# How do photo vault apps work?

> A photo vault app copies your photo into its own storage and protects it there. Learn what the key is made from, what stays behind in Photos, and what to ask.

Source: https://vault9app.com/guides/how-do-photo-vault-apps-work/
Updated: 2026-11-12

A photo vault app copies your photo into its own storage and protects it there. Then you delete the original in Photos. How well the copy is protected depends on one thing. Does the app encrypt the file with a key from your secret? Or does it only put a lock screen in front?

## The copy and the original are two files

You pick photos from the Photos app, and the app copies them. Until you delete the original, the photo is in both places, and the vault protects only the copy.

Apple keeps deleted photos in **Recently Deleted** for 30 days, so the original is not gone after the first delete. You can empty it yourself in Photos, under **Utilities**. With iCloud Photos on, a delete applies on all your devices.

## Encryption needs a key, and the key needs a source

Encrypting means scrambling a file so that it cannot be read without a key. A good vault does this to each file before it writes the file to storage.

The question is where the key comes from. If it comes from your pattern or passphrase and the app keeps no copy, the app cannot open your vault. If the app stores the secret or can reset it, the app can open the vault. That is why the "forgot my password" button tells you something: [a reset means the lock was not the key](https://vault9app.com/guides/forgot-photo-vault-password/).

Each time you unlock, the app builds the key again from your secret. It uses a deliberately slow calculation (key stretching), so each guess costs time. In Vault9 the vault locks again when the app goes to the background. The app switcher then shows a plain cover with the logo.

## Four questions to ask any vault app

1. Does it encrypt each file, and does it name the method?
2. Which secret makes the key, and can the company reset it?
3. What happens to its data in your backups?
4. What happens if you lose your phone or forget your secret?

Vault9 answers each one.

## What Vault9 answers

1. Each file has its own key (AES-256-GCM). The app never stores your pattern or passphrase, so it cannot reset it.
2. Your pattern or passphrase goes through PBKDF2-HMAC-SHA512 with 600,000 iterations. You also need a random Secret Key that the phone makes. To open the vault you need both, or Face ID if you turn it on.
3. The vault is not in the iPhone backup or in Quick Start. Its only copy outside the phone is the iCloud backup, which never holds the Secret Key.
4. On a new iPhone, you open the vault from the iCloud backup with the kit. If you forget your secret and did not write it on the [Emergency Kit](https://vault9app.com/emergency-kit/), the vault is lost for good.

You make the kit from the Gallery, and a banner stays there until you save or print it. Vault9 has no account and no servers, so it never receives your photos or your keys. It never deletes or changes anything in Photos, which is why the originals are yours to delete.

Want a vault where you can check each of these answers? Vault9 encrypts every file on your iPhone. The key needs your pattern or passphrase plus the Secret Key, or Face ID if you turn it on. [How Vault9 locks your vault](https://vault9app.com/features/pattern-encryption/) has the details. [Vault9 on the App Store](https://apps.apple.com/app/id6830759639?pt=129716075&ct=how-do-photo-vault-apps-work-md)

## Sources

- [Apple Support: Delete photos on your iPhone or iPad](https://support.apple.com/en-us/104967) (checked 2026-11-06)