DDOS Protection with Blockchain Proxies

TL;DR

Using a blockchain to manage a network of proxies sharing unused bandwidth can significantly mitigate Distributed Denial-of-Service (DDoS) attacks. The distributed nature and incentivised participation make it harder for attackers to overwhelm the system, while legitimate users benefit from faster speeds and increased resilience.

How it Works

1. The Problem: DDoS Attacks

• DDoS attacks flood a server with traffic, making it unavailable.
• Traditional mitigation often involves blocking IPs, which can also block legitimate users.
• Centralised proxies are single points of failure and vulnerable targets.

The Solution: Decentralised Blockchain Proxies

• A blockchain network manages a pool of proxy nodes (users sharing bandwidth).
• Requests are routed through these distributed proxies, masking the origin server’s IP address.
• Incentives (e.g., cryptocurrency rewards) encourage participation and maintain a large proxy network.

Setting up the System

1. Choose a Blockchain Platform

• Ethereum, Polygon, or Solana are popular choices for smart contracts. Consider transaction costs and scalability.
• Select a platform that supports decentralised applications (dApps).

Develop Smart Contracts

• Create a contract to manage proxy node registration.
• Implement logic for distributing requests across available proxies.
• Design a reward system based on bandwidth contribution and successful request handling.

// Example Solidity snippet (simplified)
contract ProxyNetwork {
  mapping(address => uint256) public contributedBandwidth;

  function contributeBandwidth(uint256 amount) public {
    contributedBandwidth[msg.sender] += amount;
  }
}

Build the Proxy Network Application

• Develop a dApp that allows users to register as proxy nodes and contribute bandwidth.
• Implement a routing mechanism that selects proxies based on factors like location, latency, and reputation.
• Integrate with the smart contract for registration and reward distribution.

Deploy the Smart Contracts

• Test thoroughly on a testnet before deploying to the mainnet.
• Ensure sufficient gas limits are set for transactions.

Mitigation Techniques

1. Request Distribution

• Spread incoming requests across a large number of proxies, making it harder to overwhelm any single node.
• Implement rate limiting at the proxy level to prevent abuse.

IP Address Masking

• Hide the origin server’s IP address from attackers by routing traffic through multiple proxies.
• Regularly rotate proxy IPs to further obfuscate the server’s location.

Reputation System

• Track the performance and reliability of each proxy node.
• Reward nodes with good reputations and penalise those with poor performance.
• Use a weighted selection algorithm to favour reliable proxies.

Challenge-Response System

• Implement CAPTCHAs or other challenge-response mechanisms at the proxy level to filter out bot traffic.
• Only allow legitimate users to access the origin server.

Benefits

• Increased Resilience: Distributed nature makes it harder for attackers to take down the system.
• Reduced Costs: Utilises unused bandwidth, potentially lowering infrastructure costs.
• Improved Performance: Proxies can be strategically located to improve response times.
• Enhanced Security: Masking IP addresses and implementing reputation systems improves cyber security.