feat(abstract-utxo): add descriptor signing support for offline vault

modules/abstract-utxo/src/names.ts

@@ -82,6 +82,19 @@ export function getChainFromNetwork(n: utxolib.Network): string {
   }
 }
 
+/**
+ * @param coinName - the name of the coin (e.g. 'btc', 'bch', 'ltc'). Also called 'chain' in some contexts.
+ * @returns the network for a coin. This is the mainnet network for the coin.
+ */
+export function getNetworkFromChain(coinName: string): utxolib.Network {
+  for (const network of utxolib.getNetworkList()) {
+    if (getChainFromNetwork(network) === coinName) {
+      return network;
+    }
+  }
+  throw new Error(`Unknown chain ${coinName}`);
+}
+
 export function getFullNameFromNetwork(n: utxolib.Network): string {
   const name = getNetworkName(n);
 

modules/abstract-utxo/src/offlineVault/OfflineVaultHalfSigned.ts

@@ -0,0 +1,29 @@
+import * as utxolib from '@bitgo/utxo-lib';
+import { BIP32Interface } from '@bitgo/utxo-lib';
+
+import { getNetworkFromChain } from '../names';
+
+import { OfflineVaultUnsigned } from './OfflineVaultUnsigned';
+import { DescriptorTransaction, getHalfSignedPsbt } from './descriptor';
+
+export type OfflineVaultHalfSigned = {
+  halfSigned: { txHex: string };
+};
+
+function createHalfSignedFromPsbt(psbt: utxolib.Psbt): OfflineVaultHalfSigned {
+  return { halfSigned: { txHex: psbt.toHex() } };
+}
+
+export function createHalfSigned(coin: string, prv: string | BIP32Interface, tx: unknown): OfflineVaultHalfSigned {
+  const network = getNetworkFromChain(coin);
+  if (typeof prv === 'string') {
+    prv = utxolib.bip32.fromBase58(prv);
+  }
+  if (!OfflineVaultUnsigned.is(tx)) {
+    throw new Error('unsupported transaction type');
+  }
+  if (DescriptorTransaction.is(tx)) {
+    return createHalfSignedFromPsbt(getHalfSignedPsbt(tx, prv, network));
+  }
+  throw new Error('unsupported transaction type');
+}

modules/abstract-utxo/src/offlineVault/OfflineVaultUnsigned.ts

@@ -0,0 +1,35 @@
+import * as utxolib from '@bitgo/utxo-lib';
+import { Triple } from '@bitgo/sdk-core';
+import * as t from 'io-ts';
+
+export const XPubWithDerivationPath = t.intersection(
+  [t.type({ xpub: t.string }), t.partial({ derivationPath: t.string })],
+  'XPubWithDerivationPath'
+);
+
+export type XPubWithDerivationPath = t.TypeOf<typeof XPubWithDerivationPath>;
+
+/**
+ * This is the transaction payload that is sent to the offline vault to sign.
+ */
+export const OfflineVaultUnsigned = t.type(
+  {
+    xpubsWithDerivationPath: t.type({
+      user: XPubWithDerivationPath,
+      backup: XPubWithDerivationPath,
+      bitgo: XPubWithDerivationPath,
+    }),
+    coinSpecific: t.type({ txHex: t.string }),
+  },
+  'BaseTransaction'
+);
+
+export type OfflineVaultUnsigned = t.TypeOf<typeof OfflineVaultUnsigned>;
+
+type WithXpub = { xpub: string };
+type NamedKeys = { user: WithXpub; backup: WithXpub; bitgo: WithXpub };
+export function toKeyTriple(xpubs: NamedKeys): Triple<utxolib.BIP32Interface> {
+  return [xpubs.user.xpub, xpubs.backup.xpub, xpubs.bitgo.xpub].map((xpub) =>
+    utxolib.bip32.fromBase58(xpub)
+  ) as Triple<utxolib.BIP32Interface>;
+}

