tornado-core/test/Mixer.test.js
2019-07-25 16:58:21 +03:00

362 lines
13 KiB
JavaScript

/* global artifacts, web3, contract */
require('chai')
.use(require('bn-chai')(web3.utils.BN))
.use(require('chai-as-promised'))
.should()
const fs = require('fs')
const { toBN, toHex, randomHex } = require('web3-utils')
const { takeSnapshot, revertSnapshot } = require('../lib/ganacheHelper')
const Mixer = artifacts.require('./Mixer.sol')
const { AMOUNT, MERKLE_TREE_HEIGHT, EMPTY_ELEMENT } = process.env
const websnarkUtils = require('websnark/src/utils')
const buildGroth16 = require('websnark/src/groth16')
const stringifyBigInts = require('websnark/tools/stringifybigint').stringifyBigInts
const unstringifyBigInts2 = require('snarkjs/src/stringifybigint').unstringifyBigInts
const snarkjs = require('snarkjs')
const bigInt = snarkjs.bigInt
const crypto = require('crypto')
const circomlib = require('circomlib')
const MerkleTree = require('../lib/MerkleTree')
const rbigint = (nbytes) => snarkjs.bigInt.leBuff2int(crypto.randomBytes(nbytes))
const pedersenHash = (data) => circomlib.babyJub.unpackPoint(circomlib.pedersenHash.hash(data))[0]
function generateDeposit() {
let deposit = {
secret: rbigint(31),
nullifier: rbigint(31),
}
const preimage = Buffer.concat([deposit.nullifier.leInt2Buff(32), deposit.secret.leInt2Buff(32)])
deposit.commitment = pedersenHash(preimage)
return deposit
}
// eslint-disable-next-line no-unused-vars
function BNArrayToStringArray(array) {
const arrayToPrint = []
array.forEach(item => {
arrayToPrint.push(item.toString())
})
return arrayToPrint
}
function getRandomReceiver() {
let receiver = rbigint(20)
while (toHex(receiver.toString()).length !== 42) {
receiver = rbigint(20)
}
return receiver
}
function snarkVerify(proof) {
proof = unstringifyBigInts2(websnarkUtils.fromSolidityInput(proof))
const verification_key = unstringifyBigInts2(require('../build/circuits/withdraw_verification_key.json'))
return snarkjs['groth'].isValid(verification_key, proof, proof.publicSignals)
}
contract('Mixer', accounts => {
let mixer
const sender = accounts[0]
const levels = MERKLE_TREE_HEIGHT || 16
const zeroValue = EMPTY_ELEMENT || 1337
const value = AMOUNT || '1000000000000000000'
let snapshotId
let prefix = 'test'
let tree
const fee = bigInt(1e17)
const receiver = getRandomReceiver()
const relayer = accounts[1]
let groth16
let circuit
let proving_key
before(async () => {
tree = new MerkleTree(
levels,
zeroValue,
null,
prefix,
)
mixer = await Mixer.deployed()
snapshotId = await takeSnapshot()
groth16 = await buildGroth16()
circuit = require('../build/circuits/withdraw.json')
proving_key = fs.readFileSync('build/circuits/withdraw_proving_key.bin').buffer
})
describe('#constructor', () => {
it('should initialize', async () => {
const transferValue = await mixer.transferValue()
transferValue.should.be.eq.BN(toBN(value))
})
})
describe('#deposit', () => {
it('should emit event', async () => {
let commitment = 42
let { logs } = await mixer.deposit(commitment, { value, from: sender })
logs[0].event.should.be.equal('Deposit')
logs[0].args.commitment.should.be.eq.BN(toBN(commitment))
logs[0].args.leafIndex.should.be.eq.BN(toBN(0))
commitment = 12;
({ logs } = await mixer.deposit(commitment, { value, from: accounts[2] }))
logs[0].event.should.be.equal('Deposit')
logs[0].args.commitment.should.be.eq.BN(toBN(commitment))
logs[0].args.leafIndex.should.be.eq.BN(toBN(1))
})
it('should throw if there is a such commitment', async () => {
const commitment = 42
await mixer.deposit(commitment, { value, from: sender }).should.be.fulfilled
const error = await mixer.deposit(commitment, { value, from: sender }).should.be.rejected
error.reason.should.be.equal('The commitment has been submitted')
})
})
describe('snark proof verification on js side', () => {
it('should detect tampering', async () => {
const deposit = generateDeposit()
await tree.insert(deposit.commitment)
const { root, path_elements, path_index } = await tree.path(0)
const input = stringifyBigInts({
