init

yarn-project/circuit-types/src/interfaces/pxe.ts

@@ -3,6 +3,7 @@ import {
   type CompleteAddress,
   type Fq,
   type Fr,
+  type L1_TO_L2_MSG_TREE_HEIGHT,
   type PartialAddress,
   type Point,
 } from '@aztec/circuits.js';
@@ -19,6 +20,7 @@ import { type L2Block } from '../l2_block.js';
 import { type GetUnencryptedLogsResponse, type L1EventPayload, type LogFilter } from '../logs/index.js';
 import { type IncomingNotesFilter } from '../notes/incoming_notes_filter.js';
 import { type ExtendedNote, type OutgoingNotesFilter, type UniqueNote } from '../notes/index.js';
+import { type SiblingPath } from '../sibling_path/sibling_path.js';
 import { type NoteProcessorStats } from '../stats/stats.js';
 import { type SimulatedTx, type Tx, type TxHash, type TxReceipt } from '../tx/index.js';
 import { type TxEffect } from '../tx_effect.js';
@@ -239,6 +241,12 @@ export interface PXE {
    */
   getIncomingNotes(filter: IncomingNotesFilter): Promise<UniqueNote[]>;
 
+  getL1ToL2MembershipWitness(
+    contractAddress: AztecAddress,
+    messageHash: Fr,
+    secret: Fr,
+  ): Promise<[bigint, SiblingPath<typeof L1_TO_L2_MSG_TREE_HEIGHT>] | undefined>;
+
   /**
    * Gets outgoing notes of accounts registered in this PXE based on the provided filter.
    * @param filter - The filter to apply to the notes.

yarn-project/cli/src/cmds/pxe/get_l1_to_l2_message_witness.ts

@@ -0,0 +1,25 @@
+import { type AztecAddress, type Fr, createCompatibleClient } from '@aztec/aztec.js';
+import { type DebugLogger, type LogFn } from '@aztec/foundation/log';
+
+export async function getL1ToL2MessageWitness(
+  rpcUrl: string,
+  contractAddress: AztecAddress,
+  messageHash: Fr,
+  secret: Fr,
+  debugLogger: DebugLogger,
+  log: LogFn,
+) {
+  const client = await createCompatibleClient(rpcUrl, debugLogger);
+  const messageWitness = await client.getL1ToL2MembershipWitness(contractAddress, messageHash, secret);
+
+  log(
+    messageWitness === undefined
+      ? `
+    L1 to L2 Message not found.
+    `
+      : `
+    L1 to L2 message index: ${messageWitness[0]}
+    L1 to L2 message sibling path: ${messageWitness[1]}
+    `,
+  );
+}

yarn-project/cli/src/cmds/pxe/index.ts

@@ -7,6 +7,7 @@ import {
   logJson,
   parseAztecAddress,
   parseEthereumAddress,
+  parseField,
   parseFieldFromHexString,
   parseOptionalAztecAddress,
   parseOptionalInteger,
@@ -165,6 +166,18 @@ export function injectCommands(program: Command, log: LogFn, debugLogger: DebugL
       await blockNumber(options.rpcUrl, debugLogger, log);
     });
 
+  program
+    .command('get-l1-to-l2-message-witness')
+    .description('Gets a L1 to L2 message witness.')
+    .requiredOption('-ca, --contract-address <address>', 'Aztec address of the contract.', parseAztecAddress)
+    .requiredOption('--message-hash <messageHash>', 'The message hash.', parseField)
+    .requiredOption('-secret <secret>', 'The secret used to claim the L1 to L2 message', parseField)
+    .addOption(pxeOption)
+    .action(async ({ contractAddress, messageHash, secret, rpcUrl }) => {
+      const { getL1ToL2MessageWitness } = await import('./get_l1_to_l2_message_witness.js');
+      await getL1ToL2MessageWitness(rpcUrl, contractAddress, messageHash, secret, debugLogger, log);
+    });
+
   program
     .command('get-node-info')
     .description('Gets the information of an aztec node at a URL.')

yarn-project/pxe/src/pxe_service/pxe_service.ts

@@ -17,6 +17,7 @@ import {
   type PXE,
   type PXEInfo,
   type PrivateKernelProver,
+  type SiblingPath,
   SimulatedTx,
   SimulationError,
   TaggedLog,
@@ -32,11 +33,12 @@ import {
 import {
   AztecAddress,
   type CompleteAddress,
+  type L1_TO_L2_MSG_TREE_HEIGHT,
   type PartialAddress,
   computeContractClassId,
   getContractClassFromArtifact,
 } from '@aztec/circuits.js';
-import { computeNoteHashNonce, siloNullifier } from '@aztec/circuits.js/hash';
+import { computeL1ToL2MessageNullifier, computeNoteHashNonce, siloNullifier } from '@aztec/circuits.js/hash';
 import {
   type ContractArtifact,
   type DecodedReturn,
@@ -56,6 +58,7 @@ import { getCanonicalMultiCallEntrypointAddress } from '@aztec/protocol-contract
 import {
   type AcirSimulator,
   type ExecutionResult,
+  MessageLoadOracleInputs,
   accumulateReturnValues,
   collectEnqueuedPublicFunctionCalls,
   collectPublicTeardownFunctionCall,
@@ -355,6 +358,35 @@ export class PXEService implements PXE {
     return Promise.all(extendedNotes);
   }
 
+  async getL1ToL2MembershipWitness(
+    contractAddress: AztecAddress,
+    messageHash: Fr,
+    secret: Fr,
+  ): Promise<[bigint, SiblingPath<typeof L1_TO_L2_MSG_TREE_HEIGHT>] | undefined> {
+    let nullifierIndex: bigint | undefined;
+    let messageIndex = 0n;
+    let startIndex = 0n;
+    let siblingPath: SiblingPath<typeof L1_TO_L2_MSG_TREE_HEIGHT>;
+
+    // We iterate over messages until we find one whose nullifier is not in the nullifier tree --> we need to check
+    // for nullifiers because messages can have duplicates.
+    do {
+      const response = await this.node.getL1ToL2MessageMembershipWitness('latest', messageHash, startIndex);
+      if (!response) {
+        throw new Error(`No non-nullified L1 to L2 message found for message hash ${messageHash.toString()}`);
+      }
+      [messageIndex, siblingPath] = response;
+
+      const messageNullifier = computeL1ToL2MessageNullifier(contractAddress, messageHash, secret, messageIndex);
+
+      nullifierIndex = await this.node.findLeafIndex('latest', MerkleTreeId.NULLIFIER_TREE, messageNullifier);
+
+      startIndex = messageIndex + 1n;
+    } while (nullifierIndex !== undefined);
+
+    return [messageIndex, siblingPath];
+  }
+
   public async addNote(note: ExtendedNote, scope?: AztecAddress) {
     const owner = await this.db.getCompleteAddress(note.owner);
     if (!owner) {