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.
latchd is a tiny companion you run on your desktop. It hosts a local
web UI (http://127.0.0.1:7800, loopback only), shows a pairing QR, and
receives encrypted vault backups from the phone over Wi-Fi or USB — no
server, no accounts, ciphertext only in transit. It can also browse,
verify, restore, and export-decrypt a backup.
Linux (amd64 / arm64) — one-line installer, installs to
~/.local/bin/latchd with sha256 verification:
curl -fsSL https://raw.githubusercontent.com/moss-apps/Latch/HEAD/scripts/install-latchd.sh | bashInstaller overrides (environment variables): LATCHD_BINDIR (install
directory), LATCHD_VERSION (pin a release tag, e.g. 0.18.0-beta.1),
LATCHD_REPO (alternative fork).
Windows — download latchd-windows-amd64.exe from
releases.
From source — needs Go; no repo clone required for the installer paths above:
make latchd # builds ./latchd/latchdmacOS is not supported yet (prebuilt binaries are Linux/Windows only).
latchd needs no config file. Subcommands and their options:
| Command | Purpose | Options |
|---|---|---|
latchd serve |
Loopback web UI: pairing QR, browse, restore | --addr 127.0.0.1:7800 (listen address), --dir latch-backup (backup directory) |
latchd verify |
Verify a local backup against its manifest | --dir latch-backup, --password |
latchd export-decrypted |
Decrypt a local backup to plaintext | --out <dir> (required), --dir latch-backup, --password |
latchd version |
Print the build version | — |
The vault password comes from --password, the LATCHD_PASSWORD
environment variable, or an interactive prompt. It is never stored and
kept in memory only — prefer the prompt or env var over the flag.
Network defaults:
- Web UI:
127.0.0.1:7800, loopback only — never exposed to the LAN. - Pairing receiver:
0.0.0.0:7801(fixed port so one firewall rule covers every session; falls back to an ephemeral port if taken). It exists only while a pairing session is active and is token-gated. On Linux/ufw, latchd prints the exact rule at session start, e.g.sudo ufw allow from <lan-subnet> to any port 7801 proto tcp. - USB:
adb reverse tcp:<port> tcp:<port>(shown in the web UI), then tap Connect via USB on the phone and Allow once on the desktop.
- Run
latchd serveand open http://127.0.0.1:7800 - Start a pairing session (if your firewall asks, latchd prints the exact rule)
- Phone: Latch → Settings → Storage → Desktop Backup → scan the QR
Full spec: docs/desktop_backup.md.
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.