Open Lock

Lock any app behind your PIN or fingerprint — offline.

Open Lock lets you pick the apps that matter and guards them behind a PIN or fingerprint, with focus schedules, device-admin uninstall protection, and an intruder log. Everything runs on-device.

• Maintained by: It Is Unique Official
• Developed by: Jaydatt Khodave
• Website: https://openlock.itisuniqueofficial.com
• Developer: https://jaydatt.pages.dev
• GitHub: https://github.com/itisuniqueofficial-gh/open-lock

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Private by design

Open Lock works offline. Your lock settings and any intruder photos are encrypted on your device — no account, no cloud sync, no ads, no analytics, no tracking. The only network access is an optional check for a newer release on GitHub (see Privacy & Security); it can be turned off in Settings.

Features

Lock what matters

• Pick any installed app from a searchable list with icons and lock it behind your PIN or fingerprint.
• Lock newly installed apps automatically — new installs are caught by the background monitor and locked (see Limitations).
• Choose when apps relock: the moment you leave, after 1 / 5 / 15 / 30 min, or when the screen turns off.

Focus schedules

• Lock a chosen set of apps during time windows — e.g. social apps 9–5 on weekdays, games during study time — enforced by the background guard.
• Same-day, overnight, and all-day windows.

Uninstall protection

• Optional Prevent uninstall uses Android's device-administrator API so the app can't be casually removed. Turning it back off is auth-gated (PIN or fingerprint). See honest limits below.

Stay in control

• Intruder log — after too many wrong attempts, Open Lock can silently take a front-camera photo and log the time and app.
• Anti-shoulder-surfing — optional randomized keypad.
• Escalating cooldown after repeated wrong guesses.
• Optional decoy cover — a fake "app has stopped" dialog; a long-press reveals the real unlock.

Yours to keep

• Encrypted backup & restore (.olbackup) protected by a passphrase you choose.
• Change your PIN and toggle fingerprint unlock from Settings.

How it works

Open Lock uses one of two user-selected, Android-supported enforcement methods:

• Accessibility Service: event-driven window-state notifications identify foreground package transitions. The service requests only typeWindowStateChanged, does not retrieve window content, and is never enabled silently.
• Usage Access: UsageStatsManager is queried from a native foreground service once per second from the last query boundary. Android requires an ongoing notification for this mode, and the lock activity uses the user's overlay permission to appear over the protected app.

Both methods feed one native LockEnforcementManager. It reads the persisted policy without starting Flutter, applies relock and schedule rules, prevents duplicate lock activities, and launches the native authentication screen. The lock screen verifies your PIN against a stored verifier hash (never the raw PIN) entirely on-device, or accepts your fingerprint. Flutter manages configuration, onboarding, app selection, logs, and settings; it is not a foreground-app monitor.

A boot receiver and native package receiver restore supported behavior after a reboot/update and enforce Lock New Apps even when the Flutter UI is closed. Android may still revoke permissions, stop components, or apply OEM battery restrictions; Open Lock reports those actual states instead of pretending protection is active.

Cross-app locking is Android-only by platform design. Real lock behavior requires granting the permissions below on a physical device; it cannot be fully exercised in an emulator or automated test.

Uninstall protection

The optional Prevent uninstall toggle (Settings → Security) is built on Android's device administrator API:

• Enabling it launches the system "activate device admin" dialog. While Open Lock is an active device admin, Android refuses to uninstall it.
• Turning it back off is auth-gated — device admin is only deactivated after a successful PIN or fingerprint check inside the app.
• Best-effort screen guard. While protection is on, the monitor also watches for the OS screens used to disable it (device-admin deactivation, App info / uninstall, the package-installer dialog) and throws up the lock screen first.

Honest limits

The screen guard is best-effort and Android-version / OEM dependent — do not treat it as unbreakable:

• In Usage Access mode it relies on UsageStatsManager reporting foreground events, so there can be a short poll-and-launch window. Accessibility mode is event-driven but still depends on Android delivering accessibility events. OEM skins and newer Android releases may restrict or alter either source.
• Because the App-info screen doesn't reveal which app is being viewed, the guard is intentionally broad and may also prompt when you open another app's info page.
• Device admin blocks the normal uninstall flow, but a determined user with ADB, Safe Mode, or a factory reset can still remove any non-system app. This is a deterrent against casual removal, not a guarantee against a technical adversary with physical access.

Privacy & Security

• Offline core. No accounts, no telemetry, no ads. The only network use is an optional GitHub release check (toggle in Settings).
• Your PIN is never stored. Open Lock keeps only a salted PBKDF2-HMAC-SHA256 verifier hash. The same algorithm runs in Dart and in native Kotlin so the lock screen can check your PIN offline, byte-for-byte identically.
• Encrypted at rest. Your full config is encrypted with AES-256-GCM under a random key held in Android's Keystore (flutter_secure_storage). The subset the native guard needs lives in EncryptedSharedPreferences. If the Keystore is unavailable, Open Lock fails closed — it does not write the verifier to plaintext.
• Screenshot / Recents protection. Both the main app and the lock screen set FLAG_SECURE, keeping sensitive content out of screenshots and the Recents preview.
• Backups off by default. android:allowBackup="false" — app-private data is not included in system/cloud backups.
• Encrypted backups. .olbackup files are encrypted with a separate passphrase (Argon2id-derived key).
• Intruder photos stay on the device, in app-private storage.

