---
title: Calculator vault apps: how they work and what they protect
canonical: https://mavaul.com/guides/calculator-vault-apps/
description: A calculator vault looks like a calculator and opens a photo vault when you type a code. The disguise is the easy part. Here's what to check so it protects the photos too.
format: text/markdown
generator: scripts/generate-llms.js
---
# Calculator vault apps, explained

_By [Diogo Ferreira](/about/), founder & engineer_

A calculator vault looks like a calculator on your home screen. Type the right code and a photo vault opens. The disguise is the easy part. What matters is whether the calculator really works, and whether the photos behind it are encrypted or just hidden.

## A calculator that doesn't calculate gives itself away
If someone opens it and types 2 + 2, a fake keypad is obvious. In Mavaul, the calculator lock screen does maths. Type your passcode on the keypad and the vault opens. Long-press the display or the = button to reach the recovery key.

## The disguise isn't the lock
Many calculator vaults keep photos as ordinary files behind the disguise. Check that the listing names its encryption. Mavaul encrypts each photo with AES-256 on the iPhone, so the files are unreadable without your key.

## Set one up in Mavaul
1. Turn on decoy mode (Calculator Disguise) in Settings → Passcode. It's free.
2. With Premium, also change the home screen icon to the calculator, or to a cat or hot sauce if you'd rather not.
3. Open the app, type your 4-digit passcode on the keypad, and you're in.

## Questions
### Do calculator vault apps really work?
As a disguise, yes, if the calculator actually calculates. As protection, only if the photos are encrypted.

### What if I forget the calculator code?
In Mavaul, long-press the display or = to open the recovery key screen, then type your 24-character key.

### Is the calculator lock screen free in Mavaul?
Yes. Changing the app icon is Premium.

## Sources
- [NIST FIPS 197: Advanced Encryption Standard (AES)](https://csrc.nist.gov/pubs/fips/197/final)
- [NIST SP 800-38D: Galois/Counter Mode (GCM)](https://csrc.nist.gov/pubs/sp/800/38/d/final)

## Read next
- [Face ID & passcode](/features/face-id-passcode/)
- [Are photo vault apps safe?](/guides/are-photo-vault-apps-safe/)
- [Handing my phone to my kids](/scenarios/handing-phone-to-kids/)

## Try Mavaul
[Download Mavaul on the App Store](https://apps.apple.com/pt/app/mavaul-photo-video-vault/id6759567727?l=en-GB)