Steganography & Encryption Desktop Application

A desktop application that securely hides sensitive information within image files using advanced cryptography and steganography techniques.

🔐 Features

• Image Upload: Select any image file as a carrier for hidden data
• Message Encryption: Secure messages using 128-bit AES encryption with Galois/Counter Mode (GCM)
• LSB Steganography: Hide encrypted data in image pixels using Least Significant Bit (LSB) technique
• Password Protection: Use custom passwords to generate encryption keys
• File Safety: Automatically saves encoded images in PNG format
• Easy Retrieval: Decode hidden messages with the original password

🚀 How to Use

Encoding (Hiding a Message)

1. Launch the Application

   python3 stego_app.py

2. Upload an Image: Click the upload button to select your cover image

3. Enter Password: Type a secure password in the password field

4. Type Your Message: Enter the text message you want to hide

5. Click Encode: The application will:

   • Encrypt your message using 128-bit AES-GCM encryption with your password as the key
   • Hide the encrypted message in the image's pixels using LSB steganography
   • Save the result as a PNG file in your chosen location

Decoding (Retrieving a Message)

1. Launch the Application

   python3 stego_app.py

2. Upload Encoded Image: Select the image containing the hidden message

3. Enter Password: Type the same password used during encoding

4. Click Decode: The application will extract and decrypt your hidden message

🔧 Technical Details

Encryption

• Algorithm: AES-128 in Galois/Counter Mode (GCM)
• Key Derivation: Password-based key generation
• Security: Authenticated encryption with associated data (AEAD)
• Key Size: 128 bits (16 bytes)

Steganography

• Technique: Least Significant Bit (LSB) Embedding
• Method: The encrypted message is embedded into the least significant bit of each color channel (R, G, B) in image pixels
• Randomization: Embedding positions are randomized using a seed derived from the password, making the payload harder to detect
• Overhead: 32-bit header to store the message length for accurate extraction

File Format

• Input: Supports common image formats (JPEG, PNG, BMP, etc.)
• Output: Always saves as PNG to preserve data integrity and prevent lossy compression

📋 Requirements

See requirements.txt for all dependencies:

• Pillow: Image processing and manipulation
• tkinter: GUI framework (usually pre-installed with Python)

💻 Installation

1. Clone or download the project
2. Install dependencies:

   pip install -r requirements.txt

3. Run the application:

   python3 stego_app.py

⚠️ Security Notes

• Use strong, memorable passwords for encryption
• The security of your hidden data depends on your password strength
• LSB steganography is not visible to the naked eye but can be detected with steganalysis tools
• Always keep backups of important encoded images

📁 Project Structure

• stego_app.py: Main GUI application
• Stego.py: Core steganography functions (LSB embedding/extraction)
• aes_gcm.py: AES-128-GCM encryption implementation
• requirements.txt: Python dependencies

🎓 Educational Purpose

This project implements steganography and encryption for educational purposes, demonstrating cryptographic concepts and data hiding techniques.

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