Every pattern opens a vault

In Locked, every pattern or password opens its own vault. Draw your real pattern and your vault opens; draw another and a different vault opens. A pattern that opens nothing shows an empty vault that looks like a real one, not an error message. So you can keep a decoy with harmless photos and give that pattern if you are pressed. A phone holds up to 16 vaults, 3 without Locked Pro.

How does a decoy vault work?

There is no list of vaults and no switch between them. Each one is opened by its own secret, from the same lock screen. Put a few ordinary photos in one and that is your decoy: if someone insists you open Locked, open that.

A pattern that opens nothing does not say so. It shows an empty vault that looks like a real one, so a guess looks like it worked.

Can someone tell how many vaults I have?

The vault files are built not to say: the keys live in one fixed-size table of 16 slots, and unused slots are random bytes that look like used ones. But there are limits, and the app names them too.

Someone who can open one vault could count the others by setting up new vaults until there is no room. Without Locked Pro, all vaults share one allowance of 101 photos, 10 videos, 10 files and 10 notes, so a vault that runs out of room early shows that others hold items. The storage Locked uses shows in the Settings app. Two copies of an iCloud backup taken at different times show how many vaults changed in between. And someone with full forensic access to an unlocked device could read which slots are in use.