feat(abstract-utxo): refactor replay protection to use pubkeys

Refactor replay protection to use the public keys directly instead of output
scripts. The output scripts are now derived from the public keys, making the
code more maintainable and easier to understand.

Add tests for replay protection to verify that the output scripts match those
computed from descriptors.

Issue: BTC-2806

Co-authored-by: llm-git <[email protected]>

Author: OttoAllmendinger

modules/abstract-utxo/src/transaction/explainTransaction.ts

@@ -6,7 +6,7 @@ import { getDescriptorMapFromWallet, isDescriptorWallet } from '../descriptor';
 import { toBip32Triple } from '../keychains';
 import { getPolicyForEnv } from '../descriptor/validatePolicy';
 
-import { getReplayProtectionOutputScripts } from './fixedScript/replayProtection';
+import { getReplayProtectionPubkeys } from './fixedScript/replayProtection';
 import type {
   TransactionExplanationUtxolibLegacy,
   TransactionExplanationUtxolibPsbt,
@@ -63,7 +63,7 @@ export function explainTx<TNumber extends number | bigint>(
     }
     return fixedScript.explainPsbtWasm(tx, walletXpubs, {
       replayProtection: {
-        outputScripts: getReplayProtectionOutputScripts(network),
+        publicKeys: getReplayProtectionPubkeys(network),
       },
     });
   } else {

modules/abstract-utxo/src/transaction/fixedScript/explainPsbtWasm.ts

@@ -44,7 +44,7 @@ export function explainPsbtWasm(
   params: {
     replayProtection: {
       checkSignature?: boolean;
-      outputScripts: Buffer[];
+      publicKeys: Buffer[];
     };
     customChangeWalletXpubs?: Triple<string>;
   }

modules/abstract-utxo/src/transaction/fixedScript/replayProtection.ts

@@ -1,23 +1,45 @@
-import * as wasmUtxo from '@bitgo/wasm-utxo';
 import * as utxolib from '@bitgo/utxo-lib';
+import { utxolibCompat } from '@bitgo/wasm-utxo';
 
-export function getReplayProtectionAddresses(network: utxolib.Network): string[] {
+export const pubkeyProd = Buffer.from('0255b9f71ac2c78fffd83e3e37b9e17ae70d5437b7f56d0ed2e93b7de08015aa59', 'hex');
+
+export const pubkeyTestnet = Buffer.from('0219da48412c2268865fe8c126327d1b12eee350a3b69eb09e3323cc9a11828945', 'hex');
+
+export function getReplayProtectionPubkeys(network: utxolib.Network): Buffer[] {
   switch (network) {
     case utxolib.networks.bitcoincash:
     case utxolib.networks.bitcoinsv:
-      return ['33p1q7mTGyeM5UnZERGiMcVUkY12SCsatA'];
-    case utxolib.networks.bitcoincashTestnet:
+      return [pubkeyProd];
     case utxolib.networks.bitcoinsvTestnet:
-      return ['2MuMnPoSDgWEpNWH28X2nLtYMXQJCyT61eY'];
+    case utxolib.networks.bitcoincashTestnet:
+      return [pubkeyTestnet];
   }
-
   return [];
 }
 
