encrypt method
Encrypt bytes.
Implementation
@override
Encrypted encrypt(Uint8List bytes, {IV? iv, Uint8List? associatedData}) {
  if (iv == null) {
    iv = IV.fromSecureRandom(16);
  }
  int currentTime = (_clock.now().millisecondsSinceEpoch / 1000).round();
  final encryptedBytes = _encryptFromParts(bytes, currentTime, iv);
  return Encrypted(encryptedBytes);
}