root,
nullifierHash: pedersenHash(deposit.nullifier.leInt2Buff(32)),
nullifier: deposit.nullifier,
receiver,
fee,
secret: deposit.secret,
pathElements: path_elements,
pathIndex: path_index,
})
let proof = await websnarkUtils.genWitnessAndProve(groth16, input, circuit, proving_key)
const originalProof = JSON.parse(JSON.stringify(proof))
let result = snarkVerify(proof)
result.should.be.equal(true)
// nullifier
proof.publicSignals[1] = '133792158246920651341275668520530514036799294649489851421007411546007850802'
result = snarkVerify(proof)
result.should.be.equal(false)
proof = originalProof
// try to cheat with recipient
proof.publicSignals[2] = '133738360804642228759657445999390850076318544422'
result = snarkVerify(proof)
result.should.be.equal(false)
proof = originalProof
// fee
proof.publicSignals[3] = '1337100000000000000000'
result = snarkVerify(proof)
result.should.be.equal(false)
proof = originalProof
})
})
describe('#withdraw', () => {
it('should work', async () => {
const deposit = generateDeposit()
const user = accounts[4]
await tree.insert(deposit.commitment)
const balanceUserBefore = await web3.eth.getBalance(user)
await mixer.deposit(toBN(deposit.commitment.toString()), { value, from: user, gasPrice: '0' })
const balanceUserAfter = await web3.eth.getBalance(user)
balanceUserAfter.should.be.eq.BN(toBN(balanceUserBefore).sub(toBN(value)))
const { root, path_elements, path_index } = await tree.path(0)
// Circuit input
const input = stringifyBigInts({
// public
root,
nullifierHash: pedersenHash(deposit.nullifier.leInt2Buff(32)),
receiver,
fee,
// private
nullifier: deposit.nullifier,
secret: deposit.secret,
pathElements: path_elements,
pathIndex: path_index,
})
const proof = await websnarkUtils.genWitnessAndProve(groth16, input, circuit, proving_key)
const { pi_a, pi_b, pi_c, publicSignals } = websnarkUtils.toSolidityInput(proof)
const balanceMixerBefore = await web3.eth.getBalance(mixer.address)
const balanceRelayerBefore = await web3.eth.getBalance(relayer)
const balanceRecieverBefore = await web3.eth.getBalance(toHex(receiver.toString()))
let isSpent = await mixer.isSpent(input.nullifierHash.toString(16).padStart(66, '0x00000'))
isSpent.should.be.equal(false)
const { logs } = await mixer.withdraw(pi_a, pi_b, pi_c, publicSignals, { from: relayer, gasPrice: '0' })
const balanceMixerAfter = await web3.eth.getBalance(mixer.address)
const balanceRelayerAfter = await web3.eth.getBalance(relayer)
const balanceRecieverAfter = await web3.eth.getBalance(toHex(receiver.toString()))
const feeBN = toBN(fee.toString())
balanceMixerAfter.should.be.eq.BN(toBN(balanceMixerBefore).sub(toBN(value)))
balanceRelayerAfter.should.be.eq.BN(toBN(balanceRelayerBefore).add(feeBN))
balanceRecieverAfter.should.be.eq.BN(toBN(balanceRecieverBefore).add(toBN(value)).sub(feeBN))
logs[0].event.should.be.equal('Withdraw')
logs[0].args.nullifierHash.should.be.eq.BN(toBN(input.nullifierHash.toString()))
logs[0].args.fee.should.be.eq.BN(feeBN)
isSpent = await mixer.isSpent(input.nullifierHash.toString(16).padStart(66, '0x00000'))
isSpent.should.be.equal(true)
})
it('should prevent double spend', async () => {
const deposit = generateDeposit()
await tree.insert(deposit.commitment)
await mixer.deposit(toBN(deposit.commitment.toString()), { value, from: sender })
const { root, path_elements, path_index } = await tree.path(0)
const input = stringifyBigInts({
root,
nullifierHash: pedersenHash(deposit.nullifier.leInt2Buff(32)),
nullifier: deposit.nullifier,
receiver,
fee,
secret: deposit.secret,
pathElements: path_elements,
pathIndex: path_index,
})
const proof = await websnarkUtils.genWitnessAndProve(groth16, input, circuit, proving_key)
const { pi_a, pi_b, pi_c, publicSignals } = websnarkUtils.toSolidityInput(proof)
await mixer.withdraw(pi_a, pi_b, pi_c, publicSignals, { from: relayer }).should.be.fulfilled
const error = await mixer.withdraw(pi_a, pi_b, pi_c, publicSignals, { from: relayer }).should.be.rejected
error.reason.should.be.equal('The note has been already spent')
