🔐 Secure Password Vault (Java, AES Encryption)

This is a simple Java-based Secure Password Vault that allows users to securely store and retrieve passwords using AES encryption. It's designed for learning and personal use.

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📌 Features

• 🔑 Master password-based AES-128 encryption
• 💾 Save multiple website credentials (website, username, password)
• 🔓 Decrypt credentials with the correct master password
• ✅ Input validation and file-based storage
• 🔒 Encryption key is always 128-bit padded or derived securely

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📁 File Structure

SecurePasswordVault/
├── SecurePasswordVault.java     # Main program
├── credentials.enc              # Encrypted credentials (created at runtime)
└── README.md                    # You're reading this!

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⚙️ How It Works

1. User enters a master password
2. The password is converted into a 16-byte AES encryption key
3. Data is encrypted and saved to a file
4. To read data, the correct master password must be entered again

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🔧 Setup Instructions

✅ Requirements

• Java Development Kit (JDK) 8 or later
• Text editor or IDE (e.g., IntelliJ, Eclipse, VSCode)

🚀 Compile & Run

javac SecurePasswordVault.java
java SecurePasswordVault

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🧠 How Encryption Works

This app uses AES in ECB mode (for simplicity in this example).

🔐 Key Generation

To fix potential errors like:

Exception in thread "main" java.lang.IllegalArgumentException: Invalid offset/length combination

We ensure the key is always 16 bytes with this logic:

byte[] keyBytes = new byte[16];
byte[] passwordBytes = masterPassword.getBytes();
for (int i = 0; i < Math.min(passwordBytes.length, 16); i++) {
    keyBytes[i] = passwordBytes[i];
}
SecretKey secretKey = new SecretKeySpec(keyBytes, "AES");

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🧪 Sample Input/Output

Welcome to Secure Password Vault
Enter master password: *****

1. Save credentials
2. View credentials
3. Exit
Choice: 1

Enter website: example.com
Enter username: testuser
Enter password: mySecurePass123
Credentials saved successfully.

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🚫 Limitations

• No password strength checks
• No UI (CLI-based only)
• Uses ECB mode (not suitable for production — use CBC or GCM in real apps)

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✅ To-Do & Improvements

• GUI with Swing or JavaFX
• Store data using a database (SQLite)
• Master password hashing (SHA-256 + PBKDF2)
• Add password strength meter
• Use AES/CBC or AES/GCM with IV

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⚠ Disclaimer

🛡️ This tool is intended for educational purposes only. Do not use this in production or to store real sensitive data.

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👨‍💻 Author

Divyanshu Java & Cybersecurity Enthusiast

Happy coding!