Ultimate Cipher Application

A comprehensive encryption/decryption tool that combines multiple cipher algorithms for enhanced security:

• Affine Cipher
• Vigenere Cipher
• Transposition Cipher
• XOR-based Stream Cipher

Features

• Dual Interface:
  • Interactive Terminal Menu
  • Modern Web Interface
• Input Validation:
  • Real-time validation for all inputs
  • Clear error messages
  • Helpful guidance for valid values
• Multiple Cipher Layers:
  • Affine Cipher with coprime key validation
  • Vigenere Cipher with alphabetic key
  • Transposition Cipher using Vigenere key length
  • XOR-based Stream Cipher for additional security

Prerequisites

• Python 3.7 or higher
• pip (Python package installer)
• Terminal/Command Prompt
• Web browser (for web interface)

Installation

1. Clone or download this repository:

git clone <repository-url>
cd ultimate-cipher

2. Create a virtual environment:

For Windows:

# Create virtual environment
python -m venv venv

# Activate virtual environment
.\venv\Scripts\activate

# If you encounter execution policy error, run PowerShell as Administrator and execute:
Set-ExecutionPolicy RemoteSigned

For macOS/Linux:

# Create virtual environment
python3 -m venv venv

# Activate virtual environment
source venv/bin/activate

3. Install required packages:

pip install -r requirements.txt

Usage

Terminal Interface

1. Activate the virtual environment (if not already activated):

   • Windows: .\venv\Scripts\activate
   • macOS/Linux: source venv/bin/activate

2. Run the terminal interface:

python menu_cli.py

3. Follow the interactive menu:
   • Choose operation (Encrypt/Decrypt)
   • Enter text to process
   • Provide encryption/decryption keys:
     • Affine key 'a' (must be coprime with 26)
     • Affine key 'b' (0-25)
     • Vigenere key (alphabetic characters only)
     • XOR key (any text)

Web Interface

1. Activate the virtual environment (if not already activated)

2. Run the Flask application:

python app.py

3. Open your web browser and navigate to:

http://localhost:5000

4. Use the web form to:
   • Enter text to process
   • Select operation (Encrypt/Decrypt)
   • Provide required keys
   • View results with original and processed text

Valid Key Values

Affine Cipher

• Key 'a': Must be coprime with 26
  • Valid values: 1, 3, 5, 7, 9, 11, 15, 17, 19, 21, 23, 25
• Key 'b': Any number between 0 and 25

Vigenere Cipher

• Key must contain only alphabetic characters (A-Z, a-z)
• Case insensitive
• No spaces or special characters allowed

XOR Cipher

• Any text can be used as key
• Longer keys provide better encryption

Example Usage

Terminal Interface Example:

# Start the terminal interface
python menu_cli.py

# Example inputs:
Text: Hello World
Affine key 'a': 5
Affine key 'b': 8
Vigenere key: SECRET
XOR key: MyXORKey

Web Interface Example:

1. Start the web server:

python app.py

2. Fill in the web form with the same example values as above
3. Click "Process" to see the results

Security Considerations

• This is a demonstration tool and should not be used for sensitive data
• The web interface uses a default secret key - change it in production
• Keys should be kept secure and not shared
• Longer keys generally provide better security

Troubleshooting

1. If you see "Permission denied" when activating venv:

   • Run PowerShell as Administrator
   • Execute: Set-ExecutionPolicy RemoteSigned

2. If Flask shows "No module named 'flask'":

   • Ensure virtual environment is activated
   • Run: pip install -r requirements.txt

3. If web interface shows CSRF error:

   • Clear browser cache
   • Restart Flask application

License

MIT License - Feel free to use and modify as needed.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.