Secure Multi-Room Chat System (Socket Programming Project)

Overview

This project implements a secure, scalable multi-client chat system using low-level socket programming in Python. It supports multiple chat rooms, private messaging, file transfer, and encryption, while ensuring secure communication using SSL/TLS.

The system demonstrates core networking concepts including:

• TCP socket programming
• Multi-threaded client handling
• Custom application-layer protocol
• Secure communication using SSL/TLS
• Performance monitoring and error handling

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Features

Chat Functionality

• Multi-client support
• Multi-room chat system
• Real-time message broadcasting
• Private messaging between users

Security

• SSL/TLS encryption for all communication
• Additional application-layer encryption using Fernet (for secret messages)
• Protection against plaintext packet sniffing

File Transfer

• Send and receive files within a chat room
• Chunk-based file transmission

Performance & Reliability

• Concurrent client handling using threads
• Message framing using custom JSON protocol
• Graceful handling of client disconnects
• Periodic performance monitoring (messages, clients, files)

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Architecture

The system follows a client-server architecture:

• Server

  • Handles multiple clients concurrently
  • Manages chat rooms
  • Broadcasts messages
  • Handles file transfers

• Client

  • Connects securely using TLS
  • Sends/receives messages
  • Supports commands for private/secret/file messages

• Protocol Layer

  • Custom JSON-based communication protocol
  • Ensures proper message framing over TCP

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Communication Flow

1. Client connects to server using TLS
2. User joins a room
3. Messages are sent as JSON packets
4. Server broadcasts messages to room members
5. File data is streamed after metadata exchange

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Technologies Used

• Python (Socket Programming)
• SSL/TLS (secure communication)
• threading (concurrency)
• cryptography (Fernet encryption)
• JSON (custom protocol)

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⚙️ Setup Instructions

1️ Clone the Repository

git clone https://github.com/Manoj-kanur/encrypted-chat-system-python.git
cd encrypted-chat-system-python

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2️ Install Dependencies

pip install -r requirements.txt

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3️ Generate SSL Certificates (IMPORTANT)

openssl req -new -x509 -days 365 -nodes -out cert.pem -keyout key.pem

⚠️ Note: SSL keys are not included in the repository for security reasons.

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4️ Run the Server

python server.py

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5️ Run the Client

python client.py

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💻 Client Commands

Command	Description
Normal text	Send message to room
/private user msg	Send private message
/secret user msg	Send encrypted message
/file path	Send file
/exit	Disconnect

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🔍 Wireshark Analysis (Security Validation)

• Captured packets show TLS handshake

• All chat messages appear as:

  • TLS Application Data (Encrypted)

• No plaintext data is visible

✔ Confirms secure communication

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📊 Performance Evaluation

The system was tested with multiple clients and showed:

• Stable concurrent connections
• No message loss under load
• Efficient message broadcasting
• Periodic server statistics logging

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📁 Project Structure

project/
│
├── server.py
├── client.py
├── protocol.py
├── encryption_utils.py
│
├── README.md
├── requirements.txt
├── .gitignore

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🎯 Key Learning Outcomes

• Understanding of TCP socket programming
• Designing custom communication protocols
• Implementing SSL/TLS security
• Handling concurrency and synchronization
• Debugging real-world network issues

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👨‍💻 Authors

K R Manoj

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📜 License

This project is part of academic purposes.