feat!: Unique L1 to L2 messages (#9492)

Ensures uniqueness of L1 to L2 messages by mixing in the leaf index into
the content hash. This changes how message hashes are computed. And
since messages are now unique, we can also change how their nullifiers
are computed and _remove_ the message index from them.

**Breaking change:** The structure of the archiver db is changed, so any
existing archiver needs to be wiped out and re-synced.

**Breaking change:** Consuming an L1 to L2 message from private-land now
requires the message index. Good thing is this is how it worked some
time ago and the docs were never updated, so we don't need to change the
docs now!


![image](https://github.com/user-attachments/assets/cc2be4df-11e1-4743-88fb-085c33a50997)

Fixes #9450

l1-contracts/src/core/FeeJuicePortal.sol

@@ -59,12 +59,12 @@ contract FeeJuicePortal is IFeeJuicePortal {
    * @param _to - The aztec address of the recipient
    * @param _amount - The amount to deposit
    * @param _secretHash - The hash of the secret consumable message. The hash should be 254 bits (so it can fit in a Field element)
-   * @return - The key of the entry in the Inbox
+   * @return - The key of the entry in the Inbox and its leaf index
    */
   function depositToAztecPublic(bytes32 _to, uint256 _amount, bytes32 _secretHash)
     external
     override(IFeeJuicePortal)
-    returns (bytes32)
+    returns (bytes32, uint256)
   {
     // Preamble
     address rollup = canonicalRollup();
@@ -80,11 +80,11 @@ contract FeeJuicePortal is IFeeJuicePortal {
     UNDERLYING.safeTransferFrom(msg.sender, address(this), _amount);
 
     // Send message to rollup
-    bytes32 key = inbox.sendL2Message(actor, contentHash, _secretHash);
+    (bytes32 key, uint256 index) = inbox.sendL2Message(actor, contentHash, _secretHash);
 
-    emit DepositToAztecPublic(_to, _amount, _secretHash, key);
+    emit DepositToAztecPublic(_to, _amount, _secretHash, key, index);
 
-    return key;
+    return (key, index);
   }
 
   /**

l1-contracts/src/core/interfaces/IFeeJuicePortal.sol

@@ -6,14 +6,16 @@ import {IERC20} from "@oz/token/ERC20/IERC20.sol";
 import {IRegistry} from "@aztec/governance/interfaces/IRegistry.sol";
 
 interface IFeeJuicePortal {
-  event DepositToAztecPublic(bytes32 indexed to, uint256 amount, bytes32 secretHash, bytes32 key);
+  event DepositToAztecPublic(
+    bytes32 indexed to, uint256 amount, bytes32 secretHash, bytes32 key, uint256 index
+  );
   event FeesDistributed(address indexed to, uint256 amount);
 
   function initialize() external;
   function distributeFees(address _to, uint256 _amount) external;
   function depositToAztecPublic(bytes32 _to, uint256 _amount, bytes32 _secretHash)
     external
-    returns (bytes32);
+    returns (bytes32, uint256);
   function canonicalRollup() external view returns (address);
 
   function UNDERLYING() external view returns (IERC20);

l1-contracts/src/core/interfaces/messagebridge/IInbox.sol

@@ -25,13 +25,13 @@ interface IInbox {
    * @param _recipient - The recipient of the message
    * @param _content - The content of the message (application specific)
    * @param _secretHash - The secret hash of the message (make it possible to hide when a specific message is consumed on L2)
-   * @return The key of the message in the set
+   * @return The key of the message in the set and its leaf index in the tree
    */
   function sendL2Message(
     DataStructures.L2Actor memory _recipient,
     bytes32 _content,
     bytes32 _secretHash
-  ) external returns (bytes32);
+  ) external returns (bytes32, uint256);
   // docs:end:send_l1_to_l2_message
 
   // docs:start:consume

l1-contracts/src/core/libraries/DataStructures.sol

@@ -41,12 +41,14 @@ library DataStructures {
    * @param recipient - The recipient of the message
    * @param content - The content of the message (application specific) padded to bytes32 or hashed if larger.
    * @param secretHash - The secret hash of the message (make it possible to hide when a specific message is consumed on L2).
+   * @param index - Global leaf index on the L1 to L2 messages tree.
    */
   struct L1ToL2Msg {
     L1Actor sender;
     L2Actor recipient;
     bytes32 content;
     bytes32 secretHash;
+    uint256 index;
   }
   // docs:end:l1_to_l2_msg
 

l1-contracts/src/core/libraries/crypto/Hash.sol

@@ -18,7 +18,9 @@ library Hash {
    */
   function sha256ToField(DataStructures.L1ToL2Msg memory _message) internal pure returns (bytes32) {
     return sha256ToField(
-      abi.encode(_message.sender, _message.recipient, _message.content, _message.secretHash)
+      abi.encode(
+        _message.sender, _message.recipient, _message.content, _message.secretHash, _message.index
+      )
     );
   }
 

