🔐 CryptiHub | Secure Encrypted Chat System

A real-time room-based chat system with end-to-end encryption designed to secure communication using modern cryptographic standards.

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📌 Overview

CryptiHub is a lightweight encrypted chat system built for secure communication over networks.

It supports:

• Room-based secure messaging
• Real-time multi-client communication
• Strong symmetric encryption pipeline

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✨ Features

• 🔒 End-to-End Encryption (Fernet / AES-256)
• 🧵 Multi-client real-time chat via sockets
• 🛡️ Room-based authentication system
• 🔑 PBKDF2 key derivation (1.2M iterations)
• ⚡ Thread-safe server architecture

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⚙️ Installation

📥 Clone Repository

git clone https://github.com/pevinkumar10/CryptiHub.git
cd CryptiHub

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📦 Install Dependencies

Windows:

pip install -r requirements.txt

Linux:

sudo apt-get install python3-tk

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⚙️ Configuration

🖥️ Server Config

Edit:

server/modules/core.py

HOST = ""
PORT = 1234

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💻 Client Config

Edit:

client/client.py

HOST = ""
PORT = 1234

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🚀 Usage

▶️ Start Server

python3 server/server.py

💬 Start Client

python3 client/client.py

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🔐 Security Architecture

1. Key Derivation

• PBKDF2-HMAC-SHA256
• 1,200,000 iterations
• Per-message random salt (16 bytes)
• 32-byte derived encryption key

2. Encryption Layer

• Fernet (AES-256)
• Message-level encryption
• Replay attack resistance via salts

3. Authentication Model

• Room-based access control
• Username collision prevention
• Shared session key per room

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⚠️ Limitations

This implementation uses shared symmetric keys, meaning:

• Server can potentially decrypt messages
• Not fully true E2EE

Recommended Improvements:

• Diffie-Hellman key exchange
• Ephemeral session keys
• Client-side key storage only

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📜 License

MIT License © 2025 PevinKumar A