Best app to hide an affair from a spouse: what to check first

No app can hide an affair. What an app can do is protect specific photos, videos and files behind a separate PIN with encryption on the device. The best app for that is one that encrypts locally, has a PIN separate from the iPhone passcode, keeps nothing on the developer's server, and tells you honestly what it cannot cover. Our pick (we build it) is Stash: Calculator Photo Vault: on-device AES-256, a PIN separate from the passcode behind a working calculator, no Stash server, plus a decoy PIN and intruder photos (both Premium).

That last point matters most. Messages, calls, location sharing, purchase records, receipts in email and anything on another person's phone sit outside any vault. An app that promises otherwise is promising something it cannot deliver.

Below are seven criteria to judge a vault app, a checklist, what a spouse can and cannot see, and a section for the other side.

Seven criteria for a vault app

1. Real encryption on the device. The app should name its encryption (for example AES-256) and say where the key is kept. Vague wording like "secure storage" tells you nothing.
2. A PIN separate from the iPhone passcode. This is the main gap in the built-in Hidden album: anyone who knows the iPhone passcode can open it. A vault should need its own code.
3. No account and no company server. If the developer stores your files or keys, the developer can, in principle, see or lose them. Zero-knowledge means the developer cannot see or recover your files.
4. A believable disguise. A calculator that really calculates, or another ordinary tool, is less eye-catching than an icon labeled "vault".
5. A second PIN (decoy). A guest or decoy PIN opens a different vault that holds only harmless items. See what a decoy password is.
6. An intruder log. A record of failed attempts, ideally with a photo, tells you whether someone tried.
7. Backups you control, and a recovery plan. Backups should go to your own cloud storage, only when you start them. If the developer cannot recover anything, a recovery key written down at setup is the only safety net.

Vault apps compared on these criteria

Best for	App	Encryption stated by vendor	Own PIN	Decoy PIN	Break-in photo	Calculator disguise
Our pick	Stash: Calculator Photo Vault	AES-256, on device	Yes	Yes (guest PIN, Premium)	Yes (opt-in, Premium)	Yes
A few photos, nothing to install	Apple Hidden album	Not stated (locked with Face ID or Touch ID)	No, opens with the iPhone passcode	No	No	No
Encrypted cloud copy	Proton Drive	End-to-end, encrypted on device before upload	PIN lock in the app	Not stated	Not stated	Not stated
iPhone and Android	Keepsafe	AES-256, on device and in backup (products page)	Yes	Not stated	Tracks break-in attempts (Premium); photo not stated	Separate Android-only app
Break-in photo with GPS	Private Photo Vault	AES, on device, own key	Yes	Yes	Yes, photo and GPS	Not stated
Open about its crypto	Obscura Photo Vault	AES-256-GCM, PBKDF2	Yes	Yes (separate vaults)	Not stated	No

Sources: each vendor's own pages, read on 8 October 2026, re-checked on 10 October 2026 and linked in our comparison of photo vault apps for iPhone. "Not stated" means the vendor does not say; it does not mean the feature is missing. Disclosure: we build Stash.

Competitor details last checked: 2026-10-10, from each vendor's own pages.

Our verdict: Stash: Calculator Photo Vault is our pick here, because it combines stated AES-256 on-device encryption, a PIN separate from the iPhone passcode, a guest PIN, an intruder photo and a working calculator disguise. Choose Private Photo Vault if a break-in report with GPS matters most to you, or Keepsafe if you also use Android.

Quick checklist before you trust an app

• Does it copy or move files on import? If it copies, delete the original from Photos yourself and then empty it from Recently Deleted, where it would otherwise stay for about 30 days.
• Does it upload anything to the developer?
• What happens after several wrong PINs?
• Can it be locked with Face ID or Touch ID, and does it lock automatically when you leave it?
• What does it say about its own limits?

What no app can hide

Even a well-built vault app leaves these untouched:

• The app itself: it is visible in App Library, in Search (unless hidden with iOS 18), in Settings > General > iPhone Storage with its size, and in Settings > [your name] > Media & Purchases > View Account > Purchase History.
• Conversations: messages, calls, notification previews (controlled under Settings > Notifications > Show Previews), and Messages in iCloud on any shared iPad or Mac.
• Location: Find My location sharing and Significant Locations.
• Money: card statements, Wallet, email receipts, booking confirmations.
• Other people's devices: whatever the other person keeps, sends or screenshots.

What a spouse can and cannot see

A spouse who knows the iPhone passcode can open the Hidden album and Recently Deleted, see every installed app and its size, read per-app usage in Settings > Screen Time > See All App & Website Activity, and check purchase history. If the two of you share an Apple Account, they may see photos and messages on a shared iPad, Mac or iCloud.com. Apple recommends that each person use their own Apple Account.

A spouse without the vault PIN cannot open files inside a vault app that encrypts them. They can see that the app is there, and a guest vault can be suspected by someone who knows how these apps work.

If you suspect a partner

A vault app on a phone is not evidence. Many people keep ID scans, medical documents, finances or personal photos in one.

If you are worried, a direct conversation or couples counselling is more likely to get you an answer than searching a device. Accessing another adult's phone without permission, or installing monitoring software on it, can be illegal in many countries; this site does not recommend any such tool.

If your safety is at risk, Safety Check (Settings > Privacy & Security > Safety Check, iOS 16 and later) reviews and stops what you share with people and apps. Apple built it for people facing domestic or intimate partner violence. Local support services can help further.

How Stash fits

Here is how Stash: Calculator Photo Vault measures against the seven criteria. Encryption: AES-256 on the device, key in the iOS Keychain. Separate PIN: yes, typed into a working calculator, with Face ID or Touch ID as an option and auto-lock. Server: none; the developer cannot see or recover your files. Disguise: calculator, step tracker or puzzle game, with a matching icon. Decoy: a guest PIN opens a separate guest vault. Intruder log: optional, with a front-camera photo after a wrong PIN; repeated wrong PINs lock the app for 30 seconds, 5 minutes, then 30 minutes. Backups: optional, encrypted, to your own iCloud Drive or Google Drive, only when you start them. Recovery: a recovery key shown once at setup.

Import copies the file, so the original stays in Photos until you delete it. And Stash, like every vault, protects files only.

FAQ

What is the best app to hide an affair from a spouse?

No app hides an affair. For protecting photos and files, our pick is Stash: Calculator Photo Vault: AES-256 encryption on the device with the key in the iOS Keychain, its own PIN behind a working calculator, no Stash server, plus a guest PIN and intruder photos with Premium. Whatever you choose, look for on-device encryption, its own PIN, no developer server and an honest list of limits.

Is the iPhone Hidden album enough?

It keeps photos out of the Library, but it opens with the iPhone passcode and syncs to every device on the same Apple Account. A vault app adds a separate PIN.

Can a spouse find a vault app?

Yes. Every app is visible in iPhone Storage and in App Store purchase history. A disguise only makes it look ordinary at first glance.

What happens if I forget my vault PIN?

That depends on the app. With a zero-knowledge vault, the developer cannot reset it for you; only a recovery key you wrote down at setup helps.