l1-contracts/src/core/messagebridge/Inbox.sol

@@ -57,13 +57,13 @@ contract Inbox is IInbox {
    * @param _content - The content of the message (application specific)
    * @param _secretHash - The secret hash of the message (make it possible to hide when a specific message is consumed on L2)
    *
-   * @return Hash of the sent message.
+   * @return Hash of the sent message and its leaf index in the tree.
    */
   function sendL2Message(
     DataStructures.L2Actor memory _recipient,
     bytes32 _content,
     bytes32 _secretHash
-  ) external override(IInbox) returns (bytes32) {
+  ) external override(IInbox) returns (bytes32, uint256) {
     require(
       uint256(_recipient.actor) <= Constants.MAX_FIELD_VALUE,
       Errors.Inbox__ActorTooLarge(_recipient.actor)
@@ -81,23 +81,25 @@ contract Inbox is IInbox {
       currentTree = trees[inProgress];
     }
 
+    // this is the global leaf index and not index in the l2Block subtree
+    // such that users can simply use it and don't need access to a node if they are to consume it in public.
+    // trees are constant size so global index = tree number * size + subtree index
+    uint256 index = (inProgress - Constants.INITIAL_L2_BLOCK_NUM) * SIZE + currentTree.nextIndex;
+
     DataStructures.L1ToL2Msg memory message = DataStructures.L1ToL2Msg({
       sender: DataStructures.L1Actor(msg.sender, block.chainid),
       recipient: _recipient,
       content: _content,
-      secretHash: _secretHash
+      secretHash: _secretHash,
+      index: index
     });
 
     bytes32 leaf = message.sha256ToField();
-    // this is the global leaf index and not index in the l2Block subtree
-    // such that users can simply use it and don't need access to a node if they are to consume it in public.
-    // trees are constant size so global index = tree number * size + subtree index
-    uint256 index =
-      (inProgress - Constants.INITIAL_L2_BLOCK_NUM) * SIZE + currentTree.insertLeaf(leaf);
+    currentTree.insertLeaf(leaf);
     totalMessagesInserted++;
     emit MessageSent(inProgress, index, leaf);
 
-    return leaf;
+    return (leaf, index);
   }
 
   /**

l1-contracts/src/mock/MockFeeJuicePortal.sol

@@ -20,8 +20,13 @@ contract MockFeeJuicePortal is IFeeJuicePortal {
 
   function distributeFees(address, uint256) external override {}
 
-  function depositToAztecPublic(bytes32, uint256, bytes32) external pure override returns (bytes32) {
-    return bytes32(0);
+  function depositToAztecPublic(bytes32, uint256, bytes32)
+    external
+    pure
+    override
+    returns (bytes32, uint256)
+  {
+    return (bytes32(0), 0);
   }
 
   function canonicalRollup() external pure override returns (address) {

l1-contracts/test/Inbox.t.sol

@@ -38,15 +38,16 @@ contract InboxTest is Test {
         version: version
       }),
       content: 0x2000000000000000000000000000000000000000000000000000000000000000,
-      secretHash: 0x3000000000000000000000000000000000000000000000000000000000000000
+      secretHash: 0x3000000000000000000000000000000000000000000000000000000000000000,
+      index: 0x01
     });
   }
 
   function _divideAndRoundUp(uint256 a, uint256 b) internal pure returns (uint256) {
     return (a + b - 1) / b;
   }
 
-  function _boundMessage(DataStructures.L1ToL2Msg memory _message)
+  function _boundMessage(DataStructures.L1ToL2Msg memory _message, uint256 _globalLeafIndex)
     internal
     view
     returns (DataStructures.L1ToL2Msg memory)
@@ -61,6 +62,8 @@ contract InboxTest is Test {
     _message.secretHash = bytes32(uint256(_message.secretHash) % Constants.P);
     // update version
     _message.recipient.version = version;
+    // set leaf index
+    _message.index = _globalLeafIndex;
 
     return _message;
   }
@@ -84,32 +87,40 @@ contract InboxTest is Test {
   }
 
   function testFuzzInsert(DataStructures.L1ToL2Msg memory _message) public checkInvariant {
-    DataStructures.L1ToL2Msg memory message = _boundMessage(_message);
+    uint256 globalLeafIndex = (FIRST_REAL_TREE_NUM - 1) * SIZE;
+    DataStructures.L1ToL2Msg memory message = _boundMessage(_message, globalLeafIndex);
 
