Privacy Library PLib

The PLib is a framework for Android that provides functionality to handle personal information appropriately.

• Repository: https://github.com/AppPETs/PLib
• Documentaion: https://github.com/AppPETs/PLib/wiki/Documentation
• Example-App: https://github.com/AppPETs/PLib_Example
• Issues: https://github.com/AppPETs/PLib/issues

Several technologies can be used to enhance privacy, also known as privacy-enhancing technologies (PETs). Many PETs are known in research, but are not easily available to developers. The goal of this project is to make PETs accessible to app developers. The following functionality has been implemented in a way that it can be easily used by application developers.

Functionality

The Privacy Library PLib grants users full control over their data and provides possibilities of encoding, anonymizing and pseudomizing all data exchange. With the intuitive UI provided by this library, the users are able view and modify their data security settings at any given time. On the other side this library is also designed to support novice Android developers who want to implement advanced data and privacy security to their applications/projects. For each user the PLib creates a Master-key which is then used to generate all other keys, seeds, etc. in a deterministic way. It's also possible to import and export the Master-key!

Prerequisites

• Ideally Android Studio (This library can of course be used with other IDEs)
• minSdkVersion 21
• libsodium-jni

Getting Started

You can either download the library directly from github or clone it with the following command:

git clone https://github.com/AppPETs/PLib

To use the Privacy library's code in your app module, proceed as follows in Android Studio:

1. Import the library module to your project (the library source becomes part of your project):

     a. Click File > New > Import Module.

     b. Enter the location of the library module directory then click Finish.

This way the library module is copied to your project, so you can actually view and if needed even edit the library code.
The next step should be done automatically by Android Studio, but make sure everything's configured adequately.

2. Add PLib to your settings.gradle file

Make sure the PLib is listed at the top of your settings.gradle file, as shown here:

include ':app', ':plib'
project(':plib').projectDir = new File('../Android_PLib/plib')

3. Add PLib dependency

Add a new line to the dependencies block in the app module's build.gradle file:

dependencies {
    implementation project(":plib")
}

This can also be done by right-clicking app in the Project view and choosing Open Module Settings.
Next, use the Dependencies tab and click on the + and select Module dependency.
Choose plib and finish the process by clicking Next.

4. Add flatDir

In your projects build.gradle file, add the following code snippet to the allprojects block:

flatDir {
    dirs 'src/main/libs'
}

5. Add libsodium-jni-debug.aar to your app's libs file

Copy the libsodium-jni-debug.aar file from the plib folder src/main/libs to your app's libs folder.
This step will be fixed in the future, so it won't be necessary. But for now it's required.

Implementation

PLib-UI

Implementing the PLib-UI is straigthforward by using PLibApiUi.showPlibUi(MainActivity.this, null). The example below uses a MenuItem to let the users access the PLib-UI.

import de.dailab.apppets.plib.api.PLibApiUi;

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        switch (id) {
            case R.id.action_plib:
                PLibApiUi.showPlibUi(MainActivity.this, null);
                return true;
        }
        return super.onOptionsItemSelected(item);
    }

Make sure to place the entry-point for the PLib-UI visible and reachable at any time for the user.

Access Requests

The PLib let's you easily inform users when your app is about access their personal data. In that case, the user is prompted to allow or deny the access. The code below shows an exemplary AndroidID access. The user's decision will also be saved by the PLib to avoid repeated requests. The class PLibGrantAccess contains many more methods which can be used to access different sorts of private data.

    public static void getAndroidId(final Activity activity, final EditText tv,
                                    final boolean send) {
        PLibAccessCallback<String> cb = new PLibAccessCallback<String>() {
            @Override
            public void grantedData(String grantedData) {
                tv.setText(grantedData == null ? "NULL" : grantedData);
                if (send) {
                    //Send AndroidID
                }
            }
        };
        PLibGrantAccess.getAndroidId(activity, "Please grant access to the android id", cb, true);
    }

Authors

Arik Messerman

Victor Bieszka

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