decryptWithPassword function

Future decryptWithPassword(Uint8List data, String password, String salt)

Decrypts the data using the provided password and salt.

This function assumes that the first 16 bytes of data are the IV, and the rest is the AES-CBC encrypted payload.

If the password is empty, the data is assumed to be UTF-8 encoded JSON and is decoded directly.

The decryption process is run in a separate Isolate.

Implementation

Future<dynamic> decryptWithPassword(
  Uint8List data,
  String password,
  String salt,
) async {
  return Isolate.run(() {
    if (password.isEmpty) return jsonDecode(utf8.decode(data));

    final iv = encrypt.IV(data.sublist(0, 16));
    final cipherBytes = data.sublist(16);

    final key = encrypt.Key(deriveKey(password, salt));
    final encrypter = encrypt.Encrypter(
      encrypt.AES(key, mode: encrypt.AESMode.cbc),
    );

    final decrypted = encrypter.decrypt(encrypt.Encrypted(cipherBytes), iv: iv);
    return jsonDecode(decrypted);
  });
}