Bitcoin SPV, Funding Proof and Electrum Client

.gitignore

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+node_modules/
+*.code-workspace

client/.eslintrc

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+{
+  "extends": "eslint-config-keep",
+  "parserOptions": {
+    "ecmaVersion": 2017,
+    "sourceType": "module"
+  },
+  "env": {
+    "es6": true,
+    "mocha": true
+  },
+  "rules": {
+    "semi": [
+      2,
+      "never"
+    ]
+  }
+}

client/config/config.json

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+{
+    "electrum": {
+        "testnet": {
+            "server": "electrumx-server.tbtc.svc.cluster.local",
+            "port": 50002,
+            "protocol": "tls"
+        }
+    }
+}

client/package.json

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+{
+    "name": "tbtc-client",
+    "version": "0.0.1",
+    "description": "",
+    "scripts": {
+        "test": "CONFIG_FILE=${npm_package_config_file} mocha --timeout 5000",
+        "js:lint": "eslint .",
+        "js:lint:fix": "eslint --fix ."
+    },
+    "config": {
+        "file": "./config/config.json"
+    },
+    "author": "Jakub Nowakowski <[email protected]>",
+    "license": "ISC",
+    "dependencies": {
+        "tbtc-helpers": "file:../lib/tbtc-helpers"
+    },
+    "devDependencies": {
+        "chai": "^4.2.0",
+        "fs": "0.0.1-security",
+        "mocha": "^6.2.0",
+        "rewire": "^4.0.1",
+        "eslint": "^5.16.0",
+        "eslint-config-keep": "git+https://github.com/keep-network/eslint-config-keep.git#0.2.0"
+    }
+}

client/src/Deposit.js

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+// PAGE 1: MAKE A DEPOSIT
+async function createDeposit() {
+  // TODO: Implement:
+  // Call the deposit factory to get a new deposit
+  // return the deposit address.
+}
+
+// PAGE 2: PUT A BOND
+async function initializeDeposit(depositAddress) {
+  // TODO: Implement:
+  // 1. Call deposit to create new keep
+  // 2. Watch for ECDSAKeepCreated event from ECDSAKeepFactory contract
+  // 3. call get public key
+}

client/src/FundingProof.js

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+const BitcoinTxParser = require('tbtc-helpers').BitcoinTxParser
+const bitcoinSPV = require('tbtc-helpers').BitcoinSPV
+const ElectrumClient = require('tbtc-helpers').ElectrumClient
+
+const fs = require('fs')
+
+/**
+ * Reads electrum client configuration details from a config file.
+ * @param {string} configFilePath Path to the configuration file.
+ * @return {ElectrumClient.Config} Electrum client configuration.
+ */
+function readElectrumConfig(configFilePath) {
+  const configFile = fs.readFileSync(configFilePath, 'utf8')
+  config = JSON.parse(configFile)
+
+  return new ElectrumClient.Config(
+    config.electrum.testnet.server,
+    config.electrum.testnet.port,
+    config.electrum.testnet.protocol
+  )
+}
+
+const electrumConfig = readElectrumConfig(process.env.CONFIG_FILE)
+
+/**
+ * Gets transaction SPV proof from BitcoinSPV.
+ * @param {string} txID Transaction ID
+ * @param {number} confirmations Required number of confirmations
+ */
+async function getTransactionProof(txID, confirmations) {
+  bitcoinSPV.initialize(electrumConfig)
+
+  const spvProof = await bitcoinSPV.getTransactionProof(txID, confirmations)
+    .catch((err) => {
+      bitcoinSPV.close()
+      return Promise.reject(new Error(`failed to get bitcoin spv proof: ${err}`))
+    })
+
+  bitcoinSPV.close()
+
+  return {
+    merkleProof: spvProof.merkleProof,
+    txInBlockIndex: spvProof.txInBlockIndex,
+    chainHeaders: spvProof.chainHeaders,
+  }
+}
+
+// PAGE 5: Submit Proof
+// 1. Get transaction proof
+// 2. Submit proof to tBTC
+
+/**
+ * Calculates deposit funding proof and submits it to tBTC.
+ * @param {string} txID Funding transaction ID.
+ * @param {number} fundingOutputIndex Position of a funding output in the transaction.
+ */
+async function calculateAndSubmitFundingProof(txID, fundingOutputIndex) {
+  if (txID.length != 64) {
+    return Promise.reject(
+      new Error(`invalid transaction id length [${txID.length}], required: [64]`)
+    )
+  }
+
+  // TODO: We need to calculate confirmations value in a special way:
+  // See: https://github.com/keep-network/tbtc-dapp/pull/8#discussion_r307438648
+  const confirmations = 6
+
+  const spvProof = await getTransactionProof(electrumConfig, txID, confirmations)
+
+  // 2. Parse transaction to get required details.
+  const txDetails = await BitcoinTxParser.parse(spvProof.tx)
+    .cath((err) => {
+      return Promise.reject(new Error(`failed to parse spv proof: ${err}`))
+    })
+
+  // 3. Submit proof to the contracts
+  // version: txDetails.version,
+  // txInVector: txDetails.txInVector,
+  // txOutVector: txDetails.txOutVector,
+  // fundingOutputIndex: fundingOutputIndex,
+  // locktime: txDetails.locktime,
+  // merkleProof: spvProof.merkleProof,
+  // txInBlockIndex: spvProof.txInBlockIndex,
+  // chainHeaders: spvProof.chainHeaders,
+
+
+  // return eth transaction id to later convert it to etherscan link
+}
+
+module.exports = {
+  calculateAndSubmitFundingProof,
+}

