🔐 AES256 #

A lightweight, modern, and secure AES-256-GCM encryption library for Dart & Flutter.
Designed with strong defaults, clean APIs, and seamless usability across mobile, web, and server environments.

👉 Live Demo: https://knottx.dev/aes256

🚀 Features #

• AES-256-GCM — Authenticated encryption with integrity protection
• PBKDF2-HMAC-SHA256 — Strong password-based key derivation
• 100,000 iterations — Secure default against brute-force attacks
• Random salt & nonce — Automatically handled
• Stateless API — Easy to integrate into any architecture
• Pure Dart — Works on Flutter, Dart VM, and Web

🔧 Usage #

import 'package:aes256/aes256.dart';

void main() async {
  // Encrypt
  final encrypted = await Aes256.encrypt(
    text: 'Hello world',
    passphrase: 'my-passphrase',
  );

  // Decrypt
  final decrypted = await Aes256.decrypt(
    encrypted: encrypted,
    passphrase: 'my-passphrase',
  );

  print(decrypted); // Hello world
}

🔒 How It Works #

AES256 outputs a structured, self-contained binary payload:

salt(16) + nonce(12) + ciphertext + tag

Security Parameters #

Why salt & nonce are public #

Salt and nonce do not provide secrecy by themselves — they ensure uniqueness and key strengthening.
The passphrase-derived key is the only secret.
Exposing salt/nonce does not weaken the encryption.

🧪 Example Output (Base64) #

QTI1NkdDTQEBEBcAAAAAAAAAACZ1FqvX…(ciphertext)…Lk5h0nA=

🛡️ Security Notes #

• Always use a strong passphrase
• AES-GCM requires a unique nonce per encryption — this library handles it automatically
• For high-security systems, keep actual keys in secure storage or server-side only

❓ FAQ #

Is the encrypted output safe to store publicly? #

Yes — as long as the passphrase remains secret.

Can I decrypt data encrypted in another language? #

Yes — as long as the other implementation uses the same payload structure and AES-256-GCM + PBKDF2-SHA256 parameters.

This library follows a clean and predictable binary format:

salt(16) + nonce(12) + ciphertext + tag

Any implementation that generates output in the same sequence will decrypt correctly.

Does it work on Flutter Web? #

Yes — it is pure Dart with no native bindings.