HexGuard - AES Encryption Library

Overview

HexGuard is an AES encryption library implemented in C. This project is part of my 13th grade final project for the academic year 2024-2025. The goal is to implement a robust AES encryption system while exploring advanced cryptographic techniques.

Features

• AES Encryption & Decryption

  • Supports AES-128, AES-192, and AES-256 key sizes.
  • Implements ECB, CBC, and CFB modes of operation.
  • Uses PKCS#7 padding.

• Key & IV Handling

  • Random key generation and IV creation.
  • (Used an external lib didn't impliment my self the generation)

• Text & File Support

  • Encrypts/decrypts text and files (binary-safe).

• DLL & EXE Build Modes

  • Build as a Windows DLL or a testable executable.

• Python Frontend

  • Simple encryption GUI using HTML, CSS, JS.
  • Powered by FastApi

• Testing Framework

  • Includes unit tests for encryption and decryption.
  • Validates correct key expansion and AES transformations.

Technologies Used

• C – Core AES encryption implementation.
• Python – Used for backend API and DLL interaction with FastAPI.
• HTML / CSS / JavaScript – Simple web interface for user interaction.
• CMake – Build system used to compile the AES code into a DLL or EXE.
• FastAPI – Framework powering the Python backend.
• ctypes – Used for calling C functions from Python.

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Installation & Setup

1. Clone the Repository

git clone https://github.com/Itapit/hexguard.git
cd hexguard

2. Set Up Python Environment (Frontend)

cd backend
python -m venv venv
venv\Scripts\activate  # On Windows
pip install fastapi uvicorn python-multipart

Then run:

uvicorn backend.main:app --reload

This serves the frontend at http://127.0.0.1:8000.

3. Build C Components Using CMake

Option A: Build DLL (for integration)

cmake -S . -B build -DBUILD_DLL=ON
cmake --build build

Output: build/bin/Debug/aes.dll

Option B: Build and Run Tests

cmake -S . -B build -DBUILD_DLL=OFF
cmake --build build
./build/bin/Debug/test_aes.exe

Output: build/bin/Debug/test_aes.exe

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File Structure

hexguard/
├── backend/
│   ├── api.py              # FastAPI routes
│   ├── dll_wrapper.py      # Interface to AES DLL
│   └── main.py             # FastAPI app runner
│
├── build/
│   └── bin/
│       └── Debug/
│           ├── aes.dll        # DLL output
│           └── test_aes.exe   # Executable with the unit testing
│
├── frontend/
│   ├── index.html          # UI layout
│   ├── script.js           # Frontend logic
│   └── style.css           # UI styling
│
├── include/
│   └── aes.h               # AES header file
│
├── lib/
│   └── aes.c               # AES C implementation
│
├── tests/
│   └── test_aes.c          # Unit tests
│
├── CMakeLists.txt
│
└── README.md

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Roadmap & Future Work

• Implement additional AES modes of operation (e.g., OFB, CTR).
• Optimize key expansion for better efficiency.
• Improve error handling for encryption functions.
• Using graph theory to add additional cryptographic enhancements to the key expansion.
• Adding a GUI that will be written in Java, utilizing the C code as a DLL.

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Contact

For questions or contributions, reach out at [email protected].