-export function getReplayProtectionOutputScripts(network: utxolib.Network): Buffer[] {
-  return getReplayProtectionAddresses(network).map((address) =>
-    Buffer.from(wasmUtxo.utxolibCompat.toOutputScript(address, network))
-  );
+// sh(pk(pubkeyProd))
+// 33p1q7mTGyeM5UnZERGiMcVUkY12SCsatA
+// bitcoincash:pqt5x9w0m6z0f3znjkkx79wl3l7ywrszesemp8xgpf
+const replayProtectionScriptsProd = [Buffer.from('a914174315cfde84f4c45395ac6f15df8ffc470e02cc87', 'hex')];
+// sh(pk(pubkeyTestnet))
+// 2MuMnPoSDgWEpNWH28X2nLtYMXQJCyT61eY
+// bchtest:pqtjmnzwqffkrk2349g3cecfwwjwxusvnq87n07cal
+const replayProtectionScriptsTestnet = [Buffer.from('a914172dcc4e025361d951a9511c670973a4e3720c9887', 'hex')];
+
+export function getReplayProtectionAddresses(
+  network: utxolib.Network,
+  format: 'default' | 'cashaddr' = 'default'
+): string[] {
+  switch (network) {
+    case utxolib.networks.bitcoincash:
+    case utxolib.networks.bitcoinsv:
+      return replayProtectionScriptsProd.map((script) => utxolibCompat.fromOutputScript(script, network, format));
+    case utxolib.networks.bitcoinsvTestnet:
+    case utxolib.networks.bitcoincashTestnet:
+      return replayProtectionScriptsTestnet.map((script) => utxolibCompat.fromOutputScript(script, network, format));
+    default:
+      return [];
+  }
 }
 
 export function isReplayProtectionUnspent<TNumber extends number | bigint>(

modules/abstract-utxo/test/unit/transaction/fixedScript/explainPsbt.ts

@@ -65,7 +65,7 @@ function describeTransactionWith(acidTest: testutil.AcidTest) {
 
       const wasmExplanation = explainPsbtWasm(wasmPsbt, walletXpubs, {
         replayProtection: {
-          outputScripts: [acidTest.getReplayProtectionOutputScript()],
+          publicKeys: [acidTest.getReplayProtectionPublicKey()],
         },
       });
 
@@ -95,7 +95,7 @@ function describeTransactionWith(acidTest: testutil.AcidTest) {
     it('returns custom change outputs when parameter is set', function () {
       const wasmExplanation = explainPsbtWasm(wasmPsbt, walletXpubs, {
         replayProtection: {
-          outputScripts: [acidTest.getReplayProtectionOutputScript()],
+          publicKeys: [acidTest.getReplayProtectionPublicKey()],
         },
         customChangeWalletXpubs,
       });

modules/abstract-utxo/test/unit/transaction/fixedScript/parsePsbt.ts

@@ -134,7 +134,7 @@ function describeParseTransactionWith(
             acidTest.rootWalletKeys.triple.map((k) => k.neutered().toBase58()) as Triple<string>,
             {
               replayProtection: {
-                outputScripts: [acidTest.getReplayProtectionOutputScript()],
+                publicKeys: [acidTest.getReplayProtectionPublicKey()],
               },
             }
           );

modules/abstract-utxo/test/unit/transaction/fixedScript/replayProtection.ts

@@ -0,0 +1,28 @@
+import assert from 'node:assert/strict';
+
+import * as utxolib from '@bitgo/utxo-lib';
+import { Descriptor, utxolibCompat } from '@bitgo/wasm-utxo';
+
+import {
+  getReplayProtectionAddresses,
+  pubkeyProd,
+  pubkeyTestnet,
+} from '../../../../src/transaction/fixedScript/replayProtection';
+
+function createReplayProtectionOutputScript(pubkey: Buffer): Buffer {
+  const descriptor = Descriptor.fromString(`sh(pk(${pubkey.toString('hex')}))`, 'definite');
+  return Buffer.from(descriptor.scriptPubkey());
+}
+
+describe('replayProtection', function () {
+  it('should have scriptPubKeys that match descriptor computation', function () {
+    for (const pubkey of [pubkeyProd, pubkeyTestnet]) {
+      const network = pubkey === pubkeyProd ? utxolib.networks.bitcoincash : utxolib.networks.bitcoincashTestnet;
+      const expectedScript = createReplayProtectionOutputScript(pubkey);
+      const actualAddresses = getReplayProtectionAddresses(network);
+      assert.equal(actualAddresses.length, 1);
+      const actualScript = Buffer.from(utxolibCompat.toOutputScript(actualAddresses[0], network));
+      assert.deepStrictEqual(actualScript, expectedScript);
+    }
+  });
+});