Calculator vault apps: is a disguise enough?

A disguise hides the app, not the files

A calculator icon makes an app look ordinary on your home screen. It says nothing about how the files inside are stored. Some vault apps encrypt everything properly. Others only move files to a hidden folder, rename them, or protect them with a short PIN that's easy to guess. From the outside, you can't tell the two apart.

Five questions to ask any vault app

1. Are the files encrypted, one by one, with a modern cipher? Look for AES-256 with authentication (such as AES-GCM), not just "hidden" or "locked".
2. Is the key protected by your phone's hardware? If the key comes only from a short PIN, a copy of the app's storage can be guessed on a computer.
3. Is anything uploaded? Some apps sync to their own cloud by default. Check whether it's opt-in and how it's encrypted.
4. What happens if you forget the code? A safe app gives you a recovery code. An app that can reset your code for you can also be reset by someone else.
5. Does it slow down guessing? After a few wrong tries, the app should make you wait longer and longer.

How Vaultessa answers them

• Every file, file name and folder name is encrypted with AES-256-GCM, using Google's Tink library.
• Each folder's key is wrapped twice: by your pattern and by a key inside the phone's secure hardware (Android Keystore), so the storage alone can't be attacked on a computer.
• Nothing is uploaded. Vaultessa has no servers and no accounts.
• Each folder gets a 32-character recovery code, shown once.
• After 5 wrong patterns you wait 3 minutes, then 6, 12, 24 and so on. Changing the phone's clock doesn't skip the wait.

Can Vaultessa look like another app?

Yes. With Vaultessa Pro you can change the icon and name it shows on your home screen. That's the disguise; the encryption underneath is the same whichever icon you pick. When you open the app it shows a plain dot grid, and each folder opens only with its own pattern.

Questions