345 lines
13 KiB
JavaScript
Executable File
345 lines
13 KiB
JavaScript
Executable File
#!/usr/bin/env node
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// Temporary demo client
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// Works both in browser and node.js
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const fs = require('fs')
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const assert = require('assert')
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const snarkjs = require('snarkjs')
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const crypto = require('crypto')
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const circomlib = require('circomlib')
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const bigInt = snarkjs.bigInt
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const merkleTree = require('./lib/MerkleTree')
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const Web3 = require('web3')
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const buildGroth16 = require('websnark/src/groth16')
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const websnarkUtils = require('websnark/src/utils')
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let web3, mixer, erc20mixer, circuit, proving_key, groth16, erc20
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let MERKLE_TREE_HEIGHT, ETH_AMOUNT, EMPTY_ELEMENT, ERC20_TOKEN
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const inBrowser = (typeof window !== 'undefined')
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/** Generate random number of specified byte length */
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const rbigint = (nbytes) => snarkjs.bigInt.leBuff2int(crypto.randomBytes(nbytes))
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/** Compute pedersen hash */
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const pedersenHash = (data) => circomlib.babyJub.unpackPoint(circomlib.pedersenHash.hash(data))[0]
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/**
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* Create deposit object from secret and nullifier
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*/
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function createDeposit(nullifier, secret) {
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let deposit = { nullifier, secret }
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deposit.preimage = Buffer.concat([deposit.nullifier.leInt2Buff(31), deposit.secret.leInt2Buff(31)])
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deposit.commitment = pedersenHash(deposit.preimage)
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return deposit
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}
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/**
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* Make a deposit
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* @returns {Promise<string>}
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*/
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async function deposit() {
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const deposit = createDeposit(rbigint(31), rbigint(31))
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console.log('Submitting deposit transaction')
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await mixer.methods.deposit('0x' + deposit.commitment.toString(16)).send({ value: ETH_AMOUNT, from: (await web3.eth.getAccounts())[0], gas:4e6 })
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const note = '0x' + deposit.preimage.toString('hex')
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console.log('Your note:', note)
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return note
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}
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async function depositErc20() {
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const account = (await web3.eth.getAccounts())[0]
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const tokenAmount = process.env.TOKEN_AMOUNT
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await erc20.methods.mint(account, tokenAmount).send({ from: account, gas:1e6 })
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await erc20.methods.approve(erc20mixer.address, tokenAmount).send({ from: account, gas:1e6 })
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const allowance = await erc20.methods.allowance(account, erc20mixer.address).call()
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console.log('erc20mixer allowance', allowance.toString(10))
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const deposit = createDeposit(rbigint(31), rbigint(31))
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await erc20mixer.methods.deposit('0x' + deposit.commitment.toString(16)).send({ value: ETH_AMOUNT, from: account, gas:4e6 })
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const balance = await erc20.methods.balanceOf(erc20mixer.address).call()
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console.log('erc20mixer balance', balance.toString(10))
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const note = '0x' + deposit.preimage.toString('hex')
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console.log('Your note:', note)
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return note
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}
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async function withdrawErc20(note, receiver, relayer) {
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let buf = Buffer.from(note.slice(2), 'hex')
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let deposit = createDeposit(bigInt.leBuff2int(buf.slice(0, 31)), bigInt.leBuff2int(buf.slice(31, 62)))
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console.log('Getting current state from mixer contract')
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const events = await erc20mixer.getPastEvents('Deposit', { fromBlock: erc20mixer.deployedBlock, toBlock: 'latest' })
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let leafIndex
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const commitment = deposit.commitment.toString(16).padStart('66', '0x000000')
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const leaves = events
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.sort((a, b) => a.returnValues.leafIndex.sub(b.returnValues.leafIndex))
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.map(e => {
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if (e.returnValues.commitment.eq(commitment)) {
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leafIndex = e.returnValues.leafIndex.toNumber()
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}
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return e.returnValues.commitment
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})
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const tree = new merkleTree(MERKLE_TREE_HEIGHT, EMPTY_ELEMENT, leaves)
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const validRoot = await erc20mixer.methods.isKnownRoot(await tree.root()).call()
