Sealby

Sealby is a privacy vault app for iPhone and iPad built around a strict zero-knowledge design: files are encrypted on the device with AES-256-GCM (one key per file, protected by the Secure Enclave), there is no account to create and no server holding your data, and the optional iCloud sync moves only an unreadable encrypted blob. The feature that sets it apart from the long list of 'photo hider' apps is deniability — you can set up hidden vaults where a different PIN opens a different vault, with no stored list or count of how many vaults exist, and the Premium tier adds a duress PIN that opens a decoy vault under pressure. For anyone who has ever had to hand an unlocked phone to someone, that design is meaningfully stronger than a simple PIN lock. Each vault has its own recovery phrase rather than a master key, which removes the single point of failure but puts the burden of safekeeping entirely on you — lose the phrase and the data is gone; that is the honest trade-off of zero-knowledge systems, not a flaw. The free tier is genuinely usable (unlimited vaults, up to 100 files per vault, every file type plus rich-text notes), with Premium removing the cap and adding encrypted multi-device sync and vault sharing. It is not an AI tool in the generative sense — it is on-device cryptography — but for privacy-conscious users it is one of the more carefully architected vault apps on iOS, and the free tier is enough to evaluate it properly.