NullKey A little understanding
A better routine
Start with the question you have. Keep track of your copies and know how you would recover them.
Private photos
Explore ways to organise and protect private photos.
How to keep private photos on Android
A hidden album may not encrypt photos, while an encrypted vault protects them with a secret. Check every copy first, then practise restoring sample photos.
Read guideAre hidden photos on Android actually safe?
Hiding a photo usually only changes what your gallery shows. The file can still exist on the phone and in a backup, so check every copy first.
Read guideDoes cloud backup copy your private photos?
Automatic photo backup can upload private photos, and a hidden album may still be uploaded, depending on the service. Check its settings before importing.
Read guideWhat should you check before sharing a private photo?
Before sharing a photo, check the picture for names and screens and any embedded location data. Send a cropped copy if the full photo is not needed.
Read guidePrivate documents
Consider where private documents and readable copies are kept.
Where should private documents live on Android?
Locate every copy of a document first, then keep it in an encrypted vault with a checked backup, storing the backup and its secret apart from the phone.
Read guideBefore deleting the original, check the copy
Before you delete an original, check the imported copy and make a checked encrypted backup, because deletion is not guaranteed secure erasure.
Read guideHow do you keep private notes secure on Android?
Know every place your notes live, keep sensitive ones in an encrypted vault, and check the keyboard, clipboard and screenshots, which all sit outside it.
Read guideHow do you keep financial documents private on your phone?
Gather statements and contracts from downloads, email and screenshots into one encrypted vault, and keep the originals until a checked backup exists.
Read guideHow do you keep medical letters private on your phone?
Gather medical letters from email, downloads and photo folders into an encrypted vault, and keep a second copy of anything you cannot replace.
Read guideWhat travel documents should you protect on your phone?
Protect the papers that would stop your trip if lost, then test offline unlock in airplane mode on the phone you will take, a few days before you leave.
Read guideWhere should you keep passport and ID scans on your phone?
Keep one protected master copy of ID scans, such as in an encrypted vault. Delete stray copies only after a backup is checked and restored in a test.
Read guideEncryption and access
Understand access, encryption and the limits of each approach.
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.
Read guideWhat does “no account” mean for a private vault?
With no account there is no reset link, so you keep your own recovery key and encrypted backups. The public app has no server and no internet permission.
Read guideBiometric unlock or passphrase: what do you trade off?
Biometric unlock is quicker each day, but the passphrase stays the root secret, and you need it when a fingerprint or face does not match.
Read guidePassphrase or PIN for protecting private files?
A passphrase of several words is much harder to guess than a short PIN, which matters when someone copies your encrypted files beyond the phone's lockout.
Read guideWhat does 'encrypted' actually mean for your files?
Encrypted data is unreadable until the right key is used. That protects stored files, but not an unlocked phone, a readable export or other apps' copies.
Read guideWhat is Argon2id, in plain English?
Argon2id is a key derivation method that turns your passphrase into a key slowly, using a lot of memory. A weak passphrase stays weak.
Read guideBackups and recovery
Plan how to keep copies and recover access.
How do you back up a vault that stays offline?
Offline does not mean backed up. Create an encrypted backup in Settings, wait for the read-back check, and keep it away from the phone with its secret.
Read guideRecovery key or backup? You need both jobs covered
A recovery key unlocks the vault but is not a copy of your data. A backup holds the data and still needs a valid secret to open it.
Read guideHow often should you back up an encrypted vault?
There is no fixed schedule. Back up after changes you would miss, and keep each backup's own passphrase or recovery key apart from the backup file.
Read guideHow do you test a backup restore before you need it?
Restore a backup of sample files into an empty vault on a spare phone, then check the contents and the secret before you rely on the backup.
Read guideWhat happens if you lose your recovery key and passphrase?
If you lose both secrets, nobody can reset them. An enabled unlock method may still open the vault; otherwise only a backup with its own secret helps.
Read guideWhere should you keep an encrypted backup file?
Keep the encrypted backup physically apart from the phone, with its passphrase or recovery key stored separately, where a new device can reach it.
Read guidePhones and devices
Consider privacy when using or changing a phone.
How to restore a NullKey backup on a new Android phone
Make a checked backup on the old phone, restore it into the new phone's empty vault and keep the old app until the restored vault is checked.
Read guideAre your keyboard and clipboard a risk for private notes?
Yes, they can be. Text you type passes through your keyboard app first, and copied text can sometimes be read by other apps on the clipboard.
Read guideHow do you keep private files private on a shared phone?
On a shared phone, turn off phone screen-lock unlock in the app if others know your lock code, and rely on a passphrase that only you know.
Read guideWhat does a 'readable export' mean for private files?
A readable export is an unencrypted copy outside the vault that the app can no longer protect. Export only what you need and delete it when you are done.
Read guideWhat should you do if you lose your Android phone?
Secure your email and block the SIM first. A locked vault needs an unlock method someone can satisfy, and only a backup kept elsewhere can rebuild it.
Read guide