CODEWITHSUNDEEP
flutterdartflutter-blocflutter-cubitflutter-secure-storage
shennan
shennan

Reputation: 11676

Using flutter_secure_storage with hydrated_bloc

I'm developing a flutter app and trying to use flutter_secure_storage with hydrated_bloc. To summarise the packages, flutter_secure_storage is an abstraction to encrypt data on the device, and hydrated_bloc is used with flutter_bloc to persist bloc/cubits (from a runtime store). You can customise the read/write interface of hydrated_bloc, so I figured that I could use them together.

The example on the hydared_bloc page works as expected. Adjusting the counter up and down, then exiting the app and coming back, shows the counter is being read back on startup and is clearly persisting.

But if I add a "Custom Hydrated Storage" with read/write capabilities from flutter_secure_storage, all data is lost on restarting of the app. Here is my "Custom Hydrated Storage":

import 'dart:convert';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:hydrated_bloc/hydrated_bloc.dart';

class CustomHydratedStorage implements Storage {
  final _storage = const FlutterSecureStorage();

  @override
  dynamic read(String key) async {
    final value = await _storage.read(
      key: key,
      iOptions: const IOSOptions(accessibility: KeychainAccessibility.first_unlock),
      aOptions: const AndroidOptions(
        encryptedSharedPreferences: true,
      ),
    );

    print('Reading $key and got $value');

    return value;
  }

  @override
  Future<void> write(String key, dynamic value) async {
    print('Writing $key = $value');
    await _storage.write(key: key, value: value);
  }

  @override
  Future<void> delete(String key) async {
    // TODO: implement delete
    print('HydratedStorage: delete ($key)');
  }

  @override
  Future<void> clear() async {
    // TODO: implement clear
    print('HydratedStorage: clear');
  }

  @override
  Future<void> close() async {
    // TODO: implement close
    print('HydratedStorage: close');
  }
}

Am I missing something here? Is flutter_secure_storage too secure, i.e more configuration is needed in order to use it?

Upvotes: 0

Views: 981

Answers (2)

bara batta
bara batta

Reputation: 1234

you could use built-in encryption in HydratedBloc :

const password = 'hydration';
final byteskey = sha256.convert(utf8.encode(password)).bytes;

HydratedBloc.storage = await HydratedStorage.build(
    storageDirectory: await getApplicationDocumentsDirectory(),
    encryptionCipher: HydratedAesCipher(byteskey));

Upvotes: 0

sheero
sheero

Reputation: 3

I ran into the same problem, after some investigation in the source code of hydration bloc I think I found what is the problem. Flutter secure storage reads the values async but Hive (the default storage used in the hydration bloc) reads values sync. So when the state is being read the result is not being awaited and is always null

Upvotes: 0

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