SwiftCryptEngine 🔒🗜️

A lightweight, pure-Swift command-line engine implementing standard cryptographic ciphers and data compression algorithms from scratch.

This project was built to demonstrate core computer science principles—such as tree data structures, bitwise operations, dictionary-based compression, and polyalphabetic substitution—using clean Swift syntax and modern software testing practices.

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🚀 Features

1. Cryptography (Encryption/Decryption)

• Caesar Cipher: Simple substitution cipher shifting character Unicode scalar values. Supports large and negative shift boundaries.
• Vigenère Cipher: Polyalphabetic substitution cipher using a key phrase to shift letters dynamically.
• XOR Cipher: Bitwise symmetric encryption mapping data bytes against a secret key using the XOR (^) operator, outputted in standard Base64 format.

2. Compression (Lossless)

• Huffman Coding: A frequency-based frequency-sorted binary tree algorithm. It builds an optimal prefix tree (Huffman Tree) for the input text, generates variable-length bit codes, and compresses text into a binary stream.
• LZW (Lempel-Ziv-Welch): A dictionary-based compression algorithm that dynamically builds a translation table as it reads data, converting repeating patterns into integer codes.

3. CLI Interactive Sandbox

• A interactive terminal menu allowing you to input custom text strings and immediately see the compression/encryption ratios, key outputs, and verification checks.

4. Robust Unit Testing

• Built with Apple's modern Swift Testing framework, including edge cases (boundary checks, large shifts, negative shifts, binary-only check, and full string reconstruction).

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🛠️ Requirements & Installation

• macOS 14.0+ / Linux
• Swift 6.0+ / Xcode 15.0+

To clone and run this project locally:

# Clone the repository
git clone https://github.com/ChiefVenzox/SwiftCryptEngine.git

# Navigate into the project folder
cd SwiftCryptEngine

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💻 How to Run

Run the CLI Tool

Build and run the interactive suite directly from the command line:

swift run

Run Unit Tests

Verify correctness of the cryptographic and compression engines:

swift test

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📂 Project Structure

Sources/
  └── SwiftCryptEngine/
      ├── SwiftCryptEngine.swift   # CLI Entry Point & Interactive Menu
      ├── Ciphers.swift            # Caesar & Vigenère Implementations
      ├── XORCipher.swift          # Bitwise XOR Encryption
      ├── HuffmanCoding.swift      # Binary tree-based Huffman Compression
      └── LZW.swift                # Dictionary-based LZW Compression
Tests/
  └── SwiftCryptEngineTests/
      └── SwiftCryptEngineTests.swift # Modern Unit Tests using Swift Testing

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🤝 Contributing

Contributions, issues, and feature requests are welcome! Feel free to check the issues page.

📄 License

This project is licensed under the MIT License.