modules/abstract-utxo/src/offlineVault/descriptor/index.ts

@@ -0,0 +1 @@
+export * from './transaction';

modules/abstract-utxo/src/offlineVault/descriptor/transaction.ts

@@ -0,0 +1,43 @@
+import * as utxolib from '@bitgo/utxo-lib';
+import * as t from 'io-ts';
+
+import { NamedDescriptor } from '../../descriptor';
+import { OfflineVaultUnsigned, toKeyTriple } from '../OfflineVaultUnsigned';
+import {
+  getValidatorOneOfTemplates,
+  getValidatorSignedByUserKey,
+  getValidatorSome,
+  toDescriptorMapValidate,
+} from '../../descriptor/validatePolicy';
+import { DescriptorMap } from '../../core/descriptor';
+import { signPsbt } from '../../transaction/descriptor';
+
+export const DescriptorTransaction = t.intersection(
+  [OfflineVaultUnsigned, t.type({ descriptors: t.array(NamedDescriptor) })],
+  'DescriptorTransaction'
+);
+
+export type DescriptorTransaction = t.TypeOf<typeof DescriptorTransaction>;
+
+export function getDescriptorsFromDescriptorTransaction(tx: DescriptorTransaction): DescriptorMap {
+  const { descriptors, xpubsWithDerivationPath } = tx;
+  const pubkeys = toKeyTriple(xpubsWithDerivationPath);
+  const policy = getValidatorSome([
+    // allow all 2-of-3-ish descriptors where the keys match the wallet keys
+    getValidatorOneOfTemplates(['Wsh2Of3', 'Wsh2Of3CltvDrop', 'ShWsh2Of3CltvDrop']),
+    // allow all descriptors signed by the user key
+    getValidatorSignedByUserKey(),
+  ]);
+  return toDescriptorMapValidate(descriptors, pubkeys, policy);
+}
+
+export function getHalfSignedPsbt(
+  tx: DescriptorTransaction,
+  prv: utxolib.BIP32Interface,
+  network: utxolib.Network
+): utxolib.Psbt {
+  const psbt = utxolib.bitgo.createPsbtDecode(tx.coinSpecific.txHex, network);
+  const descriptorMap = getDescriptorsFromDescriptorTransaction(tx);
+  signPsbt(psbt, descriptorMap, prv, { onUnknownInput: 'throw' });
+  return psbt;
+}

modules/abstract-utxo/src/offlineVault/index.ts

@@ -0,0 +1,2 @@
+export * as descriptor from './descriptor';
+export * from './OfflineVaultHalfSigned';

modules/abstract-utxo/test/offlineVault/fixtures/Wsh2Of3.buildAdmin.custodial.json

