MUD

P2P MUD - Decentralized Multi-User Dungeon

A fully decentralized, peer-to-peer text-based multiplayer game with procedural world generation.

Features

• Decentralized Architecture: No central server required. Players connect directly via P2P network using libp2p
• Procedural World Generation: Infinite deterministic world generated from cryptographic seeds
• CRDT State Management: Conflict-free replicated data types ensure consistent state across all peers
• Cryptographic Identity: Ed25519 key pairs for player authentication and action signing
• Classic MUD Gameplay: Text-based interface with movement, combat, items, and exploration

Architecture

┌─────────────────┐
│  Game Client    │
│  (CLI/Web)      │
└────────┬────────┘
         │
┌────────▼────────┐
│  CryptoManager  │── Player keys & signatures
└────────┬────────┘
         │
┌────────▼────────┐     ┌───────────────┐
│  CRDTManager    │◄────┤ WorldGenerator│
│  (Automerge)    │     │ (Procedural)  │
└────────┬────────┘     └───────────────┘
         │
┌────────▼────────┐
│ NetworkManager  │── P2P networking (libp2p)
│  (Gossipsub)    │
└─────────────────┘

Installation

npm install

Usage

npm start

Commands

Movement:

• north / n - Move north
• south / s - Move south
• east / e - Move east
• west / w - Move west
• go <direction> - Move in specified direction

Actions:

• look / l - Look around
• status / s - Show player status
• inventory / i - Show inventory

Items:

• take - Pick up item
• drop <item> - Drop item
• use <item> - Use item

Combat:

• attack - Attack monster

System:

• help - Show help
• peers - Show connected peers
• quit - Exit game

Technology Stack

• Runtime: Node.js (ES Modules)
• P2P Network: libp2p with gossipsub pubsub
• State Sync: Automerge CRDT
• Cryptography: tweetnacl (Ed25519)
• World Gen: seedrandom for deterministic generation

How It Works

1. Player Identity

Each player generates an Ed25519 key pair on first run:

• Public key serves as unique identifier
• Private key signs all actions
• Keys derive seed for procedural generation

2. Procedural World

The world is generated deterministically:

• Each coordinate (x, y) has a unique seed
• Same coordinates always generate same location
• Biomes, monsters, and items are seeded
• World is effectively infinite

3. State Synchronization

Game state syncs via CRDT:

• All actions are signed and broadcast
• Automerge merges concurrent changes
• No conflicts even with offline peers
• State persists as long as one node exists

4. P2P Networking

Libp2p handles networking:

• Gossipsub for message broadcasting
• Automatic peer discovery
• Encrypted connections (Noise protocol)
• No bootstrap dependency after initial connect

Project Structure

src/
├── client/
│   └── index.js          # Main game client & CLI
├── crypto/
│   └── manager.js        # Cryptography & key management
├── world/
│   └── generator.js      # Procedural world generation
├── crdt/
│   └── manager.js        # CRDT state management
└── network/
    └── manager.js        # P2P networking

Development

Run Tests

npm test

Add Bootstrap Nodes

Edit NetworkManager constructor to add bootstrap multiaddrs:

const network = new NetworkManager({
  bootstrapNodes: [
    '/ip4/127.0.0.1/tcp/8080/p2p/Qm...',
  ]
});

Limitations & Future Work

• Currently CLI-only (web client planned)
• Simple combat system (expandable)
• No persistence layer (in-memory only)
• Limited monster/item variety
• No trading between players yet
• No party/group mechanics

License

MIT

Contributing

This is a demonstration of decentralized game architecture. Contributions welcome!

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