Relayer Network

The IU2U Protocol relies on a decentralized relayer network to facilitate secure cross-chain communication and token transfers between different blockchain networks.

Overview

The relayer network serves as the bridge infrastructure that monitors events on source chains, validates cross-chain transactions, and executes corresponding actions on destination chains. This decentralized approach ensures security, reliability, and censorship resistance.

Architecture

Relayer Roles

1. Event Monitoring

Relayers continuously monitor supported blockchains for cross-chain events:

class EventMonitor {
    constructor(config) {
        this.provider = new ethers.JsonRpcProvider(config.rpc);
        this.gateway = new ethers.Contract(config.gatewayAddress, gatewayABI, this.provider);
        this.blockConfirmations = config.blockConfirmations;
    }

    async monitorEvents() {
        this.gateway.on("ContractCall", async (sender, destinationChain, contractAddress, payloadHash, payload, event) => {
            await this.processEvent({
                type: "CONTRACT_CALL",
                sourceChain: this.chainName,
                txHash: event.transactionHash,
                logIndex: event.logIndex,
                sender,
                destinationChain,
                contractAddress,
                payloadHash,
                payload
            });
        });

        this.gateway.on("ContractCallWithToken", async (sender, destinationChain, contractAddress, payloadHash, payload, symbol, amount, event) => {
            await this.processEvent({
                type: "CONTRACT_CALL_WITH_TOKEN",
                sourceChain: this.chainName,
                txHash: event.transactionHash,
                logIndex: event.logIndex,
                sender,
                destinationChain,
                contractAddress,
                payloadHash,
                payload,
                symbol,
                amount
            });
        });
    }
}

2. Transaction Validation

Each relayer independently validates cross-chain transactions:

class TransactionValidator {
    async validateTransaction(event) {
        // Check block confirmations
        const currentBlock = await this.provider.getBlockNumber();
        const eventBlock = event.blockNumber;
        
        if (currentBlock - eventBlock < this.blockConfirmations) {
            return { valid: false, reason: "Insufficient confirmations" };
        }

        // Verify event authenticity
        const receipt = await this.provider.getTransactionReceipt(event.txHash);
        const eventLog = receipt.logs.find(log => 
            log.logIndex === event.logIndex && 
            log.transactionHash === event.txHash
        );

        if (!eventLog) {
            return { valid: false, reason: "Event not found" };
        }

        // Validate payload hash
        const computedHash = ethers.keccak256(event.payload);
        if (computedHash !== event.payloadHash) {
            return { valid: false, reason: "Payload hash mismatch" };
        }

        // Check for replay attacks
        const commandId = this.generateCommandId(event.txHash, event.logIndex);
        if (await this.isCommandExecuted(commandId)) {
            return { valid: false, reason: "Command already executed" };
        }

        return { valid: true };
    }
}

3. Command Signing

Valid transactions are signed by relayers using their private keys:

class CommandSigner {
    constructor(privateKey) {
        this.wallet = new ethers.Wallet(privateKey);
    }

    async signCommand(event) {
        const commandId = this.generateCommandId(event.txHash, event.logIndex);
        
        const commandData = ethers.AbiCoder.defaultAbiCoder().encode([
            'bytes32',  // commandId
            'string',   // sourceChain
            'string',   // sourceAddress
            'bytes32',  // payloadHash
            'bytes'     // payload
        ], [
            commandId,
            event.sourceChain,
            event.sender,
            event.payloadHash,
            event.payload
        ]);

        const messageHash = ethers.keccak256(commandData);
        const signature = await this.wallet.signMessage(ethers.getBytes(messageHash));
        
        return {
            commandId,
            signature,
            signer: this.wallet.address
        };
    }
}

4. Command Execution

Once sufficient signatures are collected, commands are executed on destination chains:

class CommandExecutor {
    async executeCommand(command, signatures) {
        // Verify minimum signature threshold
        if (signatures.length < this.minSignatures) {
            throw new Error("Insufficient signatures");
        }

        // Prepare execution data
        const executionData = ethers.AbiCoder.defaultAbiCoder().encode([
            'bytes32',     // commandId
            'string',      // sourceChain
            'string',      // sourceAddress
            'bytes',       // payload
            'bytes32[]',   // signatures
            'address[]'    // signers
        ], [
            command.commandId,
            command.sourceChain,
            command.sourceAddress,
            command.payload,
            signatures.map(s => s.signature),
            signatures.map(s => s.signer)
        ]);

