🕵️ StegApp: Secure Steganography Chat

StegApp is a privacy-focused Android messaging application that hides encrypted messages inside images using advanced Steganography techniques. Built with a modern tech stack, it ensures that your conversations look like innocent image exchanges to any third-party observer.

🚀 Key Features

• Pixels are the Password: Messages are embedded directly into the pixel data of images using Python-powered algorithms (running natively on Android via ChaquoPython).
• Invisible Encryption: Uses LSB (Least Significant Bit) and PVD (Pixel Value Differencing) techniques to ensure images look virtually identical to the original.
• Real-Time Global Chat: Powered by a Python FastAPI backend and Socket.IO for instant, low-latency messaging anywhere in the world.
• Cloud Synchronization:
  • MongoDB Atlas: Persists user accounts and chat metadata securely.
  • Cloudinary: Handles high-speed, lossless image storage to preserve steganographic data.
• Local-First Architecture:
  • Room Database: caches chats offline.
  • Jetpack Compose: provides a fluid, modern Material 3 UI.

🛠️ Tech Stack

Android (Client)

• Language: Kotlin
• UI Framework: Jetpack Compose (Material 3)
• Architecture: MVVM (Model-View-ViewModel) + Repository Pattern
• Storage: Room Database (SQLite), DataStore
• Networking: Retrofit, OkHttp, Socket.IO Client
• Python Integration: ChaquoPython (for Steganography algorithms)

Backend (Server)

• Framework: FastAPI (Python)
• Real-time: Python-SocketIO
• Database: MongoDB Atlas
• Storage: Cloudinary (Lossless optimization)
• Hosting: Render.com

🔧 Installation & Setup

1. Android App

1. Clone the repository.
2. Open in Android Studio Ladybug (or newer).
3. Sync Gradle dependencies.
4. Build & Run on an Emulator or Physical Device.

2. Backend Server (Optional - Self Hosting)

If you want to run your own backend instead of using the public one:

cd server
pip install -r requirements.txt
# Create .env file with CLOUDINARY and MONGODB keys
uvicorn main:app --reload

🔒 How it Works

1. Sender selects an image and types a secret message + password.
2. StegApp embeds the text into the image pixels locally.
3. The image is uploaded to Cloudinary (lossless) and delivered to the recipient.
4. Recipient taps the image and enters the password.
5. The hidden text is extracted and displayed!

🤝 Contributing

Pull requests are welcome! For major changes, please open an issue first to discuss what you would like to change.

📄 License

MIT