Cipher Encryption Library

A robust, modern Java-based library implementing well-known classical ciphers with a focus on clean architecture and best practices.

🚀 Features

The library provides implementations for the following ciphers:

• Substitution Cipher: Monoalphabetic character replacement.
• Permutation Cipher: Block-based character transposition.
• Transposition Cipher: Columnar transposition.
• Affine Cipher: Mathematical substitution using modular arithmetic.
• Vigenere Cipher: Polyalphabetic substitution using a keyword.

📦 Getting Started

Prerequisites

• JDK 21 or higher
• Gradle (optional, gradlew wrapper included)

Building the Project

./gradlew build

Running the Demo

The library includes a demonstration in the Library class:

./gradlew run

Running Tests

./gradlew test

📖 Usage Example

import org.example.cipher.VigenereCipher;
import org.example.cipher.Cipher;

public class Example {
    public static void main(String[] args) {
        Cipher vigenere = new VigenereCipher("KEYWORD");
        String ciphertext = vigenere.encrypt("Hello World");
        String plaintext = vigenere.decrypt(ciphertext);
    }
}