})
it('fee should be less or equal transfer value', async () => {
const deposit = generateDeposit()
await tree.insert(deposit.commitment)
await mixer.deposit(toBN(deposit.commitment.toString()), { value, from: sender })
const { root, path_elements, path_index } = await tree.path(0)
const oneEtherFee = bigInt(1e18) // 1 ether
const input = stringifyBigInts({
root,
nullifierHash: pedersenHash(deposit.nullifier.leInt2Buff(32)),
nullifier: deposit.nullifier,
receiver,
fee: oneEtherFee,
secret: deposit.secret,
pathElements: path_elements,
pathIndex: path_index,
})
const proof = await websnarkUtils.genWitnessAndProve(groth16, input, circuit, proving_key)
const { pi_a, pi_b, pi_c, publicSignals } = websnarkUtils.toSolidityInput(proof)
const error = await mixer.withdraw(pi_a, pi_b, pi_c, publicSignals, { from: relayer }).should.be.rejected
error.reason.should.be.equal('Fee exceeds transfer value')
})
it('should throw for corrupted merkle tree root', async () => {
const deposit = generateDeposit()
await tree.insert(deposit.commitment)
await mixer.deposit(toBN(deposit.commitment.toString()), { value, from: sender })
const { root, path_elements, path_index } = await tree.path(0)
const input = stringifyBigInts({
nullifierHash: pedersenHash(deposit.nullifier.leInt2Buff(32)),
root,
nullifier: deposit.nullifier,
receiver,
fee,
secret: deposit.secret,
pathElements: path_elements,
pathIndex: path_index,
})
const dummyRoot = randomHex(32)
const proof = await websnarkUtils.genWitnessAndProve(groth16, input, circuit, proving_key)
const { pi_a, pi_b, pi_c, publicSignals } = websnarkUtils.toSolidityInput(proof)
publicSignals[0] = dummyRoot
const error = await mixer.withdraw(pi_a, pi_b, pi_c, publicSignals, { from: relayer }).should.be.rejected
error.reason.should.be.equal('Cannot find your merkle root')
})
it('should reject with tampered public inputs', async () => {
const deposit = generateDeposit()
await tree.insert(deposit.commitment)
await mixer.deposit(toBN(deposit.commitment.toString()), { value, from: sender })
let { root, path_elements, path_index } = await tree.path(0)
const input = stringifyBigInts({
root,
nullifierHash: pedersenHash(deposit.nullifier.leInt2Buff(32)),
nullifier: deposit.nullifier,
receiver,
fee,
secret: deposit.secret,
pathElements: path_elements,
pathIndex: path_index,
})
const proof = await websnarkUtils.genWitnessAndProve(groth16, input, circuit, proving_key)
let { pi_a, pi_b, pi_c, publicSignals } = websnarkUtils.toSolidityInput(proof)
const originalPublicSignals = publicSignals.slice()
const originalPi_a = pi_a.slice()
// receiver
publicSignals[2] = '0x0000000000000000000000007a1f9131357404ef86d7c38dbffed2da70321337'
let error = await mixer.withdraw(pi_a, pi_b, pi_c, publicSignals, { from: relayer }).should.be.rejected
error.reason.should.be.equal('Invalid withdraw proof')
// fee
publicSignals = originalPublicSignals.slice()
publicSignals[3] = '0x000000000000000000000000000000000000000000000000015345785d8a0000'
error = await mixer.withdraw(pi_a, pi_b, pi_c, publicSignals, { from: relayer }).should.be.rejected
error.reason.should.be.equal('Invalid withdraw proof')
// nullifier
publicSignals = originalPublicSignals.slice()
publicSignals[1] = '0x00abdfc78211f8807b9c6504a6e537e71b8788b2f529a95f1399ce124a8642ad'
error = await mixer.withdraw(pi_a, pi_b, pi_c, publicSignals, { from: relayer }).should.be.rejected
error.reason.should.be.equal('Invalid withdraw proof')
// proof itself
pi_a[0] = '0x261d81d8203437f29b38a88c4263476d858e6d9645cf21740461684412b31337'
await mixer.withdraw(pi_a, pi_b, pi_c, originalPublicSignals, { from: relayer }).should.be.rejected
// should work with original values
await mixer.withdraw(originalPi_a, pi_b, pi_c, originalPublicSignals, { from: relayer }).should.be.fulfilled
})
})
afterEach(async () => {
await revertSnapshot(snapshotId.result)
// eslint-disable-next-line require-atomic-updates
snapshotId = await takeSnapshot()
tree = new MerkleTree(
levels,
zeroValue,
null,
prefix,
)
})
})