        // Execute on destination chain
        const gateway = new ethers.Contract(
            this.getGatewayAddress(command.destinationChain),
            gatewayABI,
            this.getSigner(command.destinationChain)
        );

        const tx = await gateway.execute(executionData);
        const receipt = await tx.wait();

        return receipt;
    }
}

Security Model

Multi-Signature Validation

The network requires multiple relayer signatures for each cross-chain operation:

contract RelayerManager {
    mapping(address => bool) public isRelayer;
    uint256 public minSignatures;
    uint256 public relayerCount;
    
    function validateSignatures(
        bytes32 commandId,
        bytes32[] memory signatures,
        address[] memory signers
    ) public view returns (bool) {
        require(signatures.length >= minSignatures, "Insufficient signatures");
        require(signatures.length == signers.length, "Signature count mismatch");
        
        bytes32 messageHash = keccak256(abi.encode(commandId));
        uint256 validSignatures = 0;
        
        for (uint256 i = 0; i < signatures.length; i++) {
            if (isRelayer[signers[i]] && _verifySignature(messageHash, signatures[i], signers[i])) {
                validSignatures++;
            }
        }
        
        return validSignatures >= minSignatures;
    }
}

Stake-Based Security

Relayers must stake IU2U tokens to participate in the network:

contract RelayerStaking {
    struct RelayerInfo {
        uint256 stake;
        uint256 rewards;
        uint256 penalties;
        bool isActive;
        uint256 joinedAt;
    }
    
    mapping(address => RelayerInfo) public relayers;
    uint256 public minimumStake = 10000 ether; // 10,000 IU2U
    uint256 public slashingAmount = 1000 ether; // 1,000 IU2U
    
    function stakeAsRelayer(uint256 amount) external {
        require(amount >= minimumStake, "Insufficient stake");
        
        IU2U.transferFrom(msg.sender, address(this), amount);
        
        relayers[msg.sender] = RelayerInfo({
            stake: amount,
            rewards: 0,
            penalties: 0,
            isActive: true,
            joinedAt: block.timestamp
        });
        
        emit RelayerStaked(msg.sender, amount);
    }
    
    function slashRelayer(address relayer, string memory reason) external onlyGovernance {
        require(relayers[relayer].isActive, "Relayer not active");
        
        uint256 slashAmount = min(relayers[relayer].stake, slashingAmount);
        relayers[relayer].stake -= slashAmount;
        relayers[relayer].penalties += slashAmount;
        
        if (relayers[relayer].stake < minimumStake) {
            relayers[relayer].isActive = false;
        }
        
        emit RelayerSlashed(relayer, slashAmount, reason);
    }
}

Performance Monitoring

The network monitors relayer performance and availability:

class RelayerMonitor {
    constructor() {
        this.performanceMetrics = new Map();
    }

    trackEventProcessing(relayerAddress, eventId, processingTime, success) {
        if (!this.performanceMetrics.has(relayerAddress)) {
            this.performanceMetrics.set(relayerAddress, {
                totalEvents: 0,
                successfulEvents: 0,
                averageProcessingTime: 0,
                uptime: 0
            });
        }

        const metrics = this.performanceMetrics.get(relayerAddress);
        metrics.totalEvents++;
        
        if (success) {
            metrics.successfulEvents++;
        }

        // Update average processing time
        metrics.averageProcessingTime = (
            (metrics.averageProcessingTime * (metrics.totalEvents - 1)) + processingTime
        ) / metrics.totalEvents;

        this.performanceMetrics.set(relayerAddress, metrics);
    }

    getRelayerScore(relayerAddress) {
        const metrics = this.performanceMetrics.get(relayerAddress);
        if (!metrics) return 0;

        const successRate = metrics.successfulEvents / metrics.totalEvents;
        const speedScore = Math.max(0, 1 - (metrics.averageProcessingTime / 300000)); // 5 min baseline
        
        return (successRate * 0.7) + (speedScore * 0.3);
    }
}

Relayer Operations

Running a Relayer Node

Hardware Requirements

Component	Minimum	Recommended
CPU	4 cores	8 cores
RAM	8 GB	16 GB
Storage	100 GB SSD	500 GB SSD
Network	100 Mbps	1 Gbps
Uptime	95%	99.9%

Software Setup

# Clone relayer software
git clone https://github.com/DINetworks/IU2U-Relayer.git
cd IU2U-Relayer

# Install dependencies
npm install

# Configure relayer
cp config.example.json config.json
# Edit config.json with your settings

# Generate relayer keypair
npm run generate-keys

# Start relayer
npm start

Configuration Example

{
  "relayer": {
    "address": "0x742d35Cc6aB8C0532FdA5c5F8E71c1e4bF7dc789",
    "privateKey": "0x...",
    "stake": "50000000000000000000000"
  },
  "chains": {
    "ethereum": {
      "rpc": "wss://mainnet.infura.io/ws/v3/YOUR_PROJECT_ID",
      "chainId": 1,
      "gatewayAddress": "0x...",
      "blockConfirmations": 12,
      "gasPrice": "20000000000"
    },
    "bsc": {
      "rpc": "wss://bsc-ws-node.nariox.org:443",
      "chainId": 56,
      "gatewayAddress": "0x...",
      "blockConfirmations": 3,
      "gasPrice": "5000000000"
    }
  },
  "monitoring": {
    "enabled": true,
    "metricsPort": 9090,
    "healthCheckPort": 8080
  }
}

Economic Incentives

Reward Distribution

Relayers earn rewards for successful cross-chain operations:

contract RelayerRewards {
    uint256 public constant REWARD_PER_EXECUTION = 1 ether; // 1 IU2U
    uint256 public constant BONUS_MULTIPLIER = 150; // 1.5x for fast execution
    
    function distributeRewards(
        address[] memory executingRelayers,
        uint256 executionTime,
        uint256 averageExecutionTime
    ) external {
        uint256 baseReward = REWARD_PER_EXECUTION / executingRelayers.length;
        
        for (uint256 i = 0; i < executingRelayers.length; i++) {
            uint256 reward = baseReward;
            
