La-Vak (ละแวก)

Secure, Zero-Configuration P2P File Synchronization for the Local Neighborhood.

La-Vak (Thai: ละแวก - /la.wɛ̂ːk/) is a high-performance, decentralized file transfer protocol built for high-trust environments. By eliminating reliance on centralized cloud infrastructure, La-Vak ensures that sensitive data remains within the physical boundaries of your local network (LAN) while providing a modern, reactive user experience.

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📋 Overview

Developed as part of the Data Encryption curriculum (Course 02204352), La-Vak implements a hybrid cryptographic architecture to solve the "Local Discovery Problem" without sacrificing data integrity or confidentiality.

Key Pillars

• Zero-Config Discovery (Neighborhood Names): Instant peer identification via UDP Multicast (mDNS-inspired) using friendly "Animal Names" for easy recognition.
• Privacy-by-Design: End-to-End Encryption (E2EE) with no external metadata leakage.
• Cross-Platform Accessibility: A "Reactive Web" approach that bridges Desktop performance with Mobile browser convenience.

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🏗 System Architecture

The system utilizes a Hybrid P2P Engine to bypass browser-based networking limitations:

Component	Responsibility	Technology Stack
Core Engine	L2/L3 Networking, Cryptography, File I/O	Node.js (CommonJS)
Dashboard	Reactive UI/UX, State Management	React, TypeScript, Vite
Protocol	Peer Discovery & Health Checks	UDP Multicast (Port 41234)
Transport	High-speed Binary Data Streaming	TCP Sockets / TLS

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🔒 Security Specifications

La-Vak adheres to the strictly defined security requirements of the 02204352 Data Encryption project:

1. Cryptographic Suite

• Symmetric Encryption: AES-256 in GCM (Galois/Counter Mode) for authenticated encryption, providing both confidentiality and built-in integrity verification.
• Asymmetric Handshake: RSA-4096 for secure session key exchange between untrusted peers.
• Hashing: SHA-256 for pre-transfer and post-transfer bit-level verification.

2. Threat Mitigation

• MITM Protection: Hybrid encryption ensures that passive listeners on the Wi-Fi cannot decrypt traffic.
• Tamper Detection: The GCM Auth Tag prevents unauthorized modification of data during transit.
• Isolation: Operates strictly on the Local Subnet; no WAN/Internet exit points.

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📂 Project Structure

la-vak/
├── client/           # Frontend Dashboard (React + TS)
├── server/           # Backend Engine (Discovery & Crypto Logic)
│   ├── discovery.js  # [P1] Peer Discovery Protocol
│   ├── security.js   # [P3] Cryptographic Implementations
│   ├── names.js      # [P0] Animal Name Generator
│   └── index.js      # [P4] Orchestration & API Layer
└── doc/              # Academic Requirements & System Diagrams

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🚀 Deployment

Prerequisites

• Node.js Runtime (v20+)
• Active LAN connection (Wi-Fi or Ethernet)

1. Initialize Backend

cd server
npm install
node index.js

• The server will now display a friendly "Animal Name" (e.g., "Jolly Rabbit") and save its identity to .identity.json for persistence across restarts.
• If ports 3000 or 41235 are already in use, the server will now gracefully warn you instead of crashing.

2. Initialize Frontend

cd client
npm install
npm run dev -- --host

• The frontend is now accessible from other devices on your local network. Look for the "Network:" address in the console output (e.g., http://10.40.149.211:5173/).
• Each browser tab will generate its own unique "Animal Name" and will appear as a separate device in the Peer List.

3. Accessing the Dashboard

Open your web browser and navigate to http://localhost:5173/ (for local access) or http://YOUR_NETWORK_IP:5173/ (from other devices on your LAN).

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