A hidden folder and an encrypted vault do different jobs

A hidden folder only changes what is visible, while an encrypted vault protects stored files with a secret. Check what is encrypted and how backups work.

Hiding is a visibility choice

An album can disappear from the usual gallery view while its files remain available elsewhere. Do not infer encryption from a hidden icon or a folder name. Check the app’s own documentation for what is encrypted, how it unlocks and what happens to backups.

Ask four questions

What protects the stored files? Who holds the keys? What happens if I forget the secret? How will I move to another phone? Answers are more useful than labels such as “military-grade”. A vault should explain its limits as plainly as its features.

Where NullKey fits

NullKey’s public Android app uses a passphrase, an independent recovery key and encrypted backup files. It has no account and declares no internet permission. Choose it based on those specific properties. For a practical photo routine, read how to keep private photos on Android; for the account and recovery boundary, see what “no account” means. Details of the photo vault feature are here.

Frequently asked questions

What should I ask before trusting a private folder?

Ask what encrypts the stored items, who controls the keys, what you can do if you forget the secret, and how you would migrate to another phone. Vague labels are not an answer, so prefer a product that explains its limits as plainly as its features.

Does a hidden icon mean the files inside are encrypted?

No. Hiding can make an album vanish from the regular gallery, yet its contents may still be reachable through other routes, so a hidden icon or folder name says nothing about encryption. Look for a written account of what is encrypted, how the folder unlocks, and what happens to its backups.

How does NullKey compare with a hidden folder for private files?

NullKey's public Android app relies on a passphrase, an independent recovery key and encrypted backup files, and it has no account. It declares no internet permission, so judge it on those specific properties rather than on labels.

Related guides

Keep a separate, checked backup of important files. Restore only into an empty vault and check the result before removing an original.

Download NullKey from Google Play

Open Google Play on your phone

Updated 8 November 2026 · All guides