            // Bonus for fast execution
            if (executionTime < averageExecutionTime) {
                reward = (reward * BONUS_MULTIPLIER) / 100;
            }
            
            relayers[executingRelayers[i]].rewards += reward;
            IU2U.mint(executingRelayers[i], reward);
            
            emit RewardDistributed(executingRelayers[i], reward);
        }
    }
}

Fee Structure

Operation Type	Base Fee	Relayer Share
Token Transfer	0.1%	80%
Contract Call	0.05%	80%
Complex Execution	0.15%	80%

Governance

Relayer Selection

New relayers are admitted through a governance process:

contract RelayerGovernance {
    struct RelayerProposal {
        address candidate;
        uint256 proposedStake;
        uint256 votesFor;
        uint256 votesAgainst;
        uint256 deadline;
        bool executed;
    }
    
    function proposeRelayer(address candidate, uint256 stake) external {
        require(IU2U.balanceOf(candidate) >= stake, "Insufficient balance");
        
        uint256 proposalId = nextProposalId++;
        proposals[proposalId] = RelayerProposal({
            candidate: candidate,
            proposedStake: stake,
            votesFor: 0,
            votesAgainst: 0,
            deadline: block.timestamp + 7 days,
            executed: false
        });
        
        emit RelayerProposed(proposalId, candidate, stake);
    }
    
    function voteOnProposal(uint256 proposalId, bool support) external {
        require(relayers[msg.sender].isActive, "Only active relayers can vote");
        
        RelayerProposal storage proposal = proposals[proposalId];
        require(block.timestamp <= proposal.deadline, "Voting period ended");
        
        uint256 votingPower = relayers[msg.sender].stake;
        
        if (support) {
            proposal.votesFor += votingPower;
        } else {
            proposal.votesAgainst += votingPower;
        }
        
        emit VoteCast(proposalId, msg.sender, support, votingPower);
    }
}

Network Health

Monitoring Dashboard

Real-time network health metrics:

class NetworkHealthMonitor {
    async getNetworkHealth() {
        const metrics = {
            activeRelayers: await this.getActiveRelayerCount(),
            totalStake: await this.getTotalStakedAmount(),
            averageResponseTime: await this.getAverageResponseTime(),
            successRate: await this.getSuccessRate(),
            pendingTransactions: await this.getPendingTransactionCount()
        };

        return {
            ...metrics,
            healthScore: this.calculateHealthScore(metrics),
            status: this.getNetworkStatus(metrics)
        };
    }

    calculateHealthScore(metrics) {
        const relayerScore = Math.min(metrics.activeRelayers / 10, 1); // Target: 10+ relayers
        const stakeScore = Math.min(metrics.totalStake / 1000000, 1); // Target: 1M IU2U
        const responseScore = Math.max(0, 1 - (metrics.averageResponseTime / 300)); // Target: <5 min
        const successScore = metrics.successRate;

        return (relayerScore * 0.3) + (stakeScore * 0.2) + (responseScore * 0.3) + (successScore * 0.2);
    }
}

Alert System

Automated alerts for network issues:

class AlertSystem {
    constructor() {
        this.thresholds = {
            minActiveRelayers: 3,
            maxResponseTime: 600, // 10 minutes
            minSuccessRate: 0.95
        };
    }

    async checkAlerts() {
        const health = await this.healthMonitor.getNetworkHealth();

        if (health.activeRelayers < this.thresholds.minActiveRelayers) {
            this.sendAlert({
                level: 'CRITICAL',
                message: `Only ${health.activeRelayers} active relayers remaining`,
                action: 'RECRUIT_RELAYERS'
            });
        }

        if (health.averageResponseTime > this.thresholds.maxResponseTime) {
            this.sendAlert({
                level: 'WARNING',
                message: `Average response time: ${health.averageResponseTime}s`,
                action: 'OPTIMIZE_PERFORMANCE'
            });
        }

        if (health.successRate < this.thresholds.minSuccessRate) {
            this.sendAlert({
                level: 'CRITICAL',
                message: `Success rate dropped to ${health.successRate * 100}%`,
                action: 'INVESTIGATE_FAILURES'
            });
        }
    }
}

Future Enhancements

Planned Improvements

1. Zero-Knowledge Proofs: Enhanced privacy for relayer operations

2. Optimistic Execution: Faster finality with fraud proofs

3. Cross-Chain Staking: Stake tokens on one chain, operate on another

4. Dynamic Pricing: Adaptive fee structure based on network congestion

Research Areas

• Relayer Randomization: Random selection for enhanced security

• MEV Protection: Preventing maximal extractable value attacks

• Formal Verification: Mathematical proofs of relayer network security

• Interoperability Standards: Adoption of cross-chain communication protocols

Resources

• Cross-Chain Architecture

• Security Model

• Relayer Setup Guide

• Network Monitoring