Permissions — and why

Permission	Why
Accessibility Service (BIND_ACCESSIBILITY_SERVICE)	Optional user-selected event source; receives only window-state changes to detect a protected app opening. It does not read window content.
Usage access (PACKAGE_USAGE_STATS)	Optional user-selected source; lets the native Usage Access mode detect the foreground app.
Display over other apps (SYSTEM_ALERT_WINDOW)	Required by Usage Access mode to present the lock activity over the protected app. Not required by the selected Accessibility path on supported Android versions.
Foreground service (FOREGROUND_SERVICE / _SPECIAL_USE)	Used only by Usage Access mode because Android requires background execution to be user-visible.
Notifications (POST_NOTIFICATIONS)	Allows the Usage Access service notification on Android 13+; it is not used to hide or suppress required system visibility.
Device administrator (BIND_DEVICE_ADMIN)	Optional — only if you enable Prevent uninstall.
Ignore battery optimization	Optional — keeps the guard alive on aggressive OEM ROMs.
Camera	Optional — silent intruder snapshots if enabled.
Run at boot (RECEIVE_BOOT_COMPLETED)	Restart protection after a reboot.
Install packages (REQUEST_INSTALL_PACKAGES) / Internet	Optional in-app update download from GitHub.
Query all packages (QUERY_ALL_PACKAGES)	List launchable apps you can choose to lock; read locally only.

Protection setup

Open Lock's Protection setup page reports live Android state and guides the user through:

1. Choose Accessibility Service or Usage Access.
2. Use Grant to open the relevant Android Settings page, then return to verify the actual permission.
3. Select apps to lock.
4. Configure the PIN and optional biometric authentication.
5. Review optional battery optimization and security protections.

Accessibility is the lower-resource, event-driven option and does not start an Open Lock foreground service. Usage Access is a supported fallback where the user prefers it, but it uses a one-second native poll and a required foreground service notification. The two methods are not claimed to have identical timing or lifecycle behavior.

Getting started

Prerequisites: Flutter SDK and Android Studio.

git clone https://github.com/itisuniqueofficial-gh/open-lock.git
cd open-lock
flutter pub get
flutter run   # on a connected Android device (recommended over an emulator)

Run the checks the way CI does:

dart format --output=none --set-exit-if-changed .
dart analyze --fatal-infos
flutter test

Build:

flutter build apk --debug
flutter build apk --release        # split per ABI: add --split-per-abi
flutter build appbundle --release  # AAB for the Play Store

The shared core_* packages are pulled from the secure-suite-core repository (a functional dependency). Local development can resolve them by path via a gitignored pubspec_overrides.yaml.

Continuous integration & releases

• CI (.github/workflows/ci.yml) runs on every push and pull request: formatting check, dart analyze --fatal-infos, flutter test, debug and release APK builds, and a release AAB build (uploaded as artifacts).
• Release (.github/workflows/release.yml) runs on v* tags (and manual dispatch): it builds signed universal + per-ABI APKs and an AAB, verifies the signature / package id / version, generates release notes, and publishes a GitHub Release with the artifacts.

Signing uses GitHub Secrets (ANDROID_KEYSTORE_BASE64, ANDROID_KEYSTORE_PASSWORD, ANDROID_KEY_PASSWORD, ANDROID_KEY_ALIAS) — see RELEASING.md. Keystores and key.properties are gitignored and never committed.

Built with

• Flutter & Dart — UI, configuration, schedules, and pure-Dart lock logic.
• Kotlin — native enforcement manager, Accessibility/Usage Access sources, lock activity, package/boot receivers, and device-admin integration.
• Riverpod (state) · go_router (navigation) · local_auth / AndroidX BiometricPrompt (fingerprint) · UsageStatsManager + Accessibility events (enforcement) · DevicePolicyManager (uninstall protection).

Limitations

• No PIN recovery. There is intentionally no "forgot PIN" bypass — a recovery path would be a lock bypass. If you forget your PIN, the app's data must be cleared (which also clears your locks).
• Reliability is best-effort within Android's supported APIs. Accessibility depends on Android delivering window-state events. Usage Access has a short poll-and-launch window and requires its foreground service. OEM background restrictions and battery optimization can affect either method.
• Auto-lock of new apps is handled by a native package receiver, but Android may withhold package broadcasts after the user force-stops an app. Newly installed packages are added to a native encrypted set and do not require Flutter to be open.
• Android can stop applications and users can revoke special access. Open Lock cannot be completely invisible, impossible to kill, guaranteed to run forever, or identical to a system app.
• Package migration. This build's application id is com.itisuniqueofficial.openlock. Installing it over a build that used the previous id is treated by Android as a separate app; data is not migrated.

License

MIT © 2026 It Is Unique Official.