🔐 Java AES Encryption Engine

A lightweight Java implementation of the Advanced Encryption Standard (AES) algorithm for encrypting and decrypting data. This project demonstrates symmetric-key cryptography using Java's built-in javax.crypto library.

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📌 Table of Contents

• About the Project
• Features
• Project Structure
• Prerequisites
• Getting Started
  • Clone the Repository
  • Running with Eclipse
  • Running from Command Line
• How It Works
• AES Overview
• Technologies Used
• Contributing
• License

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About the Project

The Java AES Encryption Engine provides a clean and straightforward implementation of AES encryption and decryption in Java. It is ideal for learning cryptographic concepts, prototyping secure data handling, or integrating encryption into Java-based applications.

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✨ Features

• AES-based symmetric encryption and decryption
• Encodes encrypted output in Base64 for safe text representation
• Uses Java's standard javax.crypto and java.security libraries (no external dependencies)
• Modular package structure with clear separation of concerns (main, key_management, cryptography_engine, file_io)
• Eclipse-compatible project setup (.classpath and .project included)

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📁 Project Structure

Java-AES-Encryption-Engine/
├── src/com/aes
│   ├── main/
│   │   └── ApplicationMain.java        # The Orchestrator — entry point, ties all modules together
│   │
│   ├── key_management/
│   │   └── KeyGeneratorUtil.java       # The Vault — handles AES key generation and management
│   │
│   ├── cryptography_engine/
│   │   └── AESGCMCipher.java           # The Grinder — performs AES-GCM encryption & decryption
│   │
│   └── file_io/
│       └── SecureFileStreamer.java     # The Pipeline — manages secure file reading and writing
│
├── .classpath                          # Eclipse classpath configuration
├── .project                            # Eclipse project configuration
└── README.md

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✅ Prerequisites

• Java JDK 8 or higher — Download here
• Eclipse IDE (optional, for IDE-based setup) — Download here

Verify your Java installation:

java -version
javac -version

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🚀 Getting Started

Clone the Repository

git clone https://github.com/harshraj005/Java-AES-Encryption-Engine.git
cd Java-AES-Encryption-Engine

Running with Eclipse

1. Open Eclipse IDE.
2. Go to File → Import → Existing Projects into Workspace.
3. Browse to the cloned project folder and click Finish.
4. Right-click ApplicationMain.java inside src/main/ and select Run As → Java Application.

Running from Command Line

# Navigate to the src directory
cd src

# Compile all Java files across all packages
javac main/ApplicationMain.java key_management/KeyGeneratorUtil.java cryptography_engine/AESGCMCipher.java file_io/SecureFileStreamer.java

# Run the application
java main.ApplicationMain

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⚙️ How It Works

The engine is split into four focused modules, each with a single responsibility:

Module	Class	Role
main	ApplicationMain.java	The Orchestrator — entry point that wires all modules together and drives the flow
key_management	KeyGeneratorUtil.java	The Vault — generates and manages the AES secret key securely
cryptography_engine	AESGCMCipher.java	The Grinder — performs AES-GCM authenticated encryption and decryption
file_io	SecureFileStreamer.java	The Pipeline — handles reading plaintext input and writing encrypted output to files

Encryption flow:

Input File  →  [SecureFileStreamer]  →  [KeyGeneratorUtil]  →  [AESGCMCipher]  →  Encrypted Output File

Decryption flow:

Encrypted File  →  [SecureFileStreamer]  →  [AESGCMCipher]  →  [KeyGeneratorUtil]  →  Decrypted Output File

AES-GCM (Galois/Counter Mode) provides both confidentiality (encryption) and integrity (authentication tag), making it more secure than plain AES-ECB or AES-CBC modes.

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🔑 AES Overview

AES (Advanced Encryption Standard) is a symmetric block cipher adopted by the U.S. National Institute of Standards and Technology (NIST). Key characteristics:

Property	Details
Type	Symmetric block cipher
Key sizes	128, 192, or 256 bits
Block size	128 bits
Standard	FIPS PUB 197
Common modes	ECB, CBC, GCM ✅ (used here)

AES operates through multiple rounds of substitution, permutation, and mixing steps to produce ciphertext that is computationally infeasible to reverse without the correct key.

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🛠️ Technologies Used

• Java — Core language
• javax.crypto — Cipher, SecretKeySpec
• java.security — Key management
• java.util.Base64 — Encoding/decoding encrypted output
• Eclipse IDE — Development environment

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🤝 Contributing

Contributions are welcome! To contribute:

1. Fork the repository
2. Create a new branch: git checkout -b feature/your-feature-name
3. Make your changes and commit: git commit -m "Add your message"
4. Push to the branch: git push origin feature/your-feature-name
5. Open a Pull Request

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📄 License

This project is open source. Feel free to use, modify, and distribute it for educational or personal use.

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Author: harshraj005
Repository: Java-AES-Encryption-Engine