Flutter: PlatformException(Exception encountered, deleteAll, java.lang.IllegalArgumentException: bad base-64

Question

I use the secure storage package to store data relevant to my app usage.

Recently I created some new features not related to that package and everything works perfectly on development environment. But after deploying the app on the google play store, I get an error when trying to use secure storage.

After clicking on the login button, I try to clean the secure storage using the clear function from the code below.

When I do that, I get an error:

PlatformException(Exception encountered, deleteAll, java.lang.IllegalArgumentException: bad base-64  at 
u4.e.c(Unknown Source:37)  at 
u4.e.b(Unknown Source:2)  at 
u4.e.a(Unknown Source:6)  at 
androidx.security.crypto.a.c(Unknown Source:3)  at 
androidx.security.crypto.a.getAll(Unknown Source:49)  at 
androidx.security.crypto.a$b.a(Unknown Source:11)  at 
androidx.security.crypto.a$b.apply(Unknown Source:0)  at 
s6.a.e(Unknown Source:23)  at s6.e$b.run(Unknown Source:135)  at 
android.os.Handler.handleCallback(Handler.java:942)  at 
android.os.Handler.dispatchMessage(Handler.java:99)  at 
android.os.Looper.loopOnce(Looper.java:240)  at 
android.os.Looper.loop(Looper.java:351)  at 
android.os.HandlerThread.run(HandlerThread.java:67) , null)

On the moment that the error triggers the storage has 2 values in it that would be cleaned. An email and a JWT token.

So far the error only happens on my own smartphone (OnePlus 8 Pro + Oxygen OS 13) and on this new version installed from the play store. Other people haven't been able to reproduce the error I get. Also, the code that now gives me this error exists, implemented exactly as in this version, on the app since the first version (I already updated the app a few times) and i never had that error before.

My secure storage implementation

class SecureStorageService {
  static final SecureStorageService _instance =
      SecureStorageService._internal();
  late FlutterSecureStorage flutterSecureStorage;

  SecureStorageService._internal() {
    flutterSecureStorage = const FlutterSecureStorage(
        aOptions: AndroidOptions(
      encryptedSharedPreferences: true,
    ));
  }

  static SecureStorageService get getInstance => _instance;

  Future<bool> set({required String key, required String value}) async {
    await flutterSecureStorage.write(
      key: key,
      value: value,
    );
    return true;
  }

  Future<String?> get({required String key}) async {
    return flutterSecureStorage.read(key: key);
  }
  
  Future<bool> clear() async {
      await flutterSecureStorage.deleteAll(
          aOptions: const AndroidOptions(encryptedSharedPreferences: true));
    return true;
  }
}

Things I already tried based on some research:

• adding aOptions: const AndroidOptions(encryptedSharedPreferences: true)
• update flutter to its latest version 3.3.10
• update storage package to its latest version 7.0.1
• tried to play with android:allowBackup and android:fullBackupContent

Another thing I noticed is that if I clear the app data on the android, the error does not happen. But if I uninstall and install the app again, the error comes back until I clear the app data again

Considering the fact that cleaning the app's data from android "solves the problem", I tried to do that programmatically with things like:

await DefaultCacheManager().emptyCache();

Future<void> _deleteCacheDir() async {
  final cacheDir = await getTemporaryDirectory();
  if (cacheDir.existsSync()) {
    cacheDir.deleteSync(recursive: true);
  }
}

Future<void> _deleteAppDir() async {
  final appDir = await getApplicationSupportDirectory();
  if (appDir.existsSync()) {
    appDir.deleteSync(recursive: true);
  }
}

But it didn't work. I think that what I'm doing through code is probably not equivalent to what android does.