feat(fast-inbox): introduce inboxRollingHash end to end, dual with inHash (A-1373)

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

@@ -27,6 +27,11 @@ struct PublicInputArgs {
   bytes32 previousArchive;
   bytes32 endArchive;
   bytes32 outHash;
+  // Inbox rolling-hash chain segment consumed across the proven epoch (AZIP-22 Fast Inbox). Deliberately UNVALIDATED
+  // until the Fast Inbox flip, when they get checked against per-checkpoint records written at propose; for now they
+  // are only passed through to the proof's public inputs.
+  bytes32 previousInboxRollingHash;
+  bytes32 endInboxRollingHash;
   address proverId;
 }
 

l1-contracts/src/core/libraries/rollup/EpochProofLib.sol

@@ -109,6 +109,8 @@ library EpochProofLib {
 
     Epoch endEpoch = assertAcceptable(_args.start, _args.end);
 
+    // Rehash the supplied headers against storage once, here: the public-input assembly below reads the fee
+    // recipient/value out of them and relies on this call having run.
     verifyHeaders(_args.start, _args.end, _args.headers);
 
     // Verify attestations for the last checkpoint in the epoch
@@ -150,6 +152,11 @@ library EpochProofLib {
    * own public inputs used for generating the proof vs the ones assembled
    * by this contract when verifying it.
    *
+   * @dev The fee recipient/value public inputs are sourced from the supplied headers, so this entry point rehashes
+   * them against storage before assembling: an off-chain caller must not walk away with public inputs built from
+   * unverified fee fields and only discover the mismatch when the on-chain proof reverts. The submit path verifies
+   * the headers up front and assembles via computeEpochProofPublicInputs to avoid rehashing them twice.
+   *
    * @param  _start - The start of the epoch (inclusive)
    * @param  _end - The end of the epoch (inclusive)
    * @param  _args - Array of public inputs to the proof (previousArchive, endArchive, endTimestamp, outHash, proverId)
@@ -163,6 +170,107 @@ library EpochProofLib {
     ProposedHeader[] calldata _headers,
     bytes calldata _blobPublicInputs
   ) internal view returns (bytes32[] memory) {
+    verifyHeaders(_start, _end, _headers);
+    return computeEpochProofPublicInputs(_start, _end, _args, _headers, _blobPublicInputs);
+  }
+
+  /**
+   * @notice Verifies committee attestations for the last checkpoint in the epoch before accepting the epoch proof
+   *
+   * @dev This verification ensures that the committee has properly validated the final state of the epoch
+   *      before the proof can be accepted. The function validates that:
+   *      1. The provided attestations match the stored attestation hash for the checkpoint
+   *      2. The attestations have valid signatures from committee members
+   *      3. The attestations meet the required threshold (2/3+ of committee)
+   *
+   *      For escape hatch epochs, attestation verification is skipped since there is no committee
+   *      involvement - only the designated escape hatch proposer can propose blocks.
+   *
+   * @dev Errors Thrown:
+   *      - Rollup__InvalidAttestations: Provided attestations don't match stored hash or fail validation
+   *
+   * @param _endCheckpointNumber The last checkpoint number in the epoch to verify attestations for
+   * @param _attestations The committee attestations containing signatures and validator information
+   */
+  function verifyLastCheckpointAttestationsAndOutHash(
+    uint256 _endCheckpointNumber,
+    CommitteeAttestations memory _attestations,
+    bytes32 _outHash
+  ) private {
+    // Get the stored attestation hash and payload digest for the last checkpoint
+    CompressedTempCheckpointLog storage checkpointLog = STFLib.getStorageTempCheckpointLog(_endCheckpointNumber);
+
+    // Verify that the out hash matches the stored value
+    // The stored out hash is part of the payloadDigest that was attested to.
+    require(checkpointLog.outHash == _outHash, Errors.Rollup__InvalidOutHash(checkpointLog.outHash, _outHash));
+
+    // Verify that the provided attestations match the stored hash
+    bytes32 providedAttestationsHash = keccak256(abi.encode(_attestations));
