Latch is a private media vault for Android, written in Flutter. It hides photos, videos, and documents behind PIN/password/biometric auth, encrypts them with AES-256, and removes itself from the recents list when you leave (auto-kill).
Renamed from Locker to Latch. The repo directory is still
Locker, but the app and all user-facing references are Latch. On Google Play: Download Latch.
Vault
- Import from gallery, camera, or files; optionally delete the originals
- Duplicate detection on import
- Per-file encryption settings and compression
- Local backup and restore
Organization
- Nested folders with drag-and-drop, breadcrumbs, and a tree view
- Albums, color-coded tags, favorites
- Grid/list explorer with filters, multi-select, sorting (date, name, size, type)
- Search across name, tags, type, and date
Viewing
- Image viewer (pinch-zoom, slideshow)
- Video player (speed, loop)
- Song player with Flick handoff
- PDF and Office document viewer
- Export to Downloads or external apps
Security
- PIN or password unlock, with biometrics
- AES-256-GCM (default) or AES-256-CTR, with re-encryption of existing files
- Argon2id master-key wrapping; per-file PBKDF2
- Auto-kill, screenshot protection, secure delete
- Decoy vault behind a separate PIN
Theme
- Accent colors, custom theming, glassmorphism unlock screen
Latch is part of the Moss ecosystem. Flick is the companion music
player (UAC 2.0 DAC support). Latch can hand audio playback to Flick and
return via locker://return. Details in the
Flick Integration Guide.
Flutter
| Package | Purpose |
|---|---|
flutter_riverpod |
State management |
flutter_secure_storage |
Credentials and metadata |
pointycastle |
AES-256 encryption |
photo_manager |
Gallery access and import |
pdfrx |
Native PDF rendering |
syncfusion_flutter_pdf |
Office document conversion |
flutter_image_compress |
Image compression |
video_compress |
Video compression |
archive |
ZIP/RAR/7Z support |
permission_handler |
Runtime permissions |
local_auth |
Biometric authentication |
camera |
Photo/video capture |
just_audio |
Audio playback |
in_app_update |
Play Store updates |
Kotlin / Android
| Component | Purpose |
|---|---|
MainActivity.kt |
Auto-kill, performance settings, content URI handling |
AutoKillService |
Removes app from recents when backgrounded |
PermissionHandler |
Runtime permission management |
Prerequisites: Flutter 3.4.4+, Android SDK API 36, JDK 17, Android 8.0 (API 26)+ device.
flutter pub get
flutter run # debug
flutter run -d <device-id> # specific device
flutter build apk --release --obfuscate --split-debug-info=./build/symbols
flutter pub run flutter_launcher_icons # regenerate icons (optional)| Permission | Purpose |
|---|---|
| READ_EXTERNAL_STORAGE / WRITE_EXTERNAL_STORAGE | File access (Android ≤12) |
| READ_MEDIA_IMAGES / READ_MEDIA_VIDEO | Media access (Android 13+) |
| MANAGE_EXTERNAL_STORAGE | Full file access for hide/unhide (Android 11+) |
| CAMERA | Capture photos and videos |
| RECORD_AUDIO | Audio with video |
| USE_BIOMETRIC | Biometric authentication |
Service-based, split into four layers: Services (auth, encryption,
file ops, media), Providers (Riverpod reactive state), Screens
(feature UI), and a Kotlin backend (auto-kill, permissions, camera).
All sensitive data (PINs, passwords, keys) goes through
flutter_secure_storage into Android's Keystore. See
Media Encryption & Compression.
- Media Encryption & Compression: compression, encryption, file ops
- Unlock Autofill: unlock credential autofill and its security model
- Flick Integration Guide: Flick playback handoff contract
Fork → feature branch → flutter analyze + pass tests → pull request.
Follow the Dart style guide.
MIT, see LICENSE. Free, no ads, no paid features.
- @ultraelectronica (creator)
I build this with OpenCode. It writes some of the comments and docs, and it's bailed me out of more than a few nasty-ass bugs. The code, the design calls, and the fuck-ups are all mine.