Here’s a clean, professional GitHub README.md you can directly paste into your repo (edit-friendly, well-structured, and impressive 👇)

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🔐 Steganographic Chat App (AES + Image Hiding)

A secure communication system that combines AES encryption with image steganography to hide secret messages inside images.

This project ensures:

• 🔒 Confidentiality (AES encryption)
• 🕵️ Stealth (hidden inside images)
• ✅ Integrity (SHA-256 checksum verification)

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🚀 Features

• AES-128 encryption (CBC mode)
• Secure random key generation
• Message embedding inside images (LSB technique)
• Data integrity check using SHA-256
• Sender & Receiver simulation
• Simple CLI-based interface

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🧠 How It Works

🔹 Sender Side

1. User enters a message

2. Message is encrypted using AES

3. Checksum is generated

4. Encrypted message is hidden inside an image

5. Sender shares:

   • Encoded image
   • Encryption key
   • Checksum

🔹 Receiver Side

1. Extract hidden data from image
2. Verify checksum
3. Decrypt message using AES key
4. Display original message

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📂 Project Structure

📁 steganographic-chat-app
│── main.py              # Main application
│── README.md           # Documentation
│── sample_images/      # Input/output images (optional)

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⚙️ Installation

1. Clone the repository

git clone https://github.com/your-username/steganographic-chat-app.git
cd steganographic-chat-app

2. Install dependencies

pip install pycryptodome pillow

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▶️ Usage

Run the program:

python main.py

Choose mode:

📤 Send a Message

• Enter your secret message
• Provide input image path
• Output encoded image will be generated

📥 Receive a Message

• Provide encoded image path
• Enter key & checksum
• Message will be decrypted

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🔑 Security Details

AES Encryption

• Mode: CBC (Cipher Block Chaining)
• Key Size: 128-bit
• Random IV used for each encryption

Steganography

• Uses LSB (Least Significant Bit) technique
• Stores data in RGB pixel values

Integrity Check

• SHA-256 checksum ensures data is not altered

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⚠️ Limitations

• Image must be large enough to store message
• Key sharing must be done securely
• Not resistant to advanced steganalysis

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💡 Future Improvements

• GUI (Tkinter / React frontend)
• Support for audio/video steganography
• Public-key encryption (RSA)
• Secure key exchange (Diffie-Hellman)
• Compression before encoding
• Multi-user chat system

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🧪 Example

Message: Hello World
Encrypted → Hidden in image → Sent

Receiver:
Extract → Verify → Decrypt → Output: Hello World

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🤝 Contributing

Pull requests are welcome! For major changes, please open an issue first.

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📜 License

This project is licensed under the MIT License.

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👩‍💻 Author

PoojaCodesX

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⭐ Support

If you like this project:

• ⭐ Star the repo
• 🍴 Fork it
• 📢 Share it