The short answer: Android has three built-in options. Google Photos' Locked Folder hides photos and videos behind your screen lock. Files by Google's Safe folder moves files into a space locked with a PIN or pattern, and Google says that if you forget it, you can't access your files. Samsung phones add Secure Folder. Each one moves files into its own space on that phone. ZapLock locks a folder where it is, on internal storage, a USB drive or Google Drive, and opens it with your sign-in and fingerprint on any of your devices.
Three built-in locks, each with its own space
Google Photos Locked Folder
Moves photos and videos out of your grid into a folder that opens with your screen lock.
- Same unlock as your phone, no separate password
- Items not backed up are lost if you uninstall Photos or clear its data
- Move items out to share them
Files by Google Safe folder
Moves files into a Safe folder locked with a PIN or pattern. Needs Android 8 or later.
- Forget the PIN or pattern and the files are gone
- No Share or Google Drive backup from inside it
- Files can't move to a new phone as-is
Samsung Secure Folder
A separate, Knox-protected space with its own lock for apps and files.
- Only on Samsung Galaxy devices
- Files live inside it, not in your normal folders
- Not shared with your computer
Lock a Google Drive folder from your phone
My Drive/
└── Receipts/
1. download the files
2. encrypt them on the phone
3. upload the locked versions
4. delete the plain originals
Drive keeps deleted originals in its Trash for 30 days, and its version history may keep earlier copies. Empty the Trash to finish.
Google Docs, Sheets and Slides aren't real files on your phone. Download them as .docx, .xlsx or .pptx first, then lock the folder.
ZapLock also locks folders on internal storage and on a USB drive. It asks for All files access so it can encrypt files where they are.
How to lock a folder on Android with ZapLock
From Google Play. Fingerprint or screen lock for the unlock check.
Install ZapLock
Get it from Google Play and sign in with a free ZapQR account.
Allow All files access
Android asks when you lock your first folder. ZapLock needs it to encrypt files where they are instead of copying them into its own space.
Sign in on a second device
Sign in on another phone or computer too. Then losing this phone doesn't lock you out of your folders.
Lock the folder
Tap the menu, choose Add folder… (Protect a folder… in older versions), and pick a folder on internal storage, a USB drive or Google Drive.
Open it with your fingerprint
Turn on Settings → Unlock check to require your fingerprint or screen lock, then tap the folder and unlock it. You view its files inside ZapLock.
What ZapLock won't do
Worth knowing up front, so nothing surprises you later.
- You need a free ZapQR account. That sign-in is what replaces the password.
- Opening a folder needs a connection to our service, which releases its half of the key. A new unlock waits until you're back online.
- If a folder's key lives on only one device and you lose that device, the folder can't be opened. Sign in on a second device before you lock anything you can't lose.
- No Linux, and the apps aren't open source.
- Sync services keep version history. If plain copies were ever synced, your provider may still hold them.
Android folder lock FAQ
What is the best way to lock a folder on Android?
It depends on what's inside. For photos you only view on one phone, Google Photos' Locked Folder is built in. For files that live in normal folders, on a USB drive or in Google Drive, or that you open on more than one device, ZapLock locks the folder where it is and opens it with your sign-in and fingerprint.
What happens if I forget my Safe folder PIN?
Google's help page says that if you forget your PIN or pattern, you can't access your files. ZapLock has no folder PIN to forget: you open folders by signing in, and you can add your fingerprint as a second check.
Can someone read my locked files by plugging my phone into a computer?
Not ZapLock files. They're encrypted on the phone with AES-256-GCM, so a computer, another app or a file manager sees only scrambled data. Google notes that Safe folder files can be reached by someone who gets unauthorized access to the device's internal storage.
Can I lock a folder on a USB drive or SD card?
Yes. Pick the folder on the USB drive with Add folder…. The drive's folder is encrypted in place, so it opens on a Mac or Windows PC with ZapLock too, once one of your devices has handed that computer its key.
Is there a free folder lock app for Android?
Yes. ZapLock's Free plan locks one folder for good, and opening folders, including ones shared with you, is always free. In Google Play, Personal is $4.99 a month or $49.99 a year. See pricing.
Why does ZapLock need All files access?
So it can encrypt the files inside a folder where they already are, instead of copying them into a private app space like Safe folder or Secure Folder do. Without it, Android only lets an app see its own files and a few media folders.
Lock your first folder in a minute.
Free for one folder, for good. On Mac, Windows, iPhone, iPad and Android.
Built-in options checked 22 October 2026 against: Files by Google: Safe folder · Google Photos: Locked Folder · Samsung: Secure Folder.