🔒 Private by design

OpenLock runs completely offline. Your lock settings and any intruder photos are encrypted on your device and never leave it — no account, no cloud, no servers, no tracking.

Most app lockers ask for sign-ups, show ads, or phone home with the list of apps you hide. OpenLock doesn't have servers. Everything — which apps you lock, your schedules, your PIN verifier, intruder snapshots — stays on your phone, encrypted.

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
• Choose exactly 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
• Weekday sets, overnight windows, and all-day rules — enforced automatically by the background guard

Uninstall protection 🛡️

• Turn on Prevent uninstall so OpenLock can't be removed on a whim — Android blocks the uninstall until you turn protection back off with your PIN or fingerprint
• See How uninstall protection works below — including its honest limits

Stay in control

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

Yours to keep

• Encrypted backup & restore (.olbackup) protected by a passphrase of your choosing
• Change your PIN, toggle fingerprint unlock, and manage everything from Settings

OpenLock uses the standard, Play-acceptable technique for cross-app locking — Usage Access + an overlay, never an accessibility service:

1. A lightweight foreground service watches which app is in the foreground using Android's UsageStatsManager (polling recent usage events).
2. When a locked app comes to the front and isn't in an unlocked session (per your relock policy and schedules), OpenLock launches a native lock screen over it.
3. The lock screen verifies your PIN against a stored verifier hash (never the raw PIN) entirely on-device, or accepts your fingerprint (the prompt auto-appears each time the lock screen shows, with the PIN pad always there as a fallback), then lets you through.
4. A boot receiver restarts the guard after a reboot.

The main app (app picker, schedules, settings, onboarding) is Flutter with the shared Secure Suite design system; the on-top lock screen is native Kotlin for reliability.

Note: Cross-app locking is Android-only by platform design — iOS does not allow one app to lock another. Real lock behavior requires granting the permissions below on a physical device; it cannot be exercised in an emulator or automated test.

An app lock is only as good as its resistance to being switched off. OpenLock offers an optional Prevent uninstall toggle (Settings → Security) built on Android's device administrator API:

• Enabling it launches the system "activate device admin" dialog. Once OpenLock is an active device admin, Android refuses to uninstall it — the OS itself shows "This app is a device administrator and must be deactivated before you can uninstall."
• Turning it back off is auth-gated. OpenLock will only deactivate device admin after a successful PIN or fingerprint check inside the app. There is no silent deactivation path in the UI — flip the toggle off, prove it's you, and only then is admin removed.
• Best-effort screen guard. While protection is on, the background monitor also watches for the OS screens that could be used to disable it — the Settings → device-admin deactivation screen, this app's App info / uninstall screen, and the package-installer uninstall dialog — and throws up the lock screen (PIN/biometric) over them first.

The screen guard is best-effort and Android-version / OEM dependent — please don't treat it as unbreakable:

• It relies on UsageStatsManager reporting the foreground activity's class name. Some OEM skins and newer Android releases name, reorder, or restrict these screens differently, so the overlay may not always fire in time (there's an inherent poll-and-launch race).
• Because the App-info screen doesn't reveal which app is being viewed, the guard is intentionally broad: it may also prompt for your PIN when you open another app's info/uninstall page while protection is on.
• 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/opportunistic removal — the documented technique app lockers use — not a guarantee against a technical adversary with physical access.
• The device-admin dialog and the guard require the permissions listed below; on devices where they're unavailable the toggle simply won't take effect.

You can always remove protection yourself: toggle Prevent uninstall off (authenticating with your PIN), which deactivates device admin and restores normal uninstall.

• Offline-only. No network code, nothing to leak.
• Your PIN is never stored. OpenLock 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 (locked apps, schedules, settings) is encrypted with AES-256-GCM under a random key held in Android's hardware-backed Keystore (flutter_secure_storage). The subset the native guard needs lives in EncryptedSharedPreferences.
• Intruder photos stay on the device, in app-private storage, and can be deleted any time.
• Encrypted backups. .olbackup files are encrypted with a separate passphrase (Argon2id-derived key) — a backup file alone is useless to anyone else.
• Device admin is used narrowly. OpenLock declares only a minimal policy (to satisfy the schema) purely to block its own uninstall; it never locks, wipes, or manages your device, and deactivation is auth-gated.
• No accounts, no telemetry, no ads.

OpenLock asks only for what cross-app locking genuinely needs, and explains each in-app on a guided checklist:

Prerequisites: Flutter SDK (matching this repo's channel) and Android Studio.

# 1. Clone
git clone https://github.com/MalicKAbdullah/openlock.git
cd openlock

# 2. Install dependencies
flutter pub get

# 3. Run on a connected Android device (recommended over an emulator)
flutter run

Locally, the shared core_* packages are wired as path dependencies to ../../packages. At publish time they point at the secure-suite-core git repository, like the other suite apps.

Build a debug/release APK:

flutter build apk --debug
flutter build apk --release

Run the checks the way CI does:

flutter analyze
flutter test

App icon: a launcher icon can be dropped into assets/icon/ and wired up with flutter_launcher_icons later; the current build ships the default adaptive icon.

• Flutter & Dart — the app UI, config, schedules, and all the pure-Dart lock logic
• Kotlin — the foreground monitor service, native lock activity, device-admin receiver, and boot receiver
• Riverpod (state) · go_router (navigation) · local_auth / AndroidX BiometricPrompt (fingerprint) · UsageStatsManager + overlay (enforcement) · DevicePolicyManager (uninstall protection)
• secure-suite-core — shared encryption, storage & design system

MIT © 2026 Abdullah Malik — part of the Secure Suite.