How do photo vault apps work?
A vault app copies your file in, scrambles it with a key made from your secret, stores the scrambled version inside the app and unscrambles it only while you look at it. The traces that matter are usually the originals you left in your photo library, not anything the vault stores.
The six steps
The steps below describe a well-built vault. A weaker app may skip the encryption step, which is why it is worth knowing what each one should do.
1. Import
You pick photos or videos, or files from the Files app, and the vault makes a copy. On iPhone the system photo picker gives an app only the items you choose, so the vault does not see the rest of your library. The original stays where it was. That is the single most important fact in this guide: importing copies, it does not move.
StrongRoom stores imports as they are, with no recompression. After an import it can offer to delete the originals from your library, and it asks every time. Import and scan photos, videos and files
2. Encrypt
The app scrambles the copy with a cipher. A cipher is a recipe for turning readable data into noise using a key; without the key the noise cannot be turned back. The strength comes from the key, so the real question is where the key comes from. A good design derives it from your pattern or passphrase and does not store it as plain text anywhere. StrongRoom uses AES-256-GCM, and each item has its own key. Encryption you do not have to manage
3. Store
The scrambled file is written inside the app's private storage. Other apps cannot read it. A careful vault also encrypts the things around the file: thumbnails, names and the list of what you have. If those stay readable, someone can learn what you hold without opening anything.
4. View
When you open an item the app unscrambles it, usually in memory, and shows it. While a vault is open its keys exist in memory, and anyone looking at your screen can see what is displayed. A well-built app locks as soon as you leave it, and shows a blank screen in the app switcher so a photo does not sit in the thumbnail of recent apps. StrongRoom locks the moment you leave the app and blanks the switcher.
5. Lock
Locking forgets the keys, so the stored data is noise again. How fast the lock happens, and what it covers, differs between apps. A separate idle timer helps when you walk away with the app open.
6. Delete
Deleting from a vault should destroy the item, and a careful design destroys the item's key so the stored bytes can never be read again. This is called crypto-erase. Deleting an item from the vault does not delete the original you imported; that is a separate action in your photo library.
Where traces remain
- Your photo library. The original, until you delete it. Apple says deleted photos stay in Recently Deleted for 30 days, so empty it if you want them gone sooner.
- iCloud Photos. If it is on, the original was already uploaded, and Apple says photos you delete are deleted on all your devices. Moving a photo into a vault does not remove an earlier cloud copy by itself.
- Device backups. Whether the app's own data goes into iPhone backups is the developer's choice. StrongRoom excludes its data from them.
- The app switcher. A vault that does not cover its screen leaves a thumbnail.
- Exports. A file you share or save out of a vault is an ordinary file from then on.
- Notifications and previews. A vault should not put file names in a notification.
What a vault cannot do
It cannot hide that it is installed, and it cannot stop screenshots or screen recordings. StrongRoom does not disguise itself as another app. If you lose the phone, a vault does not help unless you made a copy: with StrongRoom that is an Export Package, restored on a new iPhone with the Recovery Phrase. What StrongRoom does not protect against
To check an app's claims yourself, see the pillar. -> /guides/choosing-a-vault-app/how-to-choose-a-photo-vault-app/ For the failures to watch for, see the safety guide. -> /guides/choosing-a-vault-app/are-photo-vault-apps-safe/ For a short answer on what happens when you delete a vault app, see the answer page. If I delete a photo vault app, do I lose my photos?
Frequently asked questions
What is a photo vault?
An app that stores your photos, videos and files behind its own lock. A good one also encrypts them, so a copy of the stored data is unreadable without your secret.
Does a vault remove the photo from my camera roll?
Not unless you delete the original yourself or let the app do it. StrongRoom asks every time after an import.
Where does the vault store my photos?
Inside the app's private storage on your phone. StrongRoom keeps nothing anywhere else.
Can the vault see my photos?
The app decrypts them to show you, on your phone. StrongRoom sends nothing off the phone, so the company never receives them.
Sources
- Delete photos on your iPhone or iPad (Apple Support), checked on 2026-10-30.