = tornadoPool.filters.NewCommitment()
    const fromBlock = await ethers.provider.getBlock()
    const events = await tornadoPool.queryFilter(filter, fromBlock.number)

    let aliceReceiveUtxo
    try {
      aliceReceiveUtxo = Utxo.decrypt(
        aliceDepositUtxo.keypair,
        events[0].args.encryptedOutput,
        events[0].args.index,
      )
    } catch (e) {
      // we try to decrypt another output here because it shuffles outputs before sending to blockchain
      aliceReceiveUtxo = Utxo.decrypt(
        aliceDepositUtxo.keypair,
        events[1].args.encryptedOutput,
        events[1].args.index,
      )
    }
    expect(aliceReceiveUtxo.amount).to.be.equal(aliceDepositAmount)

    const filterRegister = tornadoPool.filters.PublicKey(sender.address)
    const filterFromBlock = await ethers.provider.getBlock()
    const registerEvents = await tornadoPool.queryFilter(filterRegister, filterFromBlock.number)

    const [registerEvent] = registerEvents.sort((a, b) => a.blockNumber - b.blockNumber).slice(-1)

    expect(registerEvent.args.key).to.be.equal(aliceDepositUtxo.keypair.address())

    const accountFilter = tornadoPool.filters.EncryptedAccount(sender.address)
    const accountFromBlock = await ethers.provider.getBlock()
    const accountEvents = await tornadoPool.queryFilter(accountFilter, accountFromBlock.number)

    const [accountEvent] = accountEvents.sort((a, b) => a.blockNumber - b.blockNumber).slice(-1)

    const privateKey = backupAccount.decrypt(accountEvent.args.account)

    expect(bufferPrivateKey.toString('hex')).to.be.equal(privateKey.toString('hex'))
  })

  it('should deposit, transact and withdraw', async function () {
    const { tornadoPool } = await loadFixture(fixture)

    // Alice deposits into tornado pool
    const aliceDepositAmount = 1e7
    const aliceDepositUtxo = new Utxo({ amount: aliceDepositAmount })
    await transaction({ tornadoPool, outputs: [aliceDepositUtxo] })

    // Bob gives Alice address to send some eth inside the shielded pool
    const bobKeypair = new Keypair() // contains private and public keys
    const bobAddress = bobKeypair.address() // contains only public key

    // Alice sends some funds to Bob
    const bobSendAmount = 3e6
    const bobSendUtxo = new Utxo({ amount: bobSendAmount, keypair: Keypair.fromString(bobAddress) })
    const aliceChangeUtxo = new Utxo({
      amount: aliceDepositAmount - bobSendAmount,
      keypair: aliceDepositUtxo.keypair,
    })
    await transaction({ tornadoPool, inputs: [aliceDepositUtxo], outputs: [bobSendUtxo, aliceChangeUtxo] })

    // Bob parses chain to detect incoming funds
    const filter = tornadoPool.filters.NewCommitment()
    const fromBlock = await ethers.provider.getBlock()
    const events = await tornadoPool.queryFilter(filter, fromBlock.number)
    let bobReceiveUtxo
    try {
      bobReceiveUtxo = Utxo.decrypt(bobKeypair, events[0].args.encryptedOutput, events[0].args.index)
    } catch (e) {
      // we try to decrypt another output here because it shuffles outputs before sending to blockchain
      bobReceiveUtxo = Utxo.decrypt(bobKeypair, events[1].args.encryptedOutput, events[1].args.index)
    }
    expect(bobReceiveUtxo.amount).to.be.equal(bobSendAmount)

    // Bob withdraws a part of his funds from the shielded pool
    const bobWithdrawAmount = 2e6
    const bobEthAddress = '0xDeaD00000000000000000000000000000000BEEf'
    const bobChangeUtxo = new Utxo({ amount: bobSendAmount - bobWithdrawAmount, keypair: bobKeypair })
    await transaction({
      tornadoPool,
      inputs: [bobReceiveUtxo],
      outputs: [bobChangeUtxo],
      recipient: bobEthAddress,
    })

    const bobBalance = await ethers.provider.getBalance(bobEthAddress)
    expect(bobBalance).to.be.equal(bobWithdrawAmount)
  })

  it('should work with 16 inputs', async function () {
    const { tornadoPool } = await loadFixture(fixture)
    await transaction({ tornadoPool, inputs: [new Utxo(), new Utxo(), new Utxo()] })
  })
})