feat(abstract-utxo): optimize tx signing with bulk approach

Use bulk signing for all inputs in one operation instead of signing
each input individually.

Added BulkSigningError class to provide better error reporting
when the bulk signing operation fails.

Issue: BTC-2980

Co-authored-by: llm-git <llm-git@ttll.de>

Author: OttoAllmendinger

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

@@ -28,6 +28,13 @@ export class InputSigningError<TNumber extends number | bigint = number> extends
   }
 }
 
+export class BulkSigningError extends Error {
+  constructor(public reason: Error | string) {
+    const reasonMessage = reason instanceof Error ? reason.message : reason;
+    super(`bulk signing error: ${reasonMessage}`);
+  }
+}
+
 export class TransactionSigningError<TNumber extends number | bigint = number> extends Error {
   constructor(signErrors: InputSigningError<TNumber>[], verifyError: InputSigningError<TNumber>[]) {
     super(

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

@@ -3,7 +3,7 @@ import assert from 'assert';
 import { BIP32Interface } from '@bitgo/utxo-lib';
 import { BIP32, ECPair, fixedScriptWallet } from '@bitgo/wasm-utxo';
 
-import { InputSigningError, TransactionSigningError } from './SigningError';
+import { BulkSigningError, InputSigningError, TransactionSigningError } from './SigningError';
 import { Musig2Participant } from './musig2';
 
 export type ReplayProtectionKeys = {
@@ -29,6 +29,7 @@ function hasKeyPathSpendInput(
 
 /**
  * Sign all inputs of a PSBT and verify signatures after signing.
+ * Uses bulk signing for performance (signs all matching inputs in one pass).
  * Collects and logs signing errors and verification errors, throws error in the end if any of them failed.
  */
 export function signAndVerifyPsbtWasm(
@@ -38,32 +39,24 @@ export function signAndVerifyPsbtWasm(
   replayProtection: ReplayProtectionKeys
 ): fixedScriptWallet.BitGoPsbt {
   const wasmSigner = toWasmBIP32(signerKeychain);
-  const parsed = tx.parseTransactionWithWalletKeys(rootWalletKeys, replayProtection);
 
-  const signErrors: InputSigningError<bigint>[] = [];
+  // Bulk sign all wallet inputs (ECDSA + MuSig2) - much faster than per-input signing
+  try {
+    tx.sign(wasmSigner);
+  } catch (e) {
+    throw new BulkSigningError(e);
+  }
+
+  // Verify signatures for all signed inputs (still per-input for granular error reporting)
+  const parsed = tx.parseTransactionWithWalletKeys(rootWalletKeys, replayProtection);
   const verifyErrors: InputSigningError<bigint>[] = [];
 
-  // Sign all inputs (skipping replay protection inputs)
   parsed.inputs.forEach((input, inputIndex) => {
     if (input.scriptType === 'p2shP2pk') {
       // Skip replay protection inputs - they are platform signed only
       return;
     }
 
-    const outputId = `${input.previousOutput.txid}:${input.previousOutput.vout}`;
-    try {
-      tx.sign(inputIndex, wasmSigner);
-    } catch (e) {
-      signErrors.push(new InputSigningError<bigint>(inputIndex, input.scriptType, { id: outputId }, e));
-    }
-  });
-
-  // Verify signatures for all signed inputs
-  parsed.inputs.forEach((input, inputIndex) => {
-    if (input.scriptType === 'p2shP2pk') {
-      return;
-    }
-
     const outputId = `${input.previousOutput.txid}:${input.previousOutput.vout}`;
     try {
       if (!tx.verifySignature(inputIndex, wasmSigner)) {
@@ -76,8 +69,8 @@ export function signAndVerifyPsbtWasm(
     }
   });
 
-  if (signErrors.length || verifyErrors.length) {
-    throw new TransactionSigningError(signErrors, verifyErrors);
+  if (verifyErrors.length) {
+    throw new TransactionSigningError([], verifyErrors);
   }
 
   return tx;