Calculator app to hide affair photos: how it works and how it is spotted

A calculator app used to hide affair photos is a photo vault disguised as a calculator. It adds, subtracts and divides like a normal calculator, but when you type a secret PIN and press =, it opens a private vault with photos, videos and files. The photos live inside the app's own storage, not in the Photos library. Our pick (we build it) is Stash: Calculator Photo Vault, which encrypts every file on the device with AES-256 and adds a decoy PIN and intruder photos (both Premium).

The disguise works against a quick glance at the Home Screen. It does not make the app invisible. An iPhone still lists the app in App Library, in Search, in iPhone Storage with its size, and in the App Store purchase history. Most people who spot a calculator vault notice exactly those things: a second calculator, or a calculator that takes up far more storage than a calculator should.

This guide explains how these apps work, how they are recognized, and what they cannot protect, so both the person using one and a partner who wonders about one get a clear picture.

How a calculator vault works

1. The calculator is real. Typing 12 × 8 gives 96. Someone who opens the app sees an ordinary calculator.
2. A PIN typed as a sum opens the vault. You enter your code, for example a four- to six-digit number, and press =. Instead of a result, the vault opens.
3. Photos are imported as copies. You pick photos from the library; the vault stores copies in its own encrypted storage. The original stays in Photos until you delete it, and after deletion it stays in Recently Deleted for about 30 days.
4. The vault locks again. When you leave the app or after a set time, it returns to the calculator.

Good vault apps encrypt the files on the device, so the photos are unreadable without the PIN even if someone copies the app's data. Weaker apps only hide a folder behind a fake screen.

How a calculator vault is spotted

Sign	Where it shows
Two calculator icons	Home Screen or App Library (Apple's Calculator is already installed)
A calculator using hundreds of megabytes or more	Settings > General > iPhone Storage
A calculator from an unfamiliar developer	App Store purchase history: Settings > [your name] > Media & Purchases > View Account > Purchase History
Use time on a calculator that seems high	Settings > Screen Time > See All App & Website Activity
Photos missing from the library	Gaps in Photos, or items in Recently Deleted

On iOS 18 an app can also be hidden with Hide and Require Face ID: it moves to a Hidden folder at the bottom of App Library and stops appearing in Search. The Hidden folder itself is still visible, and only third-party apps can be hidden; Apple's own apps can be locked but not hidden.

What a partner can see, and what they cannot

With the phone in hand and the passcode known, a partner can usually see:

• That a calculator vault is installed, and how large it is.
• When it appeared in the purchase history.
• The originals, if they were never deleted from Photos or still sit in Recently Deleted.
• Copies on other devices, if the photos synced through iCloud Photos before being moved.

What they cannot see without the vault PIN is the content of the vault itself, provided the app encrypts it. A guessed PIN is the main risk, which is why a vault PIN should not match the iPhone passcode, a birthday or an anniversary.

What a calculator vault cannot protect

A vault covers only the files you put into it. It does nothing for:

• Messages, call history, contacts and notification previews (Settings > Notifications > Show Previews).
• Photos still in the library, in Recently Deleted, in a Shared Library or on a synced iPad or Mac.
• Location sharing in Find My, payments, email receipts and accounts.
• The other person's phone and anything they save.

It also cannot stop a forensic examination with specialist tools.

If you suspect a partner

A calculator vault on a phone is not evidence of cheating. People keep ID scans, medical photos, bank documents and private pictures in such apps. Opening another adult's phone without permission, or installing monitoring software on it, can be illegal in many countries and is never recommended here. Talk to your partner directly, or with a couples counselor. If you are afraid for your safety, use Safety Check in Settings > Privacy & Security on your own iPhone and reach out to local support services.

How Stash fits

Stash: Calculator Photo Vault is a calculator vault. The calculator works for real sums; your PIN and = open the vault. You can switch its look to a step tracker or a puzzle game, with a matching icon. Face ID or Touch ID can unlock it, and it locks again automatically.

Files are encrypted on the device with AES-256, with the key in the iOS Keychain. There is no Stash server and the developer cannot see or recover your files; a recovery key is shown once at setup. A guest PIN opens a separate guest vault with only what you put there. The optional intruder photo is taken after a wrong PIN and listed in the Intruder Log, and repeated wrong PINs lock the app for 30 seconds, then 5 minutes, then 30 minutes.

The limits above apply to Stash too: it is visible as an installed app, its size shows in iPhone Storage, and it does not stop a forensic examination of the phone.

FAQ

Does a calculator vault app actually work as a calculator?

A good one does. Stash calculates normally, and only your PIN followed by = opens the vault.

Can someone tell a calculator app is a vault?

Often, yes: from a second calculator icon, a large size in iPhone Storage, or the App Store purchase history.

Are photos in a calculator vault backed up to iCloud Photos?

No. They are not in the Photos library, so iCloud Photos does not upload them. Stash offers an optional encrypted backup to your own iCloud Drive or Google Drive, which only runs when you start it.

What happens if I forget the PIN?

Stash shows a recovery key once at setup. Without the PIN or that key, the developer cannot recover the files, because there is no Stash server.