+    require(providedAttestationsHash == checkpointLog.attestationsHash, Errors.Rollup__InvalidAttestations());
+
+    // Get the epoch for the last checkpoint
+    Epoch epoch = STFLib.getEpochForCheckpoint(_endCheckpointNumber);
+
+    // Check if this is an escape hatch epoch - skip attestation verification if so
+    // since escape hatch blocks are proposed without committee attestations.
+    // Uses epoch-stable lookup so proof verification uses the escape hatch that was
+    // active when the epoch started, not whatever is currently configured.
+    {
+      IEscapeHatch escapeHatch = ValidatorSelectionLib.getEscapeHatchForEpoch(epoch);
+      if (address(escapeHatch) != address(0)) {
+        (bool isOpen,) = escapeHatch.isHatchOpen(epoch);
+        if (isOpen) {
+          // Skip attestation verification for escape hatch epochs
+          return;
+        }
+      }
+    }
+
+    ValidatorSelectionLib.verifyAttestations(epoch, _attestations, checkpointLog.payloadDigest);
+  }
+
+  /**
+   * @notice Rehashes each provided checkpoint header and requires it to match the stored header hash
+   *
+   * @param _start The first checkpoint number in the epoch (inclusive)
+   * @param _end The last checkpoint number in the epoch (inclusive)
+   * @param _headers The proposed headers for each checkpoint in [_start, _end]
+   */
+  function verifyHeaders(uint256 _start, uint256 _end, ProposedHeader[] calldata _headers) private view {
+    uint256 numCheckpoints = _end - _start + 1;
+    require(
+      _headers.length == numCheckpoints, Errors.Rollup__InvalidCheckpointHeaderCount(numCheckpoints, _headers.length)
+    );
+
+    for (uint256 i = 0; i < numCheckpoints; i++) {
+      bytes32 expectedHeaderHash = STFLib.getHeaderHash(_start + i);
+      bytes32 providedHeaderHash = ProposedHeaderLib.hash(_headers[i]);
+      require(
+        providedHeaderHash == expectedHeaderHash,
+        Errors.Rollup__InvalidCheckpointHeader(expectedHeaderHash, providedHeaderHash)
+      );
+    }
+  }
+
+  /**
+   * @notice Assembles the root rollup public inputs, taking the supplied checkpoint headers as already verified
+   *
+   * @dev Callers must have rehashed `_headers` against the stored header hashes beforehand, since the fee
+   * recipient/value public inputs are read straight out of them.
+   *
+   * @param  _start - The start of the epoch (inclusive)
+   * @param  _end - The end of the epoch (inclusive)
+   * @param  _args - Array of public inputs to the proof (previousArchive, endArchive, endTimestamp, outHash, proverId)
+   * @param  _headers - The proposed checkpoint headers supplying the fee recipient and value for each checkpoint
+   * @param _blobPublicInputs- The blob public inputs for the proof
+   */
+  function computeEpochProofPublicInputs(
+    uint256 _start,
+    uint256 _end,
+    PublicInputArgs calldata _args,
+    ProposedHeader[] calldata _headers,
+    bytes calldata _blobPublicInputs
+  ) private view returns (bytes32[] memory) {
     RollupStore storage rollupStore = STFLib.getStorage();
 
     {
@@ -191,6 +299,8 @@ library EpochProofLib {
     //   previous_archive_root: Field,
     //   end_archive_root: Field,
     //   out_hash: Field,
+    //   previous_inbox_rolling_hash: Field,
+    //   end_inbox_rolling_hash: Field,
     //   checkpointHeaderHashes: [Field; Constants.MAX_CHECKPOINTS_PER_EPOCH],
     //   fees: [FeeRecipient; Constants.MAX_CHECKPOINTS_PER_EPOCH],
     //   chain_id: Field,
@@ -208,15 +318,21 @@ library EpochProofLib {
       publicInputs[1] = _args.endArchive;
 
       publicInputs[2] = _args.outHash;
+
+      // Inbox rolling-hash chain segment consumed across the epoch (AZIP-22 Fast Inbox). Deliberately UNVALIDATED
+      // until the Fast Inbox flip, when they get checked against per-checkpoint records written at propose; for now
+      // they are only passed through to the proof's public inputs.
+      publicInputs[3] = _args.previousInboxRollingHash;
+      publicInputs[4] = _args.endInboxRollingHash;
     }
 
     uint256 numCheckpoints = _end - _start + 1;
 
     for (uint256 i = 0; i < numCheckpoints; i++) {
-      publicInputs[3 + i] = STFLib.getHeaderHash(_start + i);
+      publicInputs[5 + i] = STFLib.getHeaderHash(_start + i);
     }
 
