Lightning Network Implementation

Overview

The Lightning Network implementation in anya-core provides a robust second-layer payment protocol built on top of the Bitcoin blockchain. It allows for fast, low-cost transactions without the need to record every transaction on the blockchain, significantly improving scalability for Bitcoin applications.

Architecture

The implementation follows the hexagonal architecture pattern with clear separation of concerns:

                    +---------------------+
                    |   Bitcoin Network   |
                    +----------+----------+
                               |
                               v
+----------------+   +--------------------+   +----------------+
|                |   |                    |   |                |
| Lightning Node +-->| Bitcoin-Lightning  |<--+ Bitcoin Client |
|                |   |       Bridge       |   |                |
+-------+--------+   +--------------------+   +----------------+
        |
+-------v--------+   +--------------------+   +----------------+
|                |   |                    |   |                |
| Payment Router +-->|  Payment Executor  |<--+ Invoice Manager|
|                |   |                    |   |                |
+----------------+   +--------------------+   +----------------+

Core Components

LightningNode

The central component responsible for managing Lightning Network functionality:

  • Channel management
  • Peer connections
  • Invoice creation and payment
  • Transaction signing

BitcoinLightningBridge

Handles the interaction between the Bitcoin blockchain and the Lightning Network:

  • Funding transactions for channels
  • Monitoring blockchain for channel-related transactions
  • Managing channel lifecycle events (opening, closing)
  • Handling on-chain funds for Lightning operations

Channel Management

Channels are the core concept in Lightning Network, allowing parties to transact off-chain:

  • Channel creation with multi-signature wallets
  • Channel state management
  • Balance updates via commitment transactions
  • Channel closure (cooperative and force-close)

Payment Management

Components for handling Lightning payments:

  • Invoice creation and decoding
  • Payment routing
  • Payment execution
  • Multi-hop payments

Usage Examples

Initializing Lightning Components

use anya_core::{AnyaCore, AnyaConfig};

// Create a configuration with Lightning enabled
let mut config = AnyaConfig::default();
config.bitcoin_config.lightning_enabled = true;

// Initialize the system
let anya = AnyaCore::new(config)?;

// Access the Lightning node through the Bitcoin manager
if let Some(bitcoin_manager) = &anya.bitcoin_manager {
    if let Some(lightning_node) = bitcoin_manager.lightning_node() {
        // Now you can use the Lightning Node
        let node_info = lightning_node.get_node_info()?;
        println!("Lightning node pubkey: {}", node_info.pubkey);
    }
}

Opening a Channel

// Connect to a peer
lightning_node.connect_peer("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619", "127.0.0.1", 9735)?;

// Open a channel with the peer
let channel = lightning_node.open_channel(
    "02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619", 
    100_000, // 100,000 satoshis capacity
    Some(10_000 * 1000), // 10,000 satoshis initial push to peer (in millisatoshis)
    false // Public channel
)?;

println!("Opened channel with ID: {}", channel.channel_id);

Creating and Paying Invoices

// Create an invoice
let invoice = lightning_node.create_invoice(
    Some(50_000), // 50,000 millisatoshis
    "Test payment", 
    Some(3600) // 1 hour expiry
)?;

println!("Invoice: {}", invoice.bolt11);

// Pay an invoice
let payment = lightning_node.pay_invoice(&invoice.bolt11, None)?;
println!("Payment sent with ID: {}", payment.payment_id);

Using the Bitcoin-Lightning Bridge

// Create a Bitcoin-Lightning bridge
let bridge = BitcoinLightningBridge::new(Arc::new(lightning_node))?;

// Initialize with current block height
let current_height = bitcoin_manager.get_block_height()?;
bridge.init(current_height)?;

// Create a funding address for a new channel
let address = bridge.create_funding_address(
    "02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619",
    200_000, // 200,000 satoshi channel
    None, // No initial push
    false // Public channel
)?;

println!("Send funds to {} to open the channel", address);

Integration with Bitcoin

The Lightning implementation integrates with the Bitcoin functionality through:

  1. On-chain funding: Using Bitcoin transactions to fund channels
  2. Transaction monitoring: Watching for channel funding and closing transactions
  3. Blockchain verification: Ensuring secure channel operations
  4. Key management: Shared key infrastructure for both on-chain and off-chain operations

Security Considerations

  • Custody: Lightning nodes have hot wallets with private keys
  • Channel backups: Static channel backups to recover funds
  • Watchtowers: Monitoring for malicious channel closures
  • Transaction verification: Proper validation of all channel transactions

Future Enhancements

  • BOLT12 Offers: Support for more flexible payment requests
  • Splicing: Adding/removing funds from channels without closing
  • Multi-part payments: Splitting payments across multiple channels
  • Trampoline routing: Better privacy and routing reliability

Reference

Last updated: 2025-03-01