     bytes32 leaf = message.sha256ToField();
     vm.expectEmit(true, true, true, true);
     // event we expect
-    uint256 globalLeafIndex = (FIRST_REAL_TREE_NUM - 1) * SIZE;
     emit IInbox.MessageSent(FIRST_REAL_TREE_NUM, globalLeafIndex, leaf);
     // event we will get
-    bytes32 insertedLeaf =
+    (bytes32 insertedLeaf, uint256 insertedIndex) =
       inbox.sendL2Message(message.recipient, message.content, message.secretHash);
 
     assertEq(insertedLeaf, leaf);
+    assertEq(insertedIndex, globalLeafIndex);
   }
 
   function testSendDuplicateL2Messages() public checkInvariant {
     DataStructures.L1ToL2Msg memory message = _fakeMessage();
-    bytes32 leaf1 = inbox.sendL2Message(message.recipient, message.content, message.secretHash);
-    bytes32 leaf2 = inbox.sendL2Message(message.recipient, message.content, message.secretHash);
-    bytes32 leaf3 = inbox.sendL2Message(message.recipient, message.content, message.secretHash);
+    (bytes32 leaf1, uint256 index1) =
+      inbox.sendL2Message(message.recipient, message.content, message.secretHash);
+    (bytes32 leaf2, uint256 index2) =
+      inbox.sendL2Message(message.recipient, message.content, message.secretHash);
+    (bytes32 leaf3, uint256 index3) =
+      inbox.sendL2Message(message.recipient, message.content, message.secretHash);
 
     // Only 1 tree should be non-zero
     assertEq(inbox.getNumTrees(), 1);
 
-    // All the leaves should be the same
-    assertEq(leaf1, leaf2);
-    assertEq(leaf2, leaf3);
+    // All the leaves should be different since the index gets mixed in
+    assertNotEq(leaf1, leaf2);
+    assertNotEq(leaf2, leaf3);
+
+    // Check indices
+    assertEq(index1 + 1, index2);
+    assertEq(index1 + 2, index3);
   }
 
   function testRevertIfActorTooLarge() public {
@@ -161,7 +172,8 @@ contract InboxTest is Test {
 
     // We send the messages and then check that toConsume root did not change.
     for (uint256 i = 0; i < _messages.length; i++) {
-      DataStructures.L1ToL2Msg memory message = _boundMessage(_messages[i]);
+      DataStructures.L1ToL2Msg memory message =
+        _boundMessage(_messages[i], inbox.getNextMessageIndex());
 
       // We check whether a new tree is correctly initialized when the one in progress is full
       uint256 numTrees = inbox.getNumTrees();

l1-contracts/test/fee_portal/depositToAztecPublic.t.sol

@@ -77,12 +77,14 @@ contract DepositToAztecPublic is Test {
     bytes32 to = bytes32(0x0);
     bytes32 secretHash = bytes32(uint256(0x01));
     uint256 amount = 100 ether;
+    uint256 expectedIndex = 2 ** Constants.L1_TO_L2_MSG_SUBTREE_HEIGHT;
 
     DataStructures.L1ToL2Msg memory message = DataStructures.L1ToL2Msg({
       sender: DataStructures.L1Actor(address(feeJuicePortal), block.chainid),
       recipient: DataStructures.L2Actor(feeJuicePortal.L2_TOKEN_ADDRESS(), 1 + numberOfRollups),
       content: Hash.sha256ToField(abi.encodeWithSignature("claim(bytes32,uint256)", to, amount)),
-      secretHash: secretHash
+      secretHash: secretHash,
+      index: expectedIndex
     });
 
     bytes32 expectedKey = message.sha256ToField();
@@ -92,16 +94,16 @@ contract DepositToAztecPublic is Test {
 
     Inbox inbox = Inbox(address(Rollup(address(registry.getRollup())).INBOX()));
     assertEq(inbox.totalMessagesInserted(), 0);
-    uint256 index = 2 ** Constants.L1_TO_L2_MSG_SUBTREE_HEIGHT;
 
     vm.expectEmit(true, true, true, true, address(inbox));
-    emit IInbox.MessageSent(2, index, expectedKey);
+    emit IInbox.MessageSent(2, expectedIndex, expectedKey);
     vm.expectEmit(true, true, true, true, address(feeJuicePortal));
-    emit IFeeJuicePortal.DepositToAztecPublic(to, amount, secretHash, expectedKey);
+    emit IFeeJuicePortal.DepositToAztecPublic(to, amount, secretHash, expectedKey, expectedIndex);
 
