diff --git a/modules/utxo-lib/src/testutil/psbt.ts b/modules/utxo-lib/src/testutil/psbt.ts
index 23fe79033f..07e5d128aa 100644
--- a/modules/utxo-lib/src/testutil/psbt.ts
+++ b/modules/utxo-lib/src/testutil/psbt.ts
@@ -201,7 +201,7 @@ export function constructPsbt(
     if (isWalletUnspent(u) && cosignerName) {
       addWalletUnspentToPsbt(psbt, u, rootWalletKeys, signerName, cosignerName, { skipNonWitnessUtxo });
     } else {
-      const { redeemScript } = createOutputScriptP2shP2pk(rootWalletKeys[signerName].publicKey);
+      const { redeemScript } = createOutputScriptP2shP2pk(rootWalletKeys.user.publicKey);
       assert(redeemScript);
       addReplayProtectionUnspentToPsbt(psbt, u, redeemScript, { skipNonWitnessUtxo });
     }
@@ -328,6 +328,12 @@ export class AcidTest {
     return `${networkName} ${this.signStage} ${this.txFormat}`;
   }
 
+  getReplayProtectionOutputScript(): Buffer {
+    const { scriptPubKey } = createOutputScriptP2shP2pk(this.rootWalletKeys.user.publicKey);
+    assert(scriptPubKey);
+    return scriptPubKey;
+  }
+
   createPsbt(): UtxoPsbt {
     const psbt = constructPsbt(this.inputs, this.outputs, this.network, this.rootWalletKeys, this.signStage, {
       deterministic: true,