AesCipher class final

AES-256-GCM authenticated encryption cipher for quantum_cache.

Security properties:

• Key: 256-bit (32 bytes) — brute-force resistant.
• Mode: GCM (Galois/Counter Mode) — provides both confidentiality and authenticity. Any tampered ciphertext is detected and rejected.
• IV/Nonce: 96-bit (12 bytes) — randomly generated per encryption call. Using a fresh nonce each time prevents nonce-reuse attacks.
• Auth tag: 128-bit (16 bytes) — appended to the ciphertext.

Wire format:

[ 12 bytes ] IV (random nonce)
[ n bytes  ] AES-256-CTR encrypted payload
[ 16 bytes ] GCM authentication tag

Total overhead per value: 28 bytes.

Usage:

final key = AesCipher.generateKey(); // save this securely!
await SuperCache.init(
  config: CacheConfig(encryptionKey: key),
);