VERY DRAFT Multisig verifier

l1-contracts/contracts/state-transition/MultisigCommiter.sol

@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.28;
+
+import {Ownable2StepUpgradeable} from "@openzeppelin/contracts-upgradeable-v4/access/Ownable2StepUpgradeable.sol";
+import {LibMap} from "./libraries/LibMap.sol";
+import {IZKChain} from "./chain-interfaces/IZKChain.sol";
+import {TimeNotReached, NotAZKChain} from "../common/L1ContractErrors.sol";
+import {IBridgehub} from "../bridgehub/IBridgehub.sol";
+import {IValidatorTimelock} from "./IValidatorTimelock.sol";
+import {IExecutor} from "./chain-interfaces/IExecutor.sol";
+import {ValidatorTimelock} from "./ValidatorTimelock.sol";
+import {EIP712Upgradeable} from "@openzeppelin/contracts-upgradeable-v4/utils/cryptography/EIP712Upgradeable.sol";
+import {SignatureCheckerUpgradeable} from "@openzeppelin/contracts-upgradeable-v4/utils/cryptography/SignatureCheckerUpgradeable.sol";
+
+
+//TODO proper errors
+//TODO maybe combine with ValidatorTimelock
+contract MultisigCommiter is ValidatorTimelock, EIP712Upgradeable {
+	/// @dev EIP-712 TypeHash for commitBatchesMultisig
+    bytes32 internal constant COMMIT_BATCHES_MULTISIG_TYPEHASH =
+        keccak256("CommitBatchesMultisig(address chainAddress, uint256 processBatchFrom, uint256 processBatchTo, bytes batchData)");
+
+	bytes32 internal constant COMMIT_VERIFIER_ROLE = keccak256("COMMIT_VERIFIER_ROLE");
+
+	mapping(address chainAddress => uint256 signingThreshold) internal signingThreshold;
+
+	constructor(address _bridgehubAddr) ValidatorTimelock(_bridgehubAddr) {}
+
+	//TODO __EIP712_init
+
+    function commitBatchesSharedBridge(
+		address _chainAddress,
+        uint256 _processBatchFrom,
+        uint256 _processBatchTo,
+        bytes calldata _batchData
+	) external override {
+		require(signingThreshold[_chainAddress] == 0, "Chain requires verifiers signatures for commit");
+		_recordBatchCommitment(_chainAddress, _processBatchFrom, _processBatchTo);
+        _propagateToZKChain(_chainAddress);
+	}
+
+	function commitBatchesMultisig(
+        address chainAddress,
+        uint256 _processBatchFrom,
+        uint256 _processBatchTo,
+        bytes calldata _batchData,
+		address[] calldata signers,
+		bytes[] calldata signatures
+    ) external onlyRole(chainAddress, COMMITTER_ROLE) {
+        bytes32 digest = _hashTypedDataV4(keccak256(abi.encode(COMMIT_BATCHES_MULTISIG_TYPEHASH, chainAddress, _processBatchFrom, _processBatchTo, _batchData)));
+
+		_checkSignatures(chainAddress, signers, signatures, digest);
+
+		_recordBatchCommitment(chainAddress, _processBatchFrom, _processBatchTo);
+		// we cannot use _propagateToZKChain here, becouse function signature is altered
+		IExecutor(chainAddress).commitBatchesSharedBridge(chainAddress, _processBatchFrom, _processBatchTo, _batchData);
+    }
+
+	function _checkSignatures(address chainAddress, address[] calldata signers, bytes[] calldata signatures, bytes32 digest) internal view {
+		require(signers.length == signatures.length, "Mismatching signatures length");
+		require(signers.length >= signingThreshold[chainAddress], "Not enough signers");
+
+		// signers must be sorted in order to cheaply validate they are not duplicated
+		address previousSigner = address(0);
+		for (uint256 i = 0; i < signers.length; i++) {
+			require(signers[i] > previousSigner, "Signers must be sorted");
+			require(hasRole(chainAddress, COMMIT_VERIFIER_ROLE, signers[i]), "Invalid signature");
+			require(SignatureCheckerUpgradeable.isValidSignatureNow(signers[i], digest, signatures[i]), "Invalid signature");
+			previousSigner = signers[i];
+		}
+	}
+}

l1-contracts/contracts/state-transition/ValidatorTimelock.sol

@@ -199,7 +199,14 @@ contract ValidatorTimelock is
         uint256 _processBatchFrom,
         uint256 _processBatchTo,
         bytes calldata // _batchData (unused in this specific implementation)
-    ) external onlyRole(_chainAddress, COMMITTER_ROLE) {
+    ) external virtual onlyRole(_chainAddress, COMMITTER_ROLE) {
+        _recordBatchCommitment(_chainAddress, _processBatchFrom, _processBatchTo);
+        _propagateToZKChain(_chainAddress);
+    }
+
+    /// @dev Records the timestamp of batch commitment for the given chain address.
+    /// To be used from `commitBatchesSharedBridge`
+    function _recordBatchCommitment(address _chainAddress, uint256 _processBatchFrom, uint256 _processBatchTo) internal {
         unchecked {
             // This contract is only a temporary solution, that hopefully will be disabled until 2106 year, so...
             // It is safe to cast.
@@ -208,7 +215,6 @@ contract ValidatorTimelock is
                 committedBatchTimestamp[_chainAddress].set(i, timestamp);
             }
         }
-        _propagateToZKChain(_chainAddress);
     }
 
     /// @inheritdoc IValidatorTimelock