-    uint256 offset = 3 + Constants.MAX_CHECKPOINTS_PER_EPOCH;
+    uint256 offset = 5 + Constants.MAX_CHECKPOINTS_PER_EPOCH;
 
     // Taking recipient/value from the checkpoint headers rather than the prover
     // as defense in depth. Slots past numCheckpoints stay zero.
@@ -276,84 +392,6 @@ library EpochProofLib {
     return publicInputs;
   }
 
-  /**
-   * @notice Verifies committee attestations for the last checkpoint in the epoch before accepting the epoch proof
-   *
-   * @dev This verification ensures that the committee has properly validated the final state of the epoch
-   *      before the proof can be accepted. The function validates that:
-   *      1. The provided attestations match the stored attestation hash for the checkpoint
-   *      2. The attestations have valid signatures from committee members
-   *      3. The attestations meet the required threshold (2/3+ of committee)
-   *
-   *      For escape hatch epochs, attestation verification is skipped since there is no committee
-   *      involvement - only the designated escape hatch proposer can propose blocks.
-   *
-   * @dev Errors Thrown:
-   *      - Rollup__InvalidAttestations: Provided attestations don't match stored hash or fail validation
-   *
-   * @param _endCheckpointNumber The last checkpoint number in the epoch to verify attestations for
-   * @param _attestations The committee attestations containing signatures and validator information
-   */
-  function verifyLastCheckpointAttestationsAndOutHash(
-    uint256 _endCheckpointNumber,
-    CommitteeAttestations memory _attestations,
-    bytes32 _outHash
-  ) private {
-    // Get the stored attestation hash and payload digest for the last checkpoint
-    CompressedTempCheckpointLog storage checkpointLog = STFLib.getStorageTempCheckpointLog(_endCheckpointNumber);
-
-    // Verify that the out hash matches the stored value
-    // The stored out hash is part of the payloadDigest that was attested to.
-    require(checkpointLog.outHash == _outHash, Errors.Rollup__InvalidOutHash(checkpointLog.outHash, _outHash));
-
-    // Verify that the provided attestations match the stored hash
-    bytes32 providedAttestationsHash = keccak256(abi.encode(_attestations));
-    require(providedAttestationsHash == checkpointLog.attestationsHash, Errors.Rollup__InvalidAttestations());
-
-    // Get the epoch for the last checkpoint
-    Epoch epoch = STFLib.getEpochForCheckpoint(_endCheckpointNumber);
-
-    // Check if this is an escape hatch epoch - skip attestation verification if so
-    // since escape hatch blocks are proposed without committee attestations.
-    // Uses epoch-stable lookup so proof verification uses the escape hatch that was
-    // active when the epoch started, not whatever is currently configured.
-    {
-      IEscapeHatch escapeHatch = ValidatorSelectionLib.getEscapeHatchForEpoch(epoch);
-      if (address(escapeHatch) != address(0)) {
-        (bool isOpen,) = escapeHatch.isHatchOpen(epoch);
-        if (isOpen) {
-          // Skip attestation verification for escape hatch epochs
-          return;
-        }
-      }
-    }
-
-    ValidatorSelectionLib.verifyAttestations(epoch, _attestations, checkpointLog.payloadDigest);
-  }
-
-  /**
-   * @notice Rehashes each provided checkpoint header and requires it to match the stored header hash
-   *
-   * @param _start The first checkpoint number in the epoch (inclusive)
-   * @param _end The last checkpoint number in the epoch (inclusive)
-   * @param _headers The proposed headers for each checkpoint in [_start, _end]
-   */
-  function verifyHeaders(uint256 _start, uint256 _end, ProposedHeader[] calldata _headers) private view {
-    uint256 numCheckpoints = _end - _start + 1;
-    require(
-      _headers.length == numCheckpoints, Errors.Rollup__InvalidCheckpointHeaderCount(numCheckpoints, _headers.length)
-    );
-
-    for (uint256 i = 0; i < numCheckpoints; i++) {
-      bytes32 expectedHeaderHash = STFLib.getHeaderHash(_start + i);
-      bytes32 providedHeaderHash = ProposedHeaderLib.hash(_headers[i]);
-      require(
-        providedHeaderHash == expectedHeaderHash,
-        Errors.Rollup__InvalidCheckpointHeader(expectedHeaderHash, providedHeaderHash)
-      );
-    }
-  }
-
   /**
    * @notice Validates that an epoch proof submission meets all acceptance criteria
    *
@@ -421,6 +459,9 @@ library EpochProofLib {
    *      2. Assembling the public inputs for the root rollup circuit
    *      3. Verifying the validity proof against the assembled public inputs using the configured verifier
    *
+   * @dev Assumes the caller has already verified the supplied checkpoint headers against storage, so assembly skips
+   *      rehashing them.
+   *
    * @dev Errors Thrown:
    *      - Rollup__InvalidBlobProof: Batched blob proof verification failed
    *      - Rollup__InvalidProof: validity proof verification failed
@@ -436,7 +477,7 @@ library EpochProofLib {
     BlobLib.validateBatchedBlob(_args.blobInputs);
 
