new feature - invoice

README.md

@@ -57,6 +57,32 @@ Transaction mined in block 17036120
 Done
 ```
 
+### using invoice
+![Invoice user flow](img/invoice.png)
+
+```bash
+node cli.js invoice ETH 0.1 --rpc https://goerli.infura.io/v3/9aa3d95b3bc440fa88ea12eaa4456161  
+Connecting to remote node
+Your remote IP address is xx.xx.xx.xx from xx.
+Your note: tornado-eth-0.1-5-0x1d9771a7b9f8b6c03d33116208ce8db1aa559d33e65d22dd2ff78375fc6b635f930536d2432b4bde0178c72cfc79d6b27023c5d9de60985f186b34c18c00
+Your invoice: tornadoInvoice-eth-0.1-5-0x1b680c7dda0c2dd1b85f0fe126d49b16ed594b3cd6d5114db5f4593877a6b84f
+Backed up deposit note as ./backup-tornado-eth-0.1-5-0x1d9771a7.txt
+Backed up invoice as ./backup-tornadoInvoice-eth-0.1-5-0x1b680c7d.txt
+```
+```bash
+node cli.js payInvoice tornadoInvoice-eth-0.1-5-0x1b680c7dda0c2dd1b85f0fe126d49b16ed594b3cd6d5114db5f4593877a6b84f --rpc https://goerli.infura.io/v3/9aa3d95b3bc440fa88ea12eaa4456161
+Connecting to remote node
+Your remote IP address is xx.xx.xx.xx from xx.
+Tornado contract balance is 823.6 ETH
+Sender account balance is 0.79544229 ETH
+Submitting deposit transaction
+Submitting transaction to the remote node
+View transaction on block explorer https://goerli.etherscan.io/tx/0x6ded443caed8d6f2666841149532c64bee149a9a8e1070ed4c91a12dd1837747
+Tornado contract balance is 823.7 ETH
+Sender account balance is 0.694488819 ETH
+```
+
+
 ### List of public rpc & relayers for withdrawal
 
 Infura API key fetched from https://rpc.info (Same one with Metamask)

cli.js

@@ -157,6 +157,17 @@ async function backupNote({ currency, amount, netId, note, noteString }) {
   }
 }
 
+
+
+async function backupInvoice({ currency, amount, netId, commitmentNote, invoiceString }) {
+  try {
+    await fs.writeFileSync(`./backup-tornadoInvoice-${currency}-${amount}-${netId}-${commitmentNote.slice(0, 10)}.txt`, invoiceString, 'utf8');
+    console.log("Backed up invoice as", `./backup-tornadoInvoice-${currency}-${amount}-${netId}-${commitmentNote.slice(0, 10)}.txt`)
+  } catch (e) {
+    throw new Error('Writing backup note failed:', e)
+  }
+}
+
 /**
  * Make a deposit
  * @param currency Сurrency
@@ -207,6 +218,75 @@ async function deposit({ currency, amount }) {
   return noteString
 }
 
+
+
+/**
+ * create a Invoice
+ * @param currency Сurrency
+ * @param amount Deposit amount
+ */
+async function createInvoice({ currency, amount }) {
+  const deposit = createDeposit({
+    nullifier: rbigint(31),
+    secret: rbigint(31)
+  })
+  const note = toHex(deposit.preimage, 62)
+  const noteString = `tornado-${currency}-${amount}-${netId}-${note}`
+  console.log(`Your note: ${noteString}`)
+
+  const commitmentNote = toHex(deposit.commitment)
+  const invoiceString = `tornadoInvoice-${currency}-${amount}-${netId}-${commitmentNote}`
+  console.log(`Your invoice: ${invoiceString}`)
+
+  await backupNote({ currency, amount, netId, note, noteString })
+  await backupInvoice({ currency, amount, netId, commitmentNote, invoiceString })
+
+  return (noteString, invoiceString)
+}
+
+/**
+ * Make a payment
+ * @param currency Сurrency
+ * @param amount Deposit amount
+ */
+async function payInvoice({ currency, amount, netId, commitmentNote }) {
+  assert(senderAccount != null, 'Error! PRIVATE_KEY not found. Please provide PRIVATE_KEY in .env file if you deposit')
+
+  if (currency === netSymbol.toLowerCase()) {
+    await printETHBalance({ address: tornadoContract._address, name: 'Tornado contract' })
+    await printETHBalance({ address: senderAccount, name: 'Sender account' })
+    const value = isTestRPC ? ETH_AMOUNT : fromDecimals({ amount, decimals: 18 })
+    console.log('Submitting deposit transaction')
+    await generateTransaction(contractAddress, tornado.methods.deposit(tornadoInstance, toHex(commitmentNote), []).encodeABI(), value)
+    await printETHBalance({ address: tornadoContract._address, name: 'Tornado contract' })
