AES Chat 🔐

A secure, encrypted chat application that enables private communication between two parties using military-grade AES encryption.

📋 Overview

This project implements a secure chat application where two users can exchange encrypted messages over a network. All communications are protected using AES-256 encryption with message integrity verification, ensuring conversations remain private and tamper-proof even over untrusted networks.

✨ Features

• 🔒 AES-256 Encryption: Military-grade encryption protects all message content
• 🛡️ Message Integrity: SHA-256 hashes verify messages haven't been tampered with
• ⚡ Real-time Communication: Bidirectional messaging with simultaneous send/receive
• 🕐 Timestamped Messages: Each message includes transmission timestamp
• ✅ Integrity Verification: Visual indicators (☑/☒) show message authenticity
• 🔑 Pre-shared Key Security: Both parties must know the same encryption key

Preview

When correct key is entered

When incorrect key is entered

🚀 How It Works

1. Server Setup: One person runs the server and waits for connections
2. Client Connection: Another person connects using the server's IP and port
3. Key Exchange: Both parties enter the same pre-shared encryption key
4. Secure Chat: Messages are automatically encrypted before sending and decrypted upon receipt
5. Verification: Each message's integrity is verified using SHA-256 hashes

📦 Requirements

• Python 3.x
• pyaes module for pure Python AES implementation

# Windows
python -m pip install pyaes

# Linux/macOS
pip install pyaes

Note: We chose pyaes for its simple, pure Python implementation. Other options like pycrypto (vulnerable and unmaintained) or pycryptodome/pycryptodomex are available, but we prioritized simplicity and security.

🛠️ Installation & Usage

1. Clone the Repository

git clone https://github.com/centauri1219/AES-chat.git
cd AES-chat

2. Install Dependencies

pip install pyaes

3. Start the Server

python server.py [optional_port]

• Default port: 5555
• Server will wait for client connection

4. Connect with Client

python client.py

• Enter server IP address
• Enter server port
• Enter the same encryption key as the server

5. Start Chatting!

• Type messages and press Enter to send
• Type quit() to exit the chat

🔧 Technical Details

• Encryption: AES block cipher with 16-byte blocks
• Key Derivation: SHA-256 hash of user-provided key
• Message Format: JSON with timestamp, message, and integrity hash
• Padding: Uses ~ characters to pad messages to 16-byte boundaries
• Threading: Multi-threaded for simultaneous send/receive operations

🔒 Security Features

• Confidentiality: AES-256 encryption protects message content
• Integrity: SHA-256 hashes detect message tampering
• Authentication: Pre-shared key ensures only authorized parties can communicate

⚠️ Important Notes

• Server must be started before client attempts connection
• Both parties must use the exact same encryption key
• This is for educational/demonstration purposes
• Consider additional security measures for production use

📄 License

This project is open source. Feel free to use and modify as needed.