MagSec Encrypter

A Windows desktop app for encrypting text and image files with authenticated, password-based encryption — wrapped in a polished, space-themed UI.

Features

• Text encryption — encrypt/decrypt any text and copy the Base64 result to the clipboard.
• Image encryption — encrypt image files (.png, .jpg, .jpeg, .bmp, .gif, .webp) into a .mseimg container and restore them later, with an in-app preview.
• Up to four access keys — combine 1–4 keys into a single secret; the same combination is required to decrypt.
• Key tools — generate a strong random key, toggle key visibility, and watch a live key-strength indicator.
• Drag & drop — drop an image or a .mseimg file straight onto the window.

Security

MagSec Encrypter uses modern, authenticated encryption from the .NET cryptography stack:

Aspect	Detail
Cipher	AES-256-GCM (authenticated encryption)
Key derivation	PBKDF2-HMAC-SHA512, 600,000 iterations
Salt	16 bytes, random per operation
Nonce	12 bytes, random per operation
Auth tag	16 bytes
Header integrity	The full header (format prefix, version, KDF parameters, salt, nonce) is bound into the GCM tag as associated data, so any tampering is detected on decrypt.
Memory hygiene	Derived keys and secret bytes are zeroed (CryptographicOperations.ZeroMemory) after use.
Key policy	A minimum combined key length is enforced to discourage weak secrets.

Payload format

Encrypted output is a self-describing v2 binary payload (Base64-encoded for text):

prefix(4) | version(1) | kdfId(1) | iterations(4, big-endian) | salt(16) | nonce(12) | tag(16) | ciphertext

Storing the KDF parameters in the header provides crypto agility — the work factor or hash can change in future versions without breaking existing files. Legacy v1 payloads (TXT1 / IMG1) remain decryptable for backwards compatibility.

⚠️ There is no key recovery. If you lose your key combination, the data cannot be decrypted. Store your keys somewhere safe.

Requirements

• Windows
• .NET 10 SDK (target framework net10.0-windows)

Build & run

dotnet build
dotnet run

Or open the project in Visual Studio and press F5.

Usage

1. Enter one or more access keys in the left rail (or click Generate for a strong random key).
2. Text: type or paste into the Input box, then Encrypt / Decrypt. Use Copy output to grab the result.
3. Images: Open image → Encrypt image to save a .mseimg file. To restore, Open encrypted file → Decrypt image.
4. Use the same key combination for decryption that you used to encrypt.

Project layout

File	Purpose
Form1.cs	App logic, cryptography, custom controls, and the animated background
Form1.Designer.cs	WinForms layout
Program.cs	Entry point
TextEncryptorApp.csproj	Project configuration

License

No license has been specified for this project.