Vig3n3r3 - A Python Vigenère Cipher Cracking Tool

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About Vig3n3r3

Vig3n3r3 is a Python-based cryptography tool designed to encrypt, decrypt, and crack Vigenère cipher-encrypted messages using various cryptanalysis methods like brute force, dictionary attacks, and crib attacks. This project is built as a tribute to one of history's most famous ciphers and demonstrates how modern techniques can unravel what was once thought to be unbreakable.

Table of Contents

• Features
• Setup
• Usage
• Screenshots
• Citing Data Sources
• Contributing
• License
• Link to Medium Article

Features

• Encrypt and Decrypt messages using the Vigenère cipher.
• Brute-force Attack: Crack a cipher by trying all possible keys.
• Dictionary Attack: Use a predefined wordlist to guess the key.
• Crib Attack: Use known plaintext segments to deduce the key.

Setup

To get started with Vig3n3r3, follow these steps:

1. Clone the repository

git clone https://github.com/your-username/vig3n3r3.git
cd vig3n3r3

2. Install dependencies

The project does not require any external Python packages. Just ensure you are using Python 3.x by checking:

python --version

3. Run the script

To run the script, use the following command:

python vig3n3r3.py "CIPHERTEXT" --method METHOD_NUMBER --keylength LENGTH --crib "KNOWN_PLAINTEXT"

• CIPHERTEXT: The encrypted message.
• METHOD_NUMBER: Choose from 1 (dictionary), 2 (brute force), 3 (crib attack), etc.
• LENGTH: The length of the key (required for methods 1 and 2).
• KNOWN_PLAINTEXT: The known part of the plaintext (required for method 3).

Usage

Example 1: Brute-force attack

python vig3n3r3.py "KXRKGIKXBKAL" --method 2 --keylength 3

This will attempt to brute force the key of length 3 and decrypt the message.

Example 2: Dictionary attack

python vig3n3r3.py "KXRKGIKXBKAL" --method 1 --keylength 3

This will search for a valid key of length 3 using the words from words.txt.

Example 3: Crib attack

python vig3n3r3.py "KXRKGIKXBKAL" --method 3 --crib "ATTACK"

This will attempt to find the key by using "ATTACK" as known plaintext.

Citing Data Sources

• The wordlist for the dictionary attack was sourced from the enable1.txt wordlist, a popular open-source wordlist.
• The monograms, bigrams, trigrams, and quadgrams data used for frequency analysis were obtained from Peter Norvig's Ngram Data.

Contributing

Welcoming contributions! Please feel free to submit a pull request or open an issue if you'd like to improve or fix something.

Instructions for contributing:

1. Fork the repository.
2. Create your feature branch (git checkout -b feature/AmazingFeature).
3. Commit your changes (git commit -m 'Add some AmazingFeature').
4. Push to the branch (git push origin feature/AmazingFeature).
5. Open a pull request.

License

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

Link to Medium Article

For a detailed breakdown of the history behind the Vigenère cipher, modern cryptography techniques, and the story of Vig3n3r3, read my article on Medium: The Vigenère Cipher: From Unbreakable Enigma to Cryptographic Relic.

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