@@ -0,0 +1,73 @@
+{
+  "walletKeys": [
+    "xprv9zXudaVgkhXsjTeXgpJ3K62R6bZDYQ5L5TVYfhGPLDDLNhfLtCYwHm4R4aMnMMeRpHSiM5Krxxbrux7iz99f7rSmZyddtBogiSch4PRVVXZ",
+    "xpub6CYwP1gQmPLwzD67x2nBoxiKquYs2CQExaqyQ3KbcntynZCoUGKErxXNg6Mft3x7r5c1xtHTp827ZRQY7dwUa8XYjQ5RCPUwtTPAe6bSv8b",
+    "xprv9s21ZrQH143K3Kh6W9VDkrpUSDrikEYKbbEKyB5Xn9bJeBPRSRSyWqQ5Fzoujj4eFmRKrxFPipYtfVqyu3aNYH4Lojrdhemi4aUdX8CjD8W"
+  ],
+  "response": {
+    "txBase64": "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",
+    "descriptors": [
+      {
+        "name": "external",
+        "value": "wsh(multi(2,xpub6DXG362ab56Awwiznqq3gDy9edPhwroBSgR9U5fztYkKFVzVRjsBqZNtusyuT3U841NogK9ByRFHz6Zhb5jTGWkiJyu3SVBqKiPFzw2GcyV/0/*,xpub6CYwP1gQmPLwzD67x2nBoxiKquYs2CQExaqyQ3KbcntynZCoUGKErxXNg6Mft3x7r5c1xtHTp827ZRQY7dwUa8XYjQ5RCPUwtTPAe6bSv8b/0/*,xpub661MyMwAqRbcFomZcB2E7zmCzFhD9hGAxp9vmZV9LV8HWyiZyxmE4diZ7EREPnU5XdHjx1w9Xp2o7qtP3mGmWM6SWYD1zGcA2VuU6VEjomd/0/*))#gw7wwcku",
+        "signatures": [],
+        "lastIndex": 1
+      },
+      {
+        "name": "internal",
+        "value": "wsh(multi(2,xpub6DXG362ab56Awwiznqq3gDy9edPhwroBSgR9U5fztYkKFVzVRjsBqZNtusyuT3U841NogK9ByRFHz6Zhb5jTGWkiJyu3SVBqKiPFzw2GcyV/1/*,xpub6CYwP1gQmPLwzD67x2nBoxiKquYs2CQExaqyQ3KbcntynZCoUGKErxXNg6Mft3x7r5c1xtHTp827ZRQY7dwUa8XYjQ5RCPUwtTPAe6bSv8b/1/*,xpub661MyMwAqRbcFomZcB2E7zmCzFhD9hGAxp9vmZV9LV8HWyiZyxmE4diZ7EREPnU5XdHjx1w9Xp2o7qtP3mGmWM6SWYD1zGcA2VuU6VEjomd/1/*))#sw3k4yqr",
+        "signatures": [],
+        "lastIndex": 0
+      }
+    ],
+    "formatVersion": 1,
+    "coin": "btc",
+    "pubs": [
+      "xpub6DXG362ab56Awwiznqq3gDy9edPhwroBSgR9U5fztYkKFVzVRjsBqZNtusyuT3U841NogK9ByRFHz6Zhb5jTGWkiJyu3SVBqKiPFzw2GcyV",
+      "xpub6CYwP1gQmPLwzD67x2nBoxiKquYs2CQExaqyQ3KbcntynZCoUGKErxXNg6Mft3x7r5c1xtHTp827ZRQY7dwUa8XYjQ5RCPUwtTPAe6bSv8b",
+      "xpub661MyMwAqRbcFomZcB2E7zmCzFhD9hGAxp9vmZV9LV8HWyiZyxmE4diZ7EREPnU5XdHjx1w9Xp2o7qtP3mGmWM6SWYD1zGcA2VuU6VEjomd"
+    ],
+    "xpubsWithDerivationPath": {
+      "user": {
+        "xpub": "xpub6DXG362ab56Awwiznqq3gDy9edPhwroBSgR9U5fztYkKFVzVRjsBqZNtusyuT3U841NogK9ByRFHz6Zhb5jTGWkiJyu3SVBqKiPFzw2GcyV",
+        "derivedFromParentWithSeed": "143700591154482"
+      },
+      "backup": {
+        "xpub": "xpub6CYwP1gQmPLwzD67x2nBoxiKquYs2CQExaqyQ3KbcntynZCoUGKErxXNg6Mft3x7r5c1xtHTp827ZRQY7dwUa8XYjQ5RCPUwtTPAe6bSv8b",
+        "derivedFromParentWithSeed": "210593312354420"
+      },
+      "bitgo": {
+        "xpub": "xpub661MyMwAqRbcFomZcB2E7zmCzFhD9hGAxp9vmZV9LV8HWyiZyxmE4diZ7EREPnU5XdHjx1w9Xp2o7qtP3mGmWM6SWYD1zGcA2VuU6VEjomd"
+      }
+    },
+    "walletId": "6788d3cf8eaf7aa1db27d4575218103c",
+    "walletLabel": "UtxoWalletClient",
+    "amount": "199995579",
+    "address": "bc1q9cp8uk0qpal0h4hzrp2gvjy5hmwune773pnp2qtfwap22ryrnuxsehzwgh",
+    "pendingApprovalId": "6788d3cf8eaf7aa1db27d4f563e0e411",
+    "creatorId": "6788d3ce8eaf7aa1db27d18bc5baa93d",
+    "creatorEmail": "[email protected]",
+    "createDate": "2025-01-16T09:39:27.667Z",
+    "enterpriseId": "6788d3ce8eaf7aa1db27d2a664daec54",
+    "enterpriseName": "Foo Enterprises",
+    "enterpriseFeatureFlags": [
+      "enableMMI"
+    ],
+    "videoId": {
+      "approver": "",
+      "date": "",
+      "link": "",
+      "exception": "",
+      "waived": true
+    },
+    "coinSpecific": {
+      "txHex": "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",
+      "inputIds": [
+        "0101010101010101010101010101010101010101010101010101010101010101:0",
+        "0101010101010101010101010101010101010101010101010101010101010101:1"
+      ]
+    },
+    "recipientsInfo": [],
+    "keyDerivationPath": "143700591154482"
+  }
+}

