The short answer
The disguise is real and it works on the home screen. It does not work anywhere iOS lists apps by name, and it has nothing to do with whether your photos are readable. If you want a disguise, get one from an app that also encrypts. If the listing does not name its encryption, the calculator is the whole product.
How a calculator vault works
You install an app whose icon and first screen are a calculator. It calculates. When you type a specific code, or a code followed by a symbol, the screen changes to a vault where you keep photos, videos and sometimes notes and passwords. Some apps show a fake crash or an error if the wrong code is typed, so a curious person sees a broken calculator rather than a locked door.
Where the disguise holds
It holds against someone glancing at your home screen or opening the app by accident. It holds in a screenshot of your phone. For a lot of people that is the only case that matters, and the disguise does its job.
Where the disguise breaks
- Settings. iPhone Storage lists every installed app by its real name and size. A 75 MB calculator stands out.
- App Library. Every app appears there under its real name, sorted into categories.
- Screen Time and battery. Both list apps by name.
- The App Store. Anyone who searches the name finds a page that says exactly what the app does.
- The files. A disguise changes the icon. It does not change what is inside the storage, in a backup, or in whatever cloud the app uses.
What the popular calculator vaults say about encryption
Calculator# is the best known. Its listing describes a Panic Switch, a Hack Monitor, a fake crash and backup to iCloud, Dropbox, Google Drive or OneDrive. It does not use the word encryption. Locker offers a calculator or timer icon and says files never leave the phone, and does not mention encryption either. Keepsafe sells a separate Calculator Vault app. Full detail in the Calculator# review and the Locker review.
What to look for instead
A disguise is a feature you can add to a real vault. Kryptis encrypts every file with AES-256-GCM on the phone before it is stored and lets you set the icon to Calculator, Calendar, Clock and more. Behind that, a second passcode opens a decoy vault, a third erases everything, failed unlocks are recorded, and the phone locks when turned face down. The disguise is the front door. The encryption is the reason the door does not matter.
If someone knows the app is a vault
Assume they will. A disguise buys you a moment, not a defence. What protects you after that moment is whether the files are encrypted, whether there is a decoy to open instead, and whether you can erase the vault without warning. Ask those three questions of any app before the icon.
