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.
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><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.
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<li><h4>Keep volume open when the app goes in background:</h4>
Don't close the volume when you leave the app but keep running it in the background. Anyone going back to the activity could have access to the volume.
Generate an AES-256 GCM key in the Android Keystore (protected by fingerprint authentication), then use it to encrypt the volume password hash and store it to the DroidFS internal storage. This require Android v6.0+. If your device is not encrypted, extracting the encryption key with physical access may be possible.
* Features requiring temporary writing of the plain file to disk (DroidFS internal storage). This file could be read by apps with root access or by physical access if your device is not encrypted.
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.
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.
Then, retrieve your Android NDK installation path, usually someting like "/home/\<user\>/Android/SDK/ndk/\<NDK version\>". We can now build libgocryptfs:
