What's actually different at a border

A search is a search regardless of what's on the phone — Vaultine doesn't change whether you're asked to unlock it. What it changes is what's visible once you do.

A Decoy Vault opens on a second code and shows a set of files you stocked yourself in advance, so an unlock produces something ordinary rather than nothing. A Duress Vault is a separate, third code: it opens empty and wipes your real vaults as it does, for situations where the contents genuinely cannot be seen. And it isn't left as a conspicuous empty shell afterwards: that vault becomes your main vault, as though nothing else had ever been on the device. Both are set up before you travel, not improvised at the checkpoint.

A copy that isn't just on the phone

A lost or confiscated phone is a real possibility on the road, and the vault itself lives on that one device by default. Turning on encrypted backup to your own Dropbox — encrypted before it leaves the device, so it's unreadable to Dropbox or anyone else without your key — means a copy of your files exists somewhere other than the phone that might not make it home with you.

The 12-word recovery phrase covers the other failure mode: forgetting your code partway through a trip doesn't have to mean the vault is gone for good.

One vault, wherever you're carrying files

Passport scans and travel documents tend to end up wherever you happened to be when you photographed them — sometimes the phone, sometimes a laptop packed for the trip. Vaultine runs on Windows, macOS, iOS and Android, so it's the same vault either way, not separate tools you have to keep in sync.