Where these two actually agree
Most comparisons in this category come down to whether the other app encrypts at all. Not this one. Vaultaire encrypts with AES-256-GCM, derives its key from a 5x5 pattern, requires no account, and has a duress code. On the fundamentals the two apps agree, and it is a genuinely good piece of work.
That leaves two real differences.
Every pattern opens a vault
This is the interesting one, and it is Vaultaire's own description of its design rather than our characterisation of it. Its homepage states that every pattern opens a different vault and that there is no master list, no vault count, and no proof other vaults exist. Its manifesto adds that entering the wrong pattern produces no error — just an empty vault — because there is no observable difference between "wrong" and "empty".
That is a deliberate choice and it buys real deniability: nobody can prove you are holding anything back, because the app itself cannot say how many vaults there are.
It also has a consequence worth understanding before you choose it. If anyone picks up your phone and draws a pattern, they get a working vault and can put things in it — and you have no way to find out, because the app keeps no list of vaults to show you. That is not a bug; it follows directly from the feature.
Vaultine works the other way round. An unrecognised pattern or PIN is rejected and nothing opens. The vaults on your device are exactly the ones you created, and your Decoy Vault contains exactly what you put in it. You give up the "no proof anything exists" property, and you get certainty about your own phone in exchange.
Deliberate versus emergent deniability
Both apps answer the same question — what happens when someone makes you unlock — with different mechanisms.
Vaultaire's answer is emergent. Show any pattern, get any vault, and there is nothing to contradict you.
Vaultine's is prepared. The Decoy Vault opens on a second code and shows a vault you stocked in advance, so you know precisely what is revealed. The Duress Vault opens on a third code, shows an empty vault, and wipes your real vaults as it does. You configured both, so neither can surprise you.
Which is better depends on what you are protecting against. Emergent deniability is stronger against someone who suspects a hidden vault exists. Prepared deniability is stronger when you need to know exactly what a search will turn up.
One vault, four platforms
Vaultaire is an iPhone app, with a Mac version described as upcoming. Vaultine runs on Windows, macOS, iOS and Android today, so the documents on a laptop get the same vault as the photos on a phone. In a category that is almost entirely mobile-only, this is the difference that tends to decide it.