-    bytes32 key = feeJuicePortal.depositToAztecPublic(to, amount, secretHash);
+    (bytes32 key, uint256 index) = feeJuicePortal.depositToAztecPublic(to, amount, secretHash);
 
     assertEq(inbox.totalMessagesInserted(), 1);
     assertEq(key, expectedKey);
+    assertEq(index, expectedIndex);
   }
 }

l1-contracts/test/fixtures/empty_block_1.json

@@ -8,8 +8,8 @@
     "l2ToL1Messages": []
   },
   "block": {
-    "archive": "0x18589e53843baf9415aa9a4943bd4d8fa19b318329604f51a4ac0b8e7eb8e155",
-    "blockHash": "0x2662dae080808aceafe3377c439d8bea968d5ea74c98643adf5c2ea805f72c0c",
+    "archive": "0x04f48997a6e0472d7919af16c50859f86c041ef9aefceba4be94657943618ac1",
+    "blockHash": "0x2f3394755802dfe8105c0e7a5a7733970b59d83f6b9bd6eb754317f4d6a73c0f",
     "body": "0x00000000",
     "txsEffectsHash": "0x00e994e16b3763fd5039413cf99c2b3c378e2bab939e7992a77bd201b28160d6",
     "decodedHeader": {
@@ -21,12 +21,12 @@
       },
       "globalVariables": {
         "blockNumber": 1,
-        "slotNumber": "0x0000000000000000000000000000000000000000000000000000000000000011",
+        "slotNumber": "0x0000000000000000000000000000000000000000000000000000000000000012",
         "chainId": 31337,
-        "timestamp": 1728563130,
+        "timestamp": 1730234580,
         "version": 1,
-        "coinbase": "0xd498444361455d5099a036e93f395a584cf085c6",
-        "feeRecipient": "0x07c66a9b410a7e26824d677a12d8af977c0db64e5fcdfc8ad704c71c0267d649",
+        "coinbase": "0x2590e3544a7e2e7d736649fefc72ea5ad1d6efc3",
+        "feeRecipient": "0x2146e005e28b76eedc61edeff431b412b5ece74a5818080051832d286795ce2e",
         "gasFees": {
           "feePerDaGas": 0,
           "feePerL2Gas": 0
@@ -57,8 +57,8 @@
         }
       }
     },
-    "header": "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",
-    "publicInputsHash": "0x00e081da850e07688f3b8eac898caaeb80fabf215e1c87bbecc180d88a19f34e",
+    "header": "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",
+    "publicInputsHash": "0x0086289eca84479d5e34db9c4548bdd156af80fb725c51219650aa4460c80240",
     "numTxs": 0
   }
 }

l1-contracts/test/fixtures/empty_block_2.json

@@ -8,8 +8,8 @@
     "l2ToL1Messages": []
   },
   "block": {
-    "archive": "0x1d3dc82359e412945750080a10eede5c3ee3cb9360dc3ca35dda2c5f2e296c52",
-    "blockHash": "0x15fb8c7900432692f9f4e590e6df42d6fff4ce24f0b720514d6bc30ba234d548",
+    "archive": "0x07d7359b2b2922b8126019bef4f2d5698f25226f5f2270a79d1105503727dd6e",
+    "blockHash": "0x1836f56b16db44064b3231102c84c6eaf3327d0204a5171f65b3019fc79c2b5e",
     "body": "0x00000000",
     "txsEffectsHash": "0x00e994e16b3763fd5039413cf99c2b3c378e2bab939e7992a77bd201b28160d6",
     "decodedHeader": {
@@ -21,20 +21,20 @@
       },
       "globalVariables": {
         "blockNumber": 2,
-        "slotNumber": "0x0000000000000000000000000000000000000000000000000000000000000012",
+        "slotNumber": "0x0000000000000000000000000000000000000000000000000000000000000013",
         "chainId": 31337,
-        "timestamp": 1728563154,
+        "timestamp": 1730234604,
         "version": 1,
-        "coinbase": "0xd498444361455d5099a036e93f395a584cf085c6",
-        "feeRecipient": "0x07c66a9b410a7e26824d677a12d8af977c0db64e5fcdfc8ad704c71c0267d649",
+        "coinbase": "0x2590e3544a7e2e7d736649fefc72ea5ad1d6efc3",
+        "feeRecipient": "0x2146e005e28b76eedc61edeff431b412b5ece74a5818080051832d286795ce2e",
         "gasFees": {
           "feePerDaGas": 0,
           "feePerL2Gas": 0
         }
       },
       "lastArchive": {
         "nextAvailableLeafIndex": 2,
-        "root": "0x18589e53843baf9415aa9a4943bd4d8fa19b318329604f51a4ac0b8e7eb8e155"
+        "root": "0x04f48997a6e0472d7919af16c50859f86c041ef9aefceba4be94657943618ac1"
       },
       "stateReference": {
         "l1ToL2MessageTree": {
@@ -57,8 +57,8 @@
         }
       }
     },
-    "header": "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",
-    "publicInputsHash": "0x00815a814be4b3e0ac1a671e1a0321c231ac90e23ef7b2b1e411d32a2fb1948d",
+    "header": "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",
+    "publicInputsHash": "0x009727b9d0f6c22ea711c2e31249776bd687ffa0eaf97b54120af68c96da0eda",
     "numTxs": 0
   }
 }