client/src/FundingTransaction.js

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+// PAGE 3: Pay BTC
+async function getAddress(depositAddress) {
+  // TODO: Implement:
+  // 1. Get keep public key from the deposit
+  // 2. Calculate P2WPKH address from the key
+}
+
+// Transition from PAGE 3 to PAGE 4
+// 1. Wait for transaction on chain
+// 2. Return transaction ID
+async function getFundingTransactionID(electrumConfig, bitcoinAddress) {
+  // TODO: Implement
+}
+
+// PAGE 4. WAITING FOR CONFIRMATIONS
+async function waitForConfirmations(transactionID) {
+  // TODO: Implement:
+  // 1. Wait for required number of confirmations for the transaction
+  // 2. Monitor confirmations on the chain and return when ready
+}
+
+module.exports = {
+  getAddress, getFundingTransactionID, waitForConfirmations,
+}

client/test/FundingProofTest.js

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+const rewire = require('rewire')
+const FundingProof = rewire('../src/FundingProof')
+
+const fs = require('fs')
+const chai = require('chai')
+const assert = chai.assert
+
+const TX_ID = '72e7fd57c2adb1ed2305c4247486ff79aec363296f02ec65be141904f80d214e'
+const CONFIRMATIONS = 6
+
+describe('FundingProof', async () => {
+  it('getTransactionProof', async () => {
+    const proofFile = fs.readFileSync('./test/data/proof.json', 'utf8')
+    const expectedResult = JSON.parse(proofFile)
+
+    const result = await FundingProof.__get__('getTransactionProof')(TX_ID, CONFIRMATIONS)
+
+    assert.deepEqual(result, expectedResult)
+  })
+})

client/test/data/proof.json

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+{
+    "merkleProof": "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",
+    "txInBlockIndex": 177,
+    "chainHeaders": "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"
+}

lib/tbtc-helpers/.eslintrc

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+{
+  "extends": "eslint-config-keep",
+  "parserOptions": {
+    "ecmaVersion": 2017,
+    "sourceType": "module"
+  },
+  "env": {
+    "es6": true,
+    "mocha": true
+  },
+  "rules": {
+    "semi": [
+      2,
+      "never"
+    ]
+  }
+}

lib/tbtc-helpers/index.js

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+const BitcoinSPV = require('./src/BitcoinSPV')
+const BitcoinTxParser = require('./src/BitcoinTxParser')
+const ElectrumClient = require('./src/ElectrumClient')
+
+module.exports = {
+  BitcoinSPV, BitcoinTxParser, ElectrumClient
+}