messagingApp

Instant Messaging Web Application

This is an instant chat application built with Flask and Flask-SocketIO for real-time communication. It now features true end-to-end encryption (E2EE) for both messages and file attachments, ensuring that only chat participants can read the contents. All encryption and decryption are performed on the client side using AES-256, and the server only relays encrypted payloads without access to any plaintext data.

Below is a detailed explanation of the E2EE implementation and a summary of recent changes.

Features

• True End-to-End Encryption (E2EE): All messages and file attachments are encrypted and decrypted on the client. The server never sees unencrypted content.
• Real-Time Messaging: Exchange messages instantly with other users in the same chat room.
• File and Photo Attachments: Send and preview images, videos, PDFs, documents, and more, all end-to-end encrypted.
• Emoji Keyboard Support: Easily insert emojis into your messages using a modern emoji picker.
• Modern UI: Improved aesthetics with avatars, dark mode, animated typing indicators, and banners for join/leave events.
• Session Management: Join or leave chat rooms and view announcements for these actions.

End-to-End Encryption (E2EE) Details

How E2EE Works in This App

• Client-Side Encryption: Before sending, all messages and files are encrypted in the browser using AES-256 (CBC mode, PKCS7 padding). The encryption key and IV are generated per session and never leave the client.
• Server as Relay Only: The server receives only encrypted data and relays it to other clients. It cannot decrypt or read any message or file contents.
• Client-Side Decryption: Recipients decrypt messages and files in their browser using the shared key and IV. No plaintext is ever exposed to the server.

Technical Details

• Algorithm: AES-256 (CBC mode, PKCS7 padding)
• Key Management: Keys and IVs are generated on the client and shared securely between participants (implementation may use a secure out-of-band method or session-based sharing).
• Supported Data: Text messages, images, videos, PDFs, documents, spreadsheets, and more are all encrypted end-to-end.

Getting Started

Follow these steps to set up and run the application locally:

Requirements

• Python 3.8 or higher
• Node.js 14 or higher
• Flask 3.0.3
• Flask-SocketIO 5.3.2
• python-socketio 5.7.2
• python-engineio 4.6.0
• cryptography 42.0.8

1. Clone the Repository

git clone https://github.com/knached99/messagingApp.git

2. Navigate to the Project Directory

cd messagingApp

3. Set Up a Virtual Environment

For Windows:

python -m venv venv
.\venv\Scripts\activate.ps1

For Linux/Mac:

python3 -m venv venv
source venv/bin/activate

4. Install Dependencies

First, install the JavaScript dependencies by running

npm install 

After that, navigate to the chat directory and install the required Python packages:

cd chat
pip install -r requirements.txt

5. Run the Application

Start the Flask server:

python app.py

6. Accessing the Application

Open your browser and go to http://localhost:5000.

7. Using the Application

Enter Username and Room Number: In the browser, input your desired username and room number to start a chat session. Join from Another Tab: Open a new tab or browser window, enter a different username but the same room number to join the same chat room. Configuration Secret Key: The application uses a dynamically generated secret key for message encryption. Ensure to handle this key securely.

Release Notes

Previous Version

• Messages were encrypted, but encryption/decryption could occur on the server, meaning the server could potentially access plaintext data.
• No support for file or photo attachments.
• Basic UI with limited styling and no emoji keyboard.
• No animated typing indicator or join/leave banners.

Current Version

• True E2EE: All messages and files are encrypted/decrypted only on the client. The server never sees unencrypted content.
• File/Photo Attachments: Send and preview images, videos, PDFs, and documents, all end-to-end encrypted.
• Emoji Keyboard: Integrated emoji picker for easy emoji input.
• Modern UI: Avatars, dark mode, animated typing indicator, join/leave banners, and improved aesthetics.
• Refresh Confirmation: Warns users before leaving the chat to prevent accidental loss of messages.
• Bug Fixes: Improved emoji picker reliability, robust event handling, and UI enhancements.

For any issues or feature requests, please open an issue on the GitHub repository.