FAQ
Frequently asked questions
Short, factual answers about how Open Lock works, what it can and can't do, and how your data is handled.
What is Open Lock?
Open Lock is a free, open-source Android app locker. It guards the apps you choose behind a PIN or fingerprint using Android's standard Usage Access + overlay approach — a Flutter app with native Kotlin enforcement, not an accessibility service.
Is it free?
Yes. Open Lock is completely free, with no ads, no accounts, and no in-app purchases.
Is it open source?
Yes — it's released under the MIT license. The full source, including the native Kotlin enforcement, is on GitHub.
Where is my data stored?
Everything stays on your device. Your config (locked apps, schedules, settings, and the PIN verifier) is encrypted at rest with AES-256-GCM under a key held in the Android Keystore. Intruder photos are kept in app-private storage. Nothing is uploaded.
Does it need internet?
No. Open Lock's core is fully offline. The only optional network use is an update check that contacts GitHub to see if a newer release exists — and it can be turned off in Settings.
Why does it need Usage Access?
Usage Access (PACKAGE_USAGE_STATS) lets Open Lock detect which app is in the foreground via UsageStatsManager, so it knows when a locked app opens.
Why display over other apps (overlay)?
The overlay permission (SYSTEM_ALERT_WINDOW) lets Open Lock draw the native lock screen over a locked app and launch it from the background.
Why device administrator?
Device administrator is optional and only used for uninstall protection. While it's active, Android blocks the normal uninstall flow, and turning it off is auth-gated with your PIN or fingerprint. It's a deterrent against casual removal — a determined user with ADB, Safe Mode, or a factory reset can still remove the app.
How does biometric unlock work?
Fingerprint or face unlock uses AndroidX BiometricPrompt (via local_auth). The PIN remains the source of truth and is always available as a fallback; biometrics are a convenience gate.
What happens after I reboot?
A boot receiver restarts the background guard after a reboot, and everything relocks. Protection resumes automatically without you reopening the app.
How do I unlock an app?
When you open a locked app, Open Lock shows its lock screen over it. Enter your PIN or use your fingerprint. It stays unlocked according to your relock policy — immediately on leaving, after 1/5/15/30 minutes, or when the screen turns off.
What if I forget my PIN?
There is intentionally no "forgot PIN" recovery — a bypass would defeat the lock. If you forget it, the app's data must be cleared, which also clears your locks. Open Lock never stores your raw PIN, only a salted verifier.
How do I report a bug?
Open an issue on GitHub Issues. For security-sensitive reports, please use the GitHub Security tab instead of a public issue.
Where do I download it?
From the Download page, which links to the latest signed release on GitHub.
Is it on Google Play?
Not yet — a Play Store listing is coming soon. For now, install the signed APK from GitHub Releases.