DroidFS relies on modified versions of the original encrypted filesystems programs to open volumes. [CryFS](https://github.com/cryfs/cryfs) is written in C++ while [gocryptfs](https://github.com/rfjakob/gocryptfs) is written in [Go](https://golang.org). Thus, building DroidFS requires the compilation of native code. However, for the sake of simplicity, the application has been designed in a modular way: you can build a version of DroidFS that supports both Gocryptfs and CryFS, or only one of the two.
Moreover, DroidFS aims to be accessible to as many people as possible. If you encounter any problems or need help with the build, feel free to open an issue, a discussion, or contact me by [email](mailto:hardcore.sushi@disroot.org) or on [Matrix](https://matrix.org): @hardcoresushi:matrix.underworld.fr
You also need to manually install the [Android SDK](https://developer.android.com/studio/index.html#command-tools) and the [Android Native Development Kit (NDK)](https://developer.android.com/ndk/downloads) (r23 versions are recommended).
If you want a support for Gocryptfs volumes, you must install [Go](https://golang.org/doc/install) and libssl:
```
$ sudo apt-get install golang-go libssl-dev
```
The code should be authenticated before being built. To verify the signatures, you will need my PGP key:
Retrieve your Android NDK installation path, usually something like `/home/\<user\>/Android/SDK/ndk/\<NDK version\>`. Then, make it available in your shell:
```
$ export ANDROID_NDK_HOME="<yourndkpath>"
```
Start by compiling FFmpeg:
```
$ cd app/ffmpeg
$ ./build.sh ffmpeg
```
## libgocryptfs
This step is only required if you want Gocryptfs support.
```
$ cd app/libgocryptfs
$ OPENSSL_PATH="./openssl-1.1.1t" ./build.sh
```
## Compile APKs
Gradle build libgocryptfs and libcryfs by default.
If you want to build DroidFS with support for both Gocryptfs and CryFS, just run:
```
$ ./gradlew assembleRelease
```
# Sign APKs
If the build succeeds, you will find the unsigned APKs in `app/build/outputs/apk/release/`. These APKs need to be signed in order to be installed on an Android device.
If you don't already have a keystore, you can create a new one by running:
DroidFS is an alternative way to use encrypted overlay filesystems on Android that uses its own internal file explorer instead of mounting virtual volumes.
It currently only works with [gocryptfs](https://github.com/rfjakob/gocryptfs) but support for [CryFS](https://github.com/cryfs/cryfs) could be added in the future.
An alternative way to use encrypted virtual filesystems on Android that uses its own internal file explorer instead of mounting volumes.
It currently supports [gocryptfs](https://github.com/rfjakob/gocryptfs) and [CryFS](https://github.com/cryfs/cryfs).
For mortals: Encrypted storage compatible with already existing softwares.
DroidFS is provided "as is", without any warranty of any kind.
It shouldn't be considered as an absolute safe way to store files.
DroidFS cannot protect you from screen recording apps, keyloggers, apk backdooring, compromised root accesses, memory dumps etc.
Do not use this app with volumes containing sensitive data unless you know exactly what you are doing.
# Features
- Compatible with original encrypted volume implementations
- Internal support for video, audio, images, text and PDF files
- Built-in camera to take on-the-fly encrypted photos and videos
- Unlocking volumes using fingerprint authentication
- Volume auto-locking when the app goes in background
_For upcoming features, see [TODO.md](https://forge.chapril.org/hardcoresushi/DroidFS/src/branch/master/TODO.md)._
# Unsafe features
DroidFS allows you to enable/disable unsafe features to fit your needs between security and comfort.
It is strongly recommended to read the documentation of a feature before enabling it.
Some available features are considered risky and are therefore disabled by default. It is strongly recommended that you read the following documentation if you wish to activate one of these options.
<ul>
<li><h4>Allow screenshots:</h4>
Disable the secure flag of DroidFS activities. This will allow you to take screenshots from the app, but will also allow other apps to record the screen while using DroidFS.
Note: apps with root access don't care about this flag: they can take screenshots or record the screen of any app without any permissions.
</li>
<li><h4>Allow opening files with other applications*:</h4>
<li><h4>Allow opening files with other applications*:</h4>
Decrypt and open file using external apps. These apps could save and send the files thus opened.
</li>
<li><h4>Allow exporting files:</h4>
Decrypt and write file to disk (external storage). Any app with storage permissions could access exported files.
</li>
<li><h4>Allow sharing files via the android share menu*:</h4>
<li><h4>Allow sharing files via the android share menu*:</h4>
Decrypt and share file with other apps. These apps could save and send the files thus shared.
</li>
<li><h4>Keep volume open when the app goes in background:</h4>
@ -46,12 +57,12 @@ It is strongly recommended to read the documentation of a feature before enablin
To verify APKs, save the PGP-signed message to a file and run `gpg --verify <the file>`. __Don't install any APK if the verification fails !__
@ -65,17 +76,17 @@ __Don't install the APK if the checksums don't match!__
F-Droid APKs should be signed with the F-Droid key. More details [here](https://f-droid.org/docs/Release_Channels_and_Signing_Keys).
# Permissions
DroidFS need some permissions to work properly. Here is why:
DroidFS needs some permissions for certain features. However, you are free to deny them if you do not wish to use these features.
<ul>
<li><h4>Read & write access to shared storage:</h4>
Required for creating, opening and modifying volumes and for importing/exporting files to/from volumes.
Required to access volumes located on shared storage.
