🔐 Secure Files (C# WinForms)
A simple Windows Forms application that lets you encrypt and decrypt files with a password. Built with AES-GCM (256-bit) for strong encryption and PBKDF2 (HMAC-SHA256) for key derivation.
✨ Features
🔑 Password-based encryption (PBKDF2 with 200,000 iterations).
🔒 AES-256 GCM mode for secure encryption + authentication tag.
📝 Custom file header format storing:
Magic bytes (PWDF)
Version
Salt (16 bytes)
Nonce (12 bytes)
Tag (16 bytes)
Ciphertext
📂 Automatically saves encrypted/decrypted files to your Documents folder.
🖥️ Clean WinForms UI with two buttons: Encrypt File and Decrypt File.
🖥️ How It Works
Encrypt File
User selects a file path and enters a password.
A 16-byte salt and 12-byte nonce are generated.
PBKDF2 derives a 256-bit key from the password + salt.
File contents are encrypted with AES-GCM.
Output file: filename.ext.pwdf in the user’s Documents folder.
Decrypt File
Reads the header from the .pwdf file.
Re-derives the same key from the stored salt, iterations, and password.
Uses AES-GCM to verify tag + decrypt.
Restores the original file in Documents (removes .pwdf extension).
📂 Example
Input file:
C:\data\secret.txt
After encryption:
C:\Users<YourUser>\Documents\secret.txt.pwdf
After decryption:
C:\Users<YourUser>\Documents\secret.txt
🛠️ Technologies
C# .NET 6+
System.Security.Cryptography
WinForms
🚀 How to Run
Clone the repository:
git clone https://github.com/baraagabaren/Secure-Files.git
Open the project in Visual Studio.
Run the solution (F5).
Enter a file path + password → click Encrypt File or Decrypt File.
If you enter the wrong password, decryption will fail with an authentication error.
This project is for learning purposes — do not use for production without a security review