Enervige - a statistical tool to break the Vigenère cypher

Cryptanalyse Vigenère is a Python-based project for encryption, decryption, and cryptanalysis of text using the Caesar and Vigenère ciphers. The project includes advanced statistical techniques to break the Vigenère cipher using methods like frequency analysis, mutual index of coincidence (ICM), and more.

This repository provides two ways to interact with the project:
1. Console Option: A command-line interface for advanced users and automation.
2. GUI Option: A graphical user interface for ease of use.
3. Standalone Executable GUI: A standalone executable application for Windows.

Features

Encryption & Decryption

• Caesar Cipher: Encrypts and decrypts text using a shift key.
• Vigenère Cipher: Encrypts and decrypts text using a keyword.

Cryptanalysis

• Cryptanalysis V1: Uses frequency analysis and statistical models to determine the probable key length and decrypt the text.
• Cryptanalysis V2: Leverages mutual index of coincidence (ICM) for improved accuracy in detecting patterns and key lengths.
• Advanced Statistics:
• Calculates frequency histograms and indices of coincidence.
• Detects repeating patterns and applies statistical heuristics for key recovery.
• Cryptanalysis V3:
• Maximizes Pearson's index of correlation between each column of the text and the target language's frequency table.

Installation and Setup

Prerequisites

Ensure you have Python 3.8 or higher installed on your system. Install required dependencies using pip:

pip install -r requirements.txt

Option 1: Running the Console Application

1. Clone the repository:
   bash git clone <repository-url> cd <repository-folder>

2. Run the script for console interaction:
   bash python cryptanalyse_vigenere.py --help

3. Command-line arguments:

4. Encrypt text:
   bash python cryptanalyse_vigenere.py --encrypt --text "TEXT" --key "KEY"
5. Decrypt text:
   bash python cryptanalyse_vigenere.py --decrypt --text "ENCRYPTED_TEXT" --key "KEY"
6. Cryptanalysis:
   bash python cryptanalyse_vigenere.py --analyse --text "CIPHER_TEXT"

Option 2: Running the GUI Application from Python

1. Install tkinter for Python if not already installed:
   bash sudo apt-get install python3-tk # For Ubuntu/Debian brew install python-tk # For macOS

2. Run the GUI:
   bash python enervige.py

3. Use the GUI to:

4. Encrypt text with a custom key.
5. Decrypt text with a provided key.
6. Perform cryptanalysis on encrypted text.

Option 3: (Windows) Running the Standalone enervige.exe

1. Same as Option 2 but with the default .exe on Windows systems
2. The binary is available at dist\enervige.exe

Usage Examples

Example 1: Console Encryption

python cryptanalyse_vigenere.py --encrypt --text "HELLO" --key "KEY"

Output:

Encrypted Text: XDFWN

Example 2: Cryptanalysis

python cryptanalyse_vigenere.py --analyse --text "XDFWN"

Output:

Decrypted Text: HELLO

Advanced Cryptanalysis Techniques

Statistical Tools

1. Frequency Analysis:
2. Creates histograms of letter frequencies to detect patterns.
3. Index of Coincidence (IC):
4. Identifies the probable length of the Vigenère key.
5. Mutual Index of Coincidence (ICM):
6. Compares frequency patterns of cipher columns for improved key length detection.

Unit Testing

1. To see the tests, open the tests subdirectory.
2. The files test-1-cesar.py, test-2-vigenere-cipher.py up to test-9-cryptanalyse-v3 are unit tests for each function and their combination.
3. These are tests for the cryptanalyse_vigenere.py which is the core functionality module around which the GUI enervige.py is wrapped around.
4. Feel free to add more unit tests when you contribute.

Limitations of enervige

• Short cipher texts may produce unreliable results due to insufficient statistical data.
• Assumes a standard frequency distribution for the French and English languages, which may not apply to non-standard texts.

License

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

Contributions

Contributions are welcome! Feel free to open issues or submit pull requests.

Updates

• Added support for cryptanalysis on English texts