modules/abstract-utxo/test/offlineVault/halfSigned.ts

@@ -0,0 +1,80 @@
+import * as fs from 'fs';
+import assert from 'assert';
+import crypto from 'crypto';
+
+import * as t from 'io-ts';
+import * as utxolib from '@bitgo/utxo-lib';
+
+import { createHalfSigned } from '../../src/offlineVault';
+import { DescriptorTransaction } from '../../src/offlineVault/descriptor';
+
+function getFixturesNames(): string[] {
+  // I'm using sync here because mocha cannot do async setup
+  // eslint-disable-next-line no-sync
+  return fs.readdirSync(__dirname + '/fixtures').filter((f) => f.endsWith('.json'));
+}
+
+const Fixture = t.type({
+  walletKeys: t.array(t.string),
+  response: t.unknown,
+});
+
+type Fixture = t.TypeOf<typeof Fixture>;
+
+async function readFixture(name: string): Promise<Fixture> {
+  const data = JSON.parse(await fs.promises.readFile(__dirname + '/fixtures/' + name, 'utf-8'));
+  if (!Fixture.is(data)) {
+    throw new Error(`Invalid fixture ${name}`);
+  }
+  return data;
+}
+
+function withRotatedXpubs(tx: DescriptorTransaction): DescriptorTransaction {
+  const { user, backup, bitgo } = tx.xpubsWithDerivationPath;
+  return {
+    ...tx,
+    xpubsWithDerivationPath: {
+      user: bitgo,
+      backup: user,
+      bitgo: backup,
+    },
+  };
+}
+
+function withRandomXpubs(tx: DescriptorTransaction) {
+  function randomXpub() {
+    const bytes = crypto.getRandomValues(new Uint8Array(32));
+    return utxolib.bip32.fromSeed(Buffer.from(bytes)).neutered().toBase58();
+  }
+  return {
+    ...tx,
+    xpubsWithDerivationPath: {
+      user: randomXpub(),
+      backup: randomXpub(),
+      bitgo: randomXpub(),
+    },
+  };
+}
+
+function withoutDescriptors(tx: DescriptorTransaction): DescriptorTransaction {
+  return {
+    ...tx,
+    descriptors: [],
+  };
+}
+
+describe('OfflineVaultHalfSigned', function () {
+  for (const fixtureName of getFixturesNames()) {
+    it(`can sign fixture ${fixtureName}`, async function () {
+      const { walletKeys, response } = await readFixture(fixtureName);
+      const prv = utxolib.bip32.fromBase58(walletKeys[0]);
+      createHalfSigned('btc', prv, response);
+
+      assert(DescriptorTransaction.is(response));
+      const mutations = [withRotatedXpubs(response), withRandomXpubs(response), withoutDescriptors(response)];
+      for (const mutation of mutations) {
+        assert.throws(() => createHalfSigned('btc', prv, mutation));
+      }
+    });
+  }
+});