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const nullifierHash = pedersenHash(deposit.nullifier.leInt2Buff(31))
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const nullifierHashToCheck = nullifierHash.toString(16).padStart('66', '0x000000')
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const isSpent = await erc20mixer.methods.isSpent(nullifierHashToCheck).call()
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assert(validRoot === true)
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assert(isSpent === false)
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assert(leafIndex >= 0)
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const { root, path_elements, path_index } = await tree.path(leafIndex)
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// Circuit input
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const input = {
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// public
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root: root,
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nullifierHash,
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receiver: bigInt(receiver),
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relayer: bigInt(relayer),
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fee: bigInt(web3.utils.toWei('0.01')),
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// private
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nullifier: deposit.nullifier,
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secret: deposit.secret,
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pathElements: path_elements,
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pathIndex: path_index,
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}
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console.log('Generating SNARK proof')
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console.time('Proof time')
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const proofData = await websnarkUtils.genWitnessAndProve(groth16, input, circuit, proving_key)
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const { proof, publicSignals } = websnarkUtils.toSolidityInput(proofData)
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console.timeEnd('Proof time')
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console.log('Submitting withdraw transaction')
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await erc20mixer.methods.withdraw(proof, publicSignals).send({ from: (await web3.eth.getAccounts())[0], gas: 4e6 })
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console.log('Done')
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}
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async function getBalance(receiver) {
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const balance = await web3.eth.getBalance(receiver)
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console.log('Balance is ', web3.utils.fromWei(balance))
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}
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async function getBalanceErc20(receiver, relayer) {
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const balanceReceiver = await web3.eth.getBalance(receiver)
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const balanceRelayer = await web3.eth.getBalance(relayer)
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const tokenBalanceReceiver = await erc20.methods.balanceOf(receiver).call()
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const tokenBalanceRelayer = await erc20.methods.balanceOf(relayer).call()
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console.log('Receiver eth Balance is ', web3.utils.fromWei(balanceReceiver))
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console.log('Relayer eth Balance is ', web3.utils.fromWei(balanceRelayer))
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console.log('Receiver token Balance is ', web3.utils.fromWei(tokenBalanceReceiver.toString()))
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console.log('Relayer token Balance is ', web3.utils.fromWei(tokenBalanceRelayer.toString()))
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}
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async function withdraw(note, receiver) {
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// Decode hex string and restore the deposit object
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let buf = Buffer.from(note.slice(2), 'hex')
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let deposit = createDeposit(bigInt.leBuff2int(buf.slice(0, 31)), bigInt.leBuff2int(buf.slice(31, 62)))
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const nullifierHash = pedersenHash(deposit.nullifier.leInt2Buff(31))
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const paddedNullifierHash = nullifierHash.toString(16).padStart('66', '0x000000')
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const paddedCommitment = deposit.commitment.toString(16).padStart('66', '0x000000')
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// Get all deposit events from smart contract and assemble merkle tree from them
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console.log('Getting current state from mixer contract')
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const events = await mixer.getPastEvents('Deposit', { fromBlock: mixer.deployedBlock, toBlock: 'latest' })
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const leaves = events
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.sort((a, b) => a.returnValues.leafIndex.sub(b.returnValues.leafIndex)) // Sort events in chronological order
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.map(e => e.returnValues.commitment)
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const tree = new merkleTree(MERKLE_TREE_HEIGHT, EMPTY_ELEMENT, leaves)
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// Find current commitment in the tree
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let depositEvent = events.find(e => e.returnValues.commitment.eq(paddedCommitment))
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let leafIndex = depositEvent ? depositEvent.returnValues.leafIndex.toNumber() : -1
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// Validate that our data is correct
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const isValidRoot = await mixer.methods.isKnownRoot(await tree.root()).call()
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const isSpent = await mixer.methods.isSpent(paddedNullifierHash).call()
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assert(isValidRoot === true) // Merkle tree assembled correctly
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assert(isSpent === false) // The note is not spent
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assert(leafIndex >= 0) // Our deposit is present in the tree
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// Compute merkle proof of our commitment
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const { root, path_elements, path_index } = await tree.path(leafIndex)
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// Prepare circuit input
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const input = {
