Secure File Manager

Open-source Android file manager for hiding, encrypting, and locking down your files.

Secure File Manager is an open-source Android file manager focused on keeping your files safe: hide files from the gallery/media scanner, encrypt files and folders, lock the app with a password or biometrics, and manage everything with a modern Material 3 interface. Based on Simple File Manager and part of the OnionPhone app family — this fork rebrands the app (ltechnologies.onionphone.securefilemanager) and is gradually converting the codebase to Kotlin.

‼️ This app is useless if you have a rooted device!

This is a beta version of the app. Do not use it with important files yet — the developers are not responsible for data loss or corruption.

✔️ Open source · ✔️ Privacy friendly · ✔️ Free · ✔️ No ads · ✔️ No unnecessary permissions

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Table of contents

• Features
• Architecture
• Install from GitHub Releases
• Build it yourself
• API documentation (KDoc)
• Screenshots
• Security
• Contributing
• License

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Features

Feature	Description
Hide files	Hide files/folders from the gallery and other apps without moving them off-device
Encrypt files	Encrypt individual files, or create/extract password-protected encrypted Zip archives
App lock	Password or biometric authentication to open the app (optional)
Checksums	Compute MD5, SHA1, SHA256, SHA512 for any file
Privacy hardening	Disable screenshots, disable thumbnails, clear cached thumbnails (all optional)
Media destinations	Choose where new photos/videos are saved
Remote storage	Connect to SFTP servers
Localization	English, French, Spanish (community), Japanese, Russian, Danish (partial)

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Architecture

Single-module Gradle project — see docs/ARCHITECTURE.md for the full package layout and feature map.

:app
 └── ltechnologies.onionphone.securefilemanager
      ├── activities / fragments / dialogs / views   (UI)
      ├── adapters                                    (RecyclerView)
      ├── storage / transfer / providers              (file I/O, SFTP, encryption)
      ├── helpers                                      (config, logging, hashing)
      └── models / interfaces / observers / receivers / services

Layer	Technologies
UI	Android Views + ViewBinding, Material Components
Async	Kotlin Coroutines
Encryption	Argon2Kt (key derivation), Zip4j (encrypted archives)
Remote storage	sshj (SFTP)
Thumbnails	Glide
Dependency auditing	OWASP dependency-check Gradle plugin
Licenses UI	AboutLibraries

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Install from GitHub Releases

1. Open Releases.

2. Download the APK matching your device CPU:

   APK suffix	Devices
   arm64-v8a	Most modern phones (2017+)
   armeabi-v7a	Older 32-bit ARM phones
   x86_64	Emulators, some tablets
   x86	Older emulators

3. Enable Install unknown apps for your browser/files app.

4. Install the APK.

Release APKs are signed with the project release key when CI secrets are configured. Verify the signature with apksigner verify.

Also available on F-Droid for the upstream app id.

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Build it yourself

Prerequisites

Tool	Version
JDK	17 (Temurin recommended)
Android SDK	API 37, Build-Tools 36+
Gradle	9.x (wrapper included)

Set ANDROID_HOME / ANDROID_SDK_ROOT and create local.properties:

sdk.dir=/path/to/Android/Sdk

Optional: copy secrets.properties.example to secrets.properties if you need BrowserStack device-farm testing (./gradlew connectedDebugAndroidTest on BrowserStack — not required for a normal build).

One-shot commands by OS

Linux / macOS

# Clone
git clone https://github.com/LTechnologies0/Secure-File-Manager.git && cd Secure-File-Manager

# Debug APK (arm64-v8a, fastest)
./gradlew :app:assembleDebug

# All unit tests
./gradlew test

# Release APKs — all 4 ABIs (unsigned without keystore)
./gradlew :app:assembleRelease

# Release APKs — signed locally
cp keystore.properties.example keystore.properties
# Edit keystore.properties, then:
./gradlew :app:assembleRelease

# Install debug on connected device
./gradlew :app:installDebug

# API documentation
./gradlew dokkaGenerate
# → build/dokka/html/index.html

Windows (PowerShell)

git clone https://github.com/LTechnologies0/Secure-File-Manager.git; cd Secure-File-Manager

# Debug APK
.\gradlew.bat :app:assembleDebug

# Tests
.\gradlew.bat test

# Release (all ABIs)
.\gradlew.bat :app:assembleRelease

# Install debug
.\gradlew.bat :app:installDebug

# Docs
.\gradlew.bat dokkaGenerate

There are also ready-made PowerShell helper scripts: scripts/setup-and-install.ps1 and scripts/install-to-device.ps1.

Output paths

Task	Output
assembleDebug	app/build/outputs/apk/debug/app-<abi>-debug.apk
assembleRelease	app/build/outputs/apk/release/app-<abi>-release.apk
dokkaGenerate	build/dokka/html/index.html
test	**/build/reports/tests/

Local release signing

bash scripts/generate-release-keystore.sh
cp keystore.properties.example keystore.properties
# Edit paths/passwords — never commit these files
./gradlew :app:assembleRelease

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API documentation (KDoc)

Public APIs are documented with KDoc in source. HTML reference is generated with Dokka:

./gradlew dokkaGenerate
# → build/dokka/html/index.html

Live docs (auto-deployed on push to main): ltechnologies0.github.io/Secure-File-Manager

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Screenshots

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Security

• No secrets in repo: keystore.properties, secrets.properties, and local.properties are gitignored — see SECURITY.md.
• CI signing: GitHub Actions secrets only.

GitHub secret	Purpose
RELEASE_KEYSTORE_BASE64	Base64-encoded keystore
RELEASE_KEYSTORE_PASSWORD	Keystore password
RELEASE_KEY_ALIAS	Key alias
RELEASE_KEY_PASSWORD	Key password

Enable in repo settings: Dependabot alerts, secret scanning, push protection, CodeQL.

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Contributing

See CONTRIBUTING.md. In short:

1. Fork and create a feature branch from main.
2. Run ./gradlew test :app:assembleDebug before pushing.
3. Add KDoc for new public APIs.
4. Open a PR — CI runs tests, debug build, CodeQL, and dependency review.

Translations happen on Crowdin. See FAQ and CHANGELOG.md for release history.

Acknowledgments ❤️

This app is based on the Simple File Manager, continued via Secure-File-Manager/Secure-File-Manager.

Open-source components used: AboutLibraries · AppIntro · Argon2Kt · TapTargetView · Zip4j · Glide · sshj

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License

Licensed under the GPLv3.

F-Droid logo is a trademark of F-Droid Limited. GitHub logo is a trademark of GitHub Inc.