     bytes32[] memory publicInputs =
-      getEpochProofPublicInputs(_args.start, _args.end, _args.args, _args.headers, _args.blobInputs);
+      computeEpochProofPublicInputs(_args.start, _args.end, _args.args, _args.headers, _args.blobInputs);
 
     require(rollupStore.config.epochProofVerifier.verify(_args.proof, publicInputs), Errors.Rollup__InvalidProof());
 

l1-contracts/src/core/libraries/rollup/ProposedHeaderLib.sol

@@ -22,6 +22,7 @@ struct ProposedHeader {
   bytes32 blockHeadersHash;
   bytes32 blobsHash;
   bytes32 inHash;
+  bytes32 inboxRollingHash;
   bytes32 outHash;
   Slot slotNumber;
   Timestamp timestamp;
@@ -56,6 +57,7 @@ library ProposedHeaderLib {
         _header.blockHeadersHash,
         _header.blobsHash,
         _header.inHash,
+        _header.inboxRollingHash,
         _header.outHash,
         _header.slotNumber,
         Timestamp.unwrap(_header.timestamp).toUint64(),

l1-contracts/test/Rollup.t.sol

@@ -12,7 +12,7 @@ import {Registry} from "@aztec/governance/Registry.sol";
 import {Inbox} from "@aztec/core/messagebridge/Inbox.sol";
 import {Outbox} from "@aztec/core/messagebridge/Outbox.sol";
 import {Errors} from "@aztec/core/libraries/Errors.sol";
-import {ProposedHeader} from "@aztec/core/libraries/rollup/ProposedHeaderLib.sol";
+import {ProposedHeader, ProposedHeaderLib} from "@aztec/core/libraries/rollup/ProposedHeaderLib.sol";
 
 import {
   IRollupCore,
@@ -874,6 +874,52 @@ contract RollupTest is RollupBase {
     assertEq(outbox.getRootData(Epoch.wrap(0), 2), outHash2, "Root at K=2 should be outHash2");
   }
 
+  // getEpochProofPublicInputs is the view that the prover-publisher calls off-chain to validate its inputs before
+  // submitting. Because the fee recipient/value public inputs are taken from the supplied headers, the header check
+  // must run here too - not only on the submit path - so a mismatch is caught before publishing rather than reverting
+  // on-chain.
+  function testGetEpochProofPublicInputsVerifiesHeaders() public setUpFor("empty_checkpoint_1") {
+    _proposeCheckpoint("empty_checkpoint_1", 1);
+
+    DecoderBase.Data memory data = load("empty_checkpoint_1").checkpoint;
+    CheckpointLog memory checkpoint = rollup.getCheckpoint(0);
+
+    PublicInputArgs memory args = PublicInputArgs({
+      previousArchive: checkpoint.archive,
+      endArchive: data.archive,
+      outHash: data.header.outHash,
+      previousInboxRollingHash: 0,
+      endInboxRollingHash: data.header.inboxRollingHash,
+      proverId: address(0)
+    });
+
+    ProposedHeader[] memory headers = new ProposedHeader[](1);
+    headers[0] = proposedHeaders[1];
+
+    // With the canonical header, the getter assembles the public inputs, sourcing the fee recipient/value from the
+    // header.
+    bytes32[] memory publicInputs = rollup.getEpochProofPublicInputs(1, 1, args, headers, data.batchedBlobInputs);
+    assertEq(publicInputs.length, Constants.ROOT_ROLLUP_PUBLIC_INPUTS_LENGTH, "Unexpected public inputs length");
+
+    uint256 feesOffset = 5 + Constants.MAX_CHECKPOINTS_PER_EPOCH;
+    assertEq(
+      publicInputs[feesOffset], bytes32(uint256(uint160(headers[0].coinbase))), "Coinbase not sourced from header"
+    );
+    assertEq(
+      publicInputs[feesOffset + 1], bytes32(headers[0].accumulatedFees), "Accumulated fees not sourced from header"
+    );
+
+    // Tamper a fee field so the header no longer hashes to the stored value; the getter must reject it.
+    bytes32 expectedHeaderHash = ProposedHeaderLib.hash(headers[0]);
+    headers[0].accumulatedFees += 1;
+    bytes32 providedHeaderHash = ProposedHeaderLib.hash(headers[0]);
+
+    vm.expectRevert(
+      abi.encodeWithSelector(Errors.Rollup__InvalidCheckpointHeader.selector, expectedHeaderHash, providedHeaderHash)
+    );
+    rollup.getEpochProofPublicInputs(1, 1, args, headers, data.batchedBlobInputs);
+  }
+
   function _submitEpochProof(
     uint256 _start,
     uint256 _end,
@@ -895,7 +941,12 @@ contract RollupTest is RollupBase {
     address _prover
   ) internal {
     PublicInputArgs memory args = PublicInputArgs({
-      previousArchive: _prevArchive, endArchive: _archive, outHash: _outHash, proverId: _prover
+      previousArchive: _prevArchive,
+      endArchive: _archive,
+      outHash: _outHash,
+      previousInboxRollingHash: 0,
+      endInboxRollingHash: 0,
+      proverId: _prover
     });
 
     uint256 size = _end - _start + 1;

l1-contracts/test/base/DecoderBase.sol

@@ -47,6 +47,7 @@ contract DecoderBase is TestBase {
     bytes32 feeRecipient;
     GasFees gasFees;
     bytes32 inHash;
+    bytes32 inboxRollingHash;
     bytes32 lastArchiveRoot;
     bytes32 outHash;
     uint256 slotNumber;
@@ -104,6 +105,7 @@ contract DecoderBase is TestBase {
           blockHeadersHash: full.checkpoint.header.blockHeadersHash,
           blobsHash: full.checkpoint.header.blobsHash,
           inHash: full.checkpoint.header.inHash,
+          inboxRollingHash: full.checkpoint.header.inboxRollingHash,
           outHash: full.checkpoint.header.outHash,
           slotNumber: Slot.wrap(full.checkpoint.header.slotNumber),
           timestamp: Timestamp.wrap(full.checkpoint.header.timestamp),

l1-contracts/test/base/RollupBase.sol

@@ -78,6 +78,8 @@ contract RollupBase is DecoderBase {
       previousArchive: parentCheckpointLog.archive,
       endArchive: endFull.checkpoint.archive,
       outHash: endFull.checkpoint.header.outHash,
+      previousInboxRollingHash: 0,
+      endInboxRollingHash: 0,
       proverId: _prover
     });