Secure Message Exchange

This repository is a small project designed to familiarize myself with the basics of secure message exchange. It demonstrates core concepts like message encryption, decryption, and secure transmission using Rust. Disclaimer: This implementation is far from perfect and should not be considered a role model for any production environment. It is intended solely for educational purposes.

Features

• Message Transmission: Send and receive messages over a TCP connection.
• Message Encryption: Encrypt messages using RSA public/private key pairs.
• Message Decryption: Decrypt received messages securely.
• Metadata Handling: Includes message size headers for proper parsing.

Dependencies

This project uses the following external crates:

• clap: For parsing command-line arguments.
• rsa: For RSA encryption and decryption.
• tokio: For asynchronous networking.

Code Structure

• cryptography: Contains helper functions for RSA encryption and decryption.
• msg_handler: Manages sending and receiving messages, including handling size headers and interfacing with the cryptography module.
• main.rs: The entry point of the application.

How It Works

1. Setup:

   • A public/private RSA key pair is used for encrypting and decrypting messages.
   • The TcpListener and TcpStream from the tokio crate handle networking.

2. Sending a Message:

   • The message is encrypted using the recipient's public key.
   • A size header is prepended to the encrypted message.
   • The complete message is transmitted over the network.

3. Receiving a Message:

   • The size header is read first to allocate the correct buffer.
   • The encrypted message is read and then decrypted using the private key.