🔐 Caesar Cipher Web Application

A simple and elegant web-based Caesar cipher encryption/decryption tool built with Python Flask. This application allows users to encrypt and decrypt messages using the classic Caesar cipher algorithm through an intuitive web interface.

🌟 Features

• Encryption & Decryption: Easily encrypt or decrypt text messages
• Web Interface: Clean, responsive design with gradient styling
• Real-time Processing: Instant results without page refresh
• Case Preservation: Maintains uppercase and lowercase letters
• Non-alphabetic Support: Preserves numbers, spaces, and special characters
• User-friendly: Simple 0-25 shift range with clear instructions

🚀 Quick Start

Prerequisites

• Python 3.7 or higher
• pip (Python package installer)

Installation

1. Clone the repository:

   git clone https://github.com/yourusername/caesar-cipher.git
   cd caesar-cipher

2. Create a virtual environment (recommended):

   python -m venv venv
   # On Windows
   venv\Scripts\activate
   # On macOS/Linux
   source venv/bin/activate

3. Install dependencies:

   pip install -r requirements.txt

4. Run the application:

   python app.py

5. Open your browser and navigate to:

   http://localhost:5000
   

📖 Usage

1. Enter your message in the text area
2. Set the shift value (0-25)
3. Click "Encrypt" to encode your message
4. Click "Decrypt" to decode a message
5. View results in the output box below

Example:

• Original: "Hello World"
• Shift: 3
• Encrypted: "Khoor Zruog"
• Decrypted: "Hello World"

🛠️ Technical Details

Project Structure

caesar-cipher/
├── app.py                 # Flask web application
├── caesar.py             # Caesar cipher algorithm
├── requirements.txt      # Python dependencies
├── README.md            # This file
├── LICENSE              # MIT License
├── .gitignore           # Git ignore rules
└── templates/
    └── index.html       # Web interface

API Endpoints

• GET / - Serve the main web interface
• POST /process - Process encryption/decryption requests
  • Request Body: {"message": "text", "shift": number, "mode": "encrypt|decrypt"}
  • Response: {"result": "processed_text"}

Algorithm

The Caesar cipher shifts each letter in the alphabet by a fixed number of positions:

• Encryption: (character_position + shift) % 26
• Decryption: (character_position - shift) % 26
• Non-alphabetic characters remain unchanged
• Case is preserved (uppercase/lowercase)

🤝 Contributing

Contributions are welcome! Feel free to:

• Report bugs
• Suggest new features
• Improve documentation
• Submit pull requests

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

• Inspired by classical cryptography techniques
• Built with Flask web framework
• Designed for educational purposes

📞 Support

If you encounter any issues or have questions, please open an issue on GitHub.