ZK implementation on ETH

// Some code
```
 event MessageVerified(
        bytes32 indexed messageHash, 
        bool verified
    );

    event MessageExecuted(
        bytes32 indexed messageHash, 
        address indexed recipient
    );

    // Verifier circuit parameters (placeholder - replace with actual circuit parameters)
    bytes32 public verifierPublicKey;
    uint256 public constant VERIFICATION_KEY_VERSION = 1;

    constructor() Ownable(msg.sender) {
        // Initialize with a default verifier public key
        verifierPublicKey = keccak256(abi.encodePacked("ZK_BRIDGE_INITIAL_KEY"));
    }

    /**
     * Receive a cross-chain message with ZK proof
     * @param sourceChainId Origin chain identifier
     * @param destinationChainId Destination chain identifier
     * @param sender Original message sender
     * @param recipient Message recipient
     * @param payload Message payload
     * @param zkProof Zero-knowledge proof
     */
    function receiveMessage(
        uint256 sourceChainId,
        uint256 destinationChainId,
        address sender,
        address recipient,
        bytes memory payload,
        bytes memory zkProof
    ) external nonReentrant {
        // Generate unique message hash
        bytes32 messageHash = keccak256(
            abi.encodePacked(
                sourceChainId, 
                destinationChainId, 
                sender, 
                recipient, 
                payload
            )
        );

        require(!processedMessages[messageHash], "Message already processed");

        // Store message
        messages[messageHash] = Message({
            messageHash: messageHash,
            sourceChainId: sourceChainId,
            destinationChainId: destinationChainId,
            sender: sender,
            recipient: recipient,
            payload: payload,
            zkProof: zkProof,
            verified: false,
            executed: false
        });

        emit MessageReceived(messageHash, sourceChainId, destinationChainId);
    }

```