Distributed-Systems-Project: P2P-Chat

P2P-Chat is a decentralized messaging platform that allows users to communicate directly without relying on central servers. It ensures privacy, security, and efficient message delivery using a peer-to-peer (P2P) architecture. The system integrates local caching, SQLite databases for user-specific storage, and Docker-based networking to simulate real distributed environments.

By implementing a CHORD ring architecture, P2P-Chat enables efficient data lookup, replication to K successors, and fault tolerance. If a node fails, its data remains accessible through replicated backups. Multicast discovery allows dynamic identification of servers within the network.

Developed in Python and containerized using Docker, the platform uses RSA public-key cryptography and bcrypt for secure authentication and message encryption. The system is designed for both academic exploration and real-world distributed applications.

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Features

General

• Decentralized Messaging: Direct peer-to-peer messaging without central servers.
• CHORD Ring Architecture: Ensures data consistency, efficient lookups, and fault tolerance.
• Data Replication: Each server replicates data to K successors, maintaining availability.
• Message Persistence: Offline messages are cached and delivered when users reconnect.
• Multicast Discovery: Servers dynamically discover each other using multicast.
• Secure Authentication: User credentials are hashed with bcrypt, and RSA encryption secures communications.
• Fault Tolerance: Resilient messaging even during node or network failures.
• Docker Integration: Each client and server runs in isolated containers to mimic distributed networks.

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Client Functionalities

1. User Registration & Login

   • Register with a unique username and password.
   • Generates RSA key pairs for secure communication.
   • Supports single-session logins — logging in from a new client disconnects the old session and transfers messages.

2. Messaging

   • Direct messaging between users.
   • Cached messages for offline recipients.
   • Automatic delivery when recipients reconnect.
   • Local storage of chat history using SQLite.

3. Chat Management

   • View chat history, including delivered and pending messages.
   • Check recipient status before sending messages.
   • Seamless session transitions between devices.

4. Client GUI

   • Run the client interface with:

     docker exec -it client1 bash
     streamlit run app.py

   • A simple interface for managing chats, sending messages, and viewing history.

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Server Functionalities

1. User & Connection Management

   • Manages user registration, authentication, and status updates.
   • Tracks active users and their IPs across the network.
   • Uses multicast for dynamic discovery of new servers.

2. CHORD Ring & Data Replication

   • Implements CHORD ring architecture for efficient data distribution.
   • Replicates user data to K successors for fault tolerance.
   • Each server has two databases:
     • users: Stores user credentials and metadata.
     • backups: Contains replicated data from other nodes.

3. Heartbeat Monitoring

   • Regular health checks to track online status.
   • Automatically marks users as offline after inactivity.

4. Server GUI (CHORD Visualizer)

   • Visualize the CHORD ring using:

     python visualizer/app.py

   • It will prompt for a port. Use the port from the server’s Docker container (check docker-compose.yml).

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Security

• Password Security: Passwords are hashed using bcrypt.
• Message Encryption: RSA public-key encryption secures all messages.
• Data Integrity: Ensured through consistent replication and encrypted transfers.

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Setup Instructions

Prerequisites

• Docker
• Python 3.x
• Streamlit (for client GUI)

Running the Application

1. Clone the repository:

   git clone https://github.com/DanielMPMatCom/Distributed-Systems-Project.git
   cd Distributed-Systems-Project

2. Build and launch the Docker containers:

   Linux:

   chmod +x startup.sh
   ./startup.sh

   Windows:

   ./startup.bat

3. Start client or server GUIs as needed.

4. To change server IP:

   docker network disconnect distributed-systems-project_server_network server
   docker network connect --ip 192.168.1.3 distributed-systems-project_server_network server

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Additional Notes

• Logging in from a new client automatically transfers messages and disconnects the previous session.
• The CHORD ring visualizer helps monitor server connections and data distribution.
• Ensure all Docker containers are properly networked for seamless communication.