In Vaultpod there is no list of vaults and no wrong-pattern message. Draw any pattern of six or more dots and a vault opens. If nothing is behind that pattern, the vault is simply empty, and nothing is saved until you add a file.
What that gives you
A decoy for free. Keep a second pattern that opens a vault with a few harmless photos. If you ever have to open the app in front of someone, draw that one. There is no way to tell, from the app or from its files, that another vault exists.
How it holds up
The file that holds the vault keys has the same size and the same random-looking content whether there are zero, one or sixty vaults, and it is rewritten with fresh random filler every time it changes. Encrypted files all live in one folder with random names. What is visible: total storage used and the number of files across all vaults. Vaultpod’s threat model says so.
Free limits
The free plan allows three vaults, counted inside the app, so decoys do not need Pro.