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// Public snark inputs
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root: root,
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nullifierHash,
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receiver: bigInt(receiver),
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relayer: bigInt(0),
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fee: bigInt(0),
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// Private snark inputs
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nullifier: deposit.nullifier,
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secret: deposit.secret,
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pathElements: path_elements,
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pathIndex: path_index,
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}
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console.log('Generating SNARK proof')
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console.time('Proof time')
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const proofData = await websnarkUtils.genWitnessAndProve(groth16, input, circuit, proving_key)
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const { proof, publicSignals } = websnarkUtils.toSolidityInput(proofData)
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console.timeEnd('Proof time')
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console.log('Submitting withdraw transaction')
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await mixer.methods.withdraw(proof, publicSignals).send({ from: (await web3.eth.getAccounts())[0], gas: 4e6 })
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console.log('Done')
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}
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/**
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* Init web3, contracts, and snark
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*/
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async function init() {
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let contractJson, erc20ContractJson, erc20mixerJson
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if (inBrowser) {
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// Initialize using injected web3 (Metamask)
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// To assemble web version run `npm run browserify`
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web3 = new Web3(window.web3.currentProvider, null, { transactionConfirmationBlocks: 1 })
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contractJson = await (await fetch('build/contracts/ETHMixer.json')).json()
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circuit = await (await fetch('build/circuits/withdraw.json')).json()
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proving_key = await (await fetch('build/circuits/withdraw_proving_key.bin')).arrayBuffer()
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MERKLE_TREE_HEIGHT = 16
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ETH_AMOUNT = 1e18
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EMPTY_ELEMENT = 1
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} else {
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// Initialize from local node
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web3 = new Web3('http://localhost:8545', null, { transactionConfirmationBlocks: 1 })
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contractJson = require('./build/contracts/ETHMixer.json')
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circuit = require('./build/circuits/withdraw.json')
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proving_key = fs.readFileSync('build/circuits/withdraw_proving_key.bin').buffer
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require('dotenv').config()
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MERKLE_TREE_HEIGHT = process.env.MERKLE_TREE_HEIGHT
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ETH_AMOUNT = process.env.ETH_AMOUNT
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EMPTY_ELEMENT = process.env.EMPTY_ELEMENT
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ERC20_TOKEN = process.env.ERC20_TOKEN
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erc20ContractJson = require('./build/contracts/ERC20Mock.json')
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erc20mixerJson = require('./build/contracts/ERC20Mixer.json')
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}
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groth16 = await buildGroth16()
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let netId = await web3.eth.net.getId()
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if (contractJson.networks[netId]) {
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const tx = await web3.eth.getTransaction(contractJson.networks[netId].transactionHash)
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mixer = new web3.eth.Contract(contractJson.abi, contractJson.networks[netId].address)
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mixer.deployedBlock = tx.blockNumber
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}
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const tx3 = await web3.eth.getTransaction(erc20mixerJson.networks[netId].transactionHash)
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erc20mixer = new web3.eth.Contract(erc20mixerJson.abi, erc20mixerJson.networks[netId].address)
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erc20mixer.deployedBlock = tx3.blockNumber
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if(ERC20_TOKEN === '') {
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erc20 = new web3.eth.Contract(erc20ContractJson.abi, erc20ContractJson.networks[netId].address)
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const tx2 = await web3.eth.getTransaction(erc20ContractJson.networks[netId].transactionHash)
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erc20.deployedBlock = tx2.blockNumber
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}
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console.log('Loaded')
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}
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// ========== CLI related stuff below ==============
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function printHelp(code = 0) {
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console.log(`Usage:
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Submit a deposit from default eth account and return the resulting note
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$ ./cli.js deposit
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Withdraw a note to 'receiver' account
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$ ./cli.js withdraw <note> <receiver>
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Check address balance
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$ ./cli.js balance <address>
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Example:
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$ ./cli.js deposit
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...
