Secret Space: a vault we cannot open

AES-256, with the key held in your iPhone’s Keychain and released by Face ID or a PIN. That design has a consequence, and it is stated here before you use it.

iOS has a Hidden album. It is a folder with a lock icon — useful for keeping something out of the way, and not encryption in any sense that would survive scrutiny. The difference is worth understanding whether or not you ever use this feature.

Secret Space is the other thing. Items moved into it are encrypted with AES-256. The key is generated on your device and stored in the Keychain, released only when Face ID, Touch ID or your PIN says so.

The Secret Space screen: 5 encrypted items totalling 10.3 MB, locked and stored only on this iPhone, with warnings that the spare key is not saved yet and the originals are still in the Photos app. — The vault tells you what is not finished yet, rather than looking complete

Vaulting is verified before anything is removed

Moving a photo into the vault is not one step, and the order is deliberate:

The encrypted copy is written into the vault.
It is read back and decrypted.
Its plaintext SHA-256 is compared against the source file.
Only if those match does the original become eligible for removal.

Until you complete that removal, the screen says so out loud — in the capture above, “5 photos are also still in your Photos app”. A vault that quietly left copies behind while looking secure would be worse than no vault, so the app refuses to look finished when it is not.

The honest warning

We hold no copy of your key. There is no account, no server-side backup and no reset, because there is no server. If you lose your PIN and your spare key, the contents of your vault cannot be recovered by anyone, including us.

That is encryption working correctly rather than a fault, and it is the direct cost of the thing that makes it worth using. The app requires you to acknowledge it before setup completes, and it keeps warning you while the spare key is unsaved rather than letting you forget.

Two things follow, and both are in the app:

Save the spare key somewhere else. A password manager, or paper in a drawer. Not a screenshot in the photo library you are about to clean.
Back up the vault. Back Up Secret Space writes an encrypted archive you keep yourself. Without one, a lost or wiped phone takes the vault with it.

What it will not do

It will not sync. The vault lives on this iPhone. There is nowhere for it to sync to, which is the same reason nothing can intercept it in transit.
It will not hide the app itself. Secret Space is visible in SweeperX; it protects contents, not the fact that contents exist.
It will not save you from a forgotten PIN. Repeated as often as it needs to be: nobody can open it for you.

The free tier covers five vault items so you can test the whole flow — encrypt, verify, unlock, restore — before deciding whether to trust it with anything.

Read next: How to Hide Photos on iPhone, and What “Hidden” Really Means — what the built-in Hidden album does and does not protect you from.