</li>
<li><h4>Biometric/Fingerprint hardware:</h4>
Required to encrypt/decrypt password hashes using a fingerprint protected key.
</li>
<li><h4>Camera:</h4>
Needed to take photos & videos directly encrypted inside DroidFS. You can deny this permission if you don't want to use it.
Required to take encrypted photos or videos directly from the app.
</li>
<li><h4>Record audio:</h4>
Required if you want sound on video recorded with DroidFS.
@ -83,75 +94,24 @@ DroidFS need some permissions to work properly. Here is why:
</ul>
# Limitations
DroidFS use some parts of the original gocryptfs code, which is designed to run on Linux x86 systems: it accesses the underlying file system with file paths and syscalls. However in Android, you can't access other apps files with file paths. Instead, you must use the [ContentProvider](https://developer.android.com/guide/topics/providers/content-providers) API. And obviously, the original gocryptfs code doesn't work with this API. This is why DroidFS can't open volumes provided by other applications, such as cloud storage clients. You can only use DroidFS with volumes located on shared storage or in the app's internal storage (hidden volumes). External storage such as SD cards are only supported in read-only access for now.
# Build
Most of the original gocryptfs code was used as is (written in Go) and compiled to native code. That's why you need [Go](https://golang.org) and the [Android Native Development Kit (NDK)](https://developer.android.com/ndk/) to build DroidFS from source.
- [Android NDK and CMake](https://developer.android.com/studio/projects/install-ndk) (OpenSSL build fails with NDK versions higher than v22. It should pass with NDK v21.4.7075529 and lower)
- [Go](https://golang.org/doc/install) (on debian: `$ sudo apt-get install golang-go`)
DroidFS works as a wrapper around modified versions of the original encrypted container implementations ([libgocryptfs](https://forge.chapril.org/hardcoresushi/libgocryptfs) and [libcryfs](https://forge.chapril.org/hardcoresushi/libcryfs)). These programs were designed to run on standard x86 Linux systems: they access the underlying file system with file paths and syscalls. However, on Android, you can't access files from other applications using file paths. Instead, one has to use the [ContentProvider](https://developer.android.com/guide/topics/providers/content-providers) API. Obviously, neither Gocryptfs nor CryFS support this API. As a result, DroidFS cannot open volumes provided by other applications (such as cloud storage clients), nor can it allow other applications to access encrypted volumes once opened.
Due to Android's storage restrictions, encrypted volumes located on SD cards must be placed under `/Android/data/sushi.hardcore.droidfs/` if you want DroidFS to be able to modify them.
$ go get golang.org/x/sys/unix golang.org/x/sys/cpu golang.org/x/crypto/hkdf github.com/jacobsa/crypto/siv github.com/rfjakob/eme
```
Then, retrieve your Android NDK installation path, usually someting like "/home/\<user\>/Android/SDK/ndk/\<NDK version\>". We can now build libgocryptfs:
Then, open the DroidFS project with Android Studio. \
If a device (virtual or physical) is connected, just click on "Run". \
If you want to generate a signed APK, you can follow this [post](https://stackoverflow.com/a/28938286).
# Building from source
You can follow the instructions in [BUILD.md](BUILD.md) to build DroidFS from source.
# Third party code
Thanks to these open source projects that DroidFS uses:
### Modified code:
- [gocryptfs](https://github.com/rfjakob/gocryptfs) to encrypt your data
- Encrypted filesystems (to protect your data):
- [libgocryptfs](https://forge.chapril.org/hardcoresushi/libgocryptfs) (forked from [gocryptfs](https://github.com/rfjakob/gocryptfs))
- [libcryfs](https://forge.chapril.org/hardcoresushi/libcryfs) (forked from [CryFS](https://github.com/cryfs/cryfs))
- [libpdfviewer](https://forge.chapril.org/hardcoresushi/libpdfviewer) (forked from [PdfViewer](https://github.com/GrapheneOS/PdfViewer)) to open PDF files
- [DoubleTapPlayerView](https://github.com/vkay94/DoubleTapPlayerView) to add double-click controls to the video player
### Borrowed code:
- [MaterialFiles](https://github.com/zhanghai/MaterialFiles) for Kotlin natural sorting implementation
### Libraries:
- [Cyanea](https://github.com/jaredrummler/Cyanea) to customize UI
- [Glide](https://github.com/bumptech/glide/) to display pictures
- [Glide](https://github.com/bumptech/glide) to display pictures
- [ExoPlayer](https://github.com/google/ExoPlayer) to play media files
Here's a list of features that it would be nice to have in DroidFS. As this is a FLOSS project, there are no special requirements on *when* or even *if* these features will be implemented, but contributions are greatly appreciated.
- [Shufflecake](https://shufflecake.net): plausible deniability for multiple hidden filesystems on Linux (would be absolutely awesome to have but quite difficult)
- [fscrypt](https://www.kernel.org/doc/html/latest/filesystems/fscrypt.html): filesystem encryption at the kernel level
## Health
- F-Droid ABI split
- OpenSSL & FFmpeg as git submodules (useful for F-Droid)
- Remove all android:configChanges from AndroidManifest.xml
- More efficient thumbnails cache
- Guide for translators
- Usage & code documentation
- Automated tests
## And:
- All the [feature requests on the GitHub repo](https://github.com/hardcore-sushi/DroidFS/issues?q=is%3Aissue+is%3Aopen+label%3Aenhancement)
- All the [feature requests on the Gitea repo](https://forge.chapril.org/hardcoresushi/DroidFS/issues?q=&state=open&labels=748)