+    await printETHBalance({ address: senderAccount, name: 'Sender account' })
+  } else {
+    // a token
+    await printERC20Balance({ address: tornadoContract._address, name: 'Tornado contract' })
+    await printERC20Balance({ address: senderAccount, name: 'Sender account' })
+    const decimals = isTestRPC ? 18 : config.deployments[`netId${netId}`][currency].decimals
+    const tokenAmount = isTestRPC ? TOKEN_AMOUNT : fromDecimals({ amount, decimals })
+    if (isTestRPC) {
+      console.log('Minting some test tokens to deposit')
+      await generateTransaction(erc20Address, erc20.methods.mint(senderAccount, tokenAmount).encodeABI())
+    }
+
+    const allowance = await erc20.methods.allowance(senderAccount, tornado._address).call({ from: senderAccount })
+    console.log('Current allowance is', fromWei(allowance))
+    if (toBN(allowance).lt(toBN(tokenAmount))) {
+      console.log('Approving tokens for deposit')
+      await generateTransaction(erc20Address, erc20.methods.approve(tornado._address, tokenAmount).encodeABI())
+    }
+
+    console.log('Submitting deposit transaction')
+    await generateTransaction(contractAddress, tornado.methods.deposit(tornadoInstance, toHex(commitmentNote), []).encodeABI())
+    await printERC20Balance({ address: tornadoContract._address, name: 'Tornado contract' })
+    await printERC20Balance({ address: senderAccount, name: 'Sender account' })
+  }
+}
+
+
+
 /**
  * Generate merkle tree for a deposit.
  * Download deposit events from the tornado, reconstructs merkle tree, finds our deposit leaf
@@ -847,6 +927,29 @@ function parseNote(noteString) {
   }
 }
 
+/**
+ * Parses Tornado.cash note
+ * @param invoiceString the note
+ */
+function parseInvoice(noteString) {
+  const noteRegex = /tornadoInvoice-(?<currency>\w+)-(?<amount>[\d.]+)-(?<netId>\d+)-0x(?<commitmentNote>[0-9a-fA-F]{64})/g
+  const match = noteRegex.exec(noteString)
+  if (!match) {
+    throw new Error('The note has invalid format')
+  }
+
+  const netId = Number(match.groups.netId)
+  const buf = Buffer.from(match.groups.commitmentNote, 'hex')
+  const commitmentNote = toHex(buf.slice(0, 32))
+
+  return {
+    currency: match.groups.currency,
+    amount: match.groups.amount,
+    netId,
+    commitmentNote
+  }
+}
+
 async function loadDepositData({ amount, currency, deposit }) {
   try {
     const cachedEvents = await fetchEvents({ type: 'deposit', currency, amount })
@@ -1054,6 +1157,29 @@ async function main() {
         await init({ rpc: program.rpc, currency, amount, torPort: program.tor, localMode: program.local })
         await deposit({ currency, amount })
       })
+
+    program
+      .command('invoice <currency> <amount>')
+      .description(
+        'Create invoice of specified currency and amount from default eth account and return the invoice (to pay) and note (to claim). The currency is one of (ETH|DAI|cDAI|USDC|cUSDC|USDT). The amount depends on currency, see config.js file or visit https://tornado.cash.'
+      )
+      .action(async (currency, amount) => {
+        currency = currency.toLowerCase()
+        await init({ rpc: program.rpc, currency, amount, torPort: program.tor, localMode: program.local })
+        await createInvoice({ currency, amount })
+      })
+
+    program
+      .command('payInvoice <invoice>')
+      .description(
+        'pay invoice of specified currency and amount from default eth account. The currency is one of (ETH|DAI|cDAI|USDC|cUSDC|USDT). The amount depends on currency, see config.js file or visit https://tornado.cash.'
+      )
+      .action(async (invoice) => {
+        const { currency, amount, netId, commitmentNote } = parseInvoice(invoice)
+        await init({ rpc: program.rpc, currency, amount, torPort: program.tor, localMode: program.local })
+        await payInvoice({ currency, amount, netId, commitmentNote })
+      })
+
     program
       .command('withdraw <note> <recipient> [ETH_purchase]')
       .description(