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Your note: 0x1941fa999e2b4bfeec3ce53c2440c3bc991b1b84c9bb650ea19f8331baf621001e696487e2a2ee54541fa12f49498d71e24d00b1731a8ccd4f5f5126f3d9f400
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$ ./cli.js withdraw 0x1941fa999e2b4bfeec3ce53c2440c3bc991b1b84c9bb650ea19f8331baf621001e696487e2a2ee54541fa12f49498d71e24d00b1731a8ccd4f5f5126f3d9f400 0xee6249BA80596A4890D1BD84dbf5E4322eA4E7f0
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`)
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process.exit(code)
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}
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if (inBrowser) {
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window.deposit = deposit
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window.withdraw = async () => {
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const note = prompt('Enter the note to withdraw')
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const receiver = (await web3.eth.getAccounts())[0]
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await withdraw(note, receiver)
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}
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init()
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} else {
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const args = process.argv.slice(2)
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if (args.length === 0) {
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printHelp()
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} else {
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switch (args[0]) {
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case 'deposit':
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if (args.length === 1) {
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init().then(() => deposit()).then(() => process.exit(0)).catch(err => {console.log(err); process.exit(1)})
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}
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else
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printHelp(1)
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break
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case 'depositErc20':
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if (args.length === 1) {
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init().then(() => depositErc20()).then(() => process.exit(0)).catch(err => {console.log(err); process.exit(1)})
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}
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else
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printHelp(1)
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break
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case 'balance':
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if (args.length === 2 && /^0x[0-9a-fA-F]{40}$/.test(args[1])) {
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init().then(() => getBalance(args[1])).then(() => process.exit(0)).catch(err => {console.log(err); process.exit(1)})
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} else
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printHelp(1)
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break
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case 'balanceErc20':
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if (args.length === 3 && /^0x[0-9a-fA-F]{40}$/.test(args[1]) && /^0x[0-9a-fA-F]{40}$/.test(args[2])) {
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init().then(() => getBalanceErc20(args[1], args[2])).then(() => process.exit(0)).catch(err => {console.log(err); process.exit(1)})
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} else
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printHelp(1)
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break
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case 'withdraw':
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if (args.length === 3 && /^0x[0-9a-fA-F]{124}$/.test(args[1]) && /^0x[0-9a-fA-F]{40}$/.test(args[2])) {
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init().then(() => withdraw(args[1], args[2])).then(() => process.exit(0)).catch(err => {console.log(err); process.exit(1)})
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}
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else
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printHelp(1)
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break
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case 'withdrawErc20':
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if (args.length === 4 && /^0x[0-9a-fA-F]{124}$/.test(args[1]) && /^0x[0-9a-fA-F]{40}$/.test(args[2]) && /^0x[0-9a-fA-F]{40}$/.test(args[3])) {
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init().then(() => withdrawErc20(args[1], args[2], args[3])).then(() => process.exit(0)).catch(err => {console.log(err); process.exit(1)})
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}
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else
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printHelp(1)
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break
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case 'test':
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if (args.length === 1) {
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(async () => {
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await init()
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const account = (await web3.eth.getAccounts())[0]
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const note = await deposit()
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await withdraw(note, account)
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const note2 = await deposit()
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await withdraw(note2, account, account)
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process.exit(0)
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})()
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}
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else
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printHelp(1)
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break
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default:
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printHelp(1)
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}
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}
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}
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