Biometric and Camera Support for Xamarin Apps on Android

App Live provides biometric and camera injection features for Xamarin apps on Android devices

Overview

BrowserStack offers sensor instrumentation features such as biometric and camera injection by instrumenting android apps. Instrumentation involves the replacement or modification of required Biometric or Camera APIs with our BrowserStack implementation. Some apps use JNI ( Java Native Interface ) or Reflection APIs to call methods, such as Biometric APIs and Camera APIs, due to which BrowserStack is not able to support such apps. This problem majorly occurs with Xamarin apps.

Why do Customers need it?

Customers wants to test biometric and camera injection features on Xamarin apps on Android devices.

How does BrowserStack solve this?

BrowserStack uses Frida for instrumenting Android apps, thus allowing customers to use the biometric authentication feature on devices without any issue.

Instrumentation Process Using Frida

This feature allows you to use BrowserStack biometric feature with Xamarin apps. BrowserStack use Frida to instrument android apps and the way Frida works is it can inject itself during the app startup, and it can hook the methods of classes during runtime. So even if the methods are called using JNI or Reflection, it gets possible to hook the methods, thus allowing the biometric features to work with the Xamarin app.

App Instrumentation Process

1. Determining if the app is built using Xamarin Once you upload the application, it is determined if it is built using Xamarin.

2. Injecting the Frida Gadget in apk If the app is built using Xamarin, Frida is injected into the application

3. Packing the Application Once Frida and suitable libraries are injected, the application is packed and is ready to download on the device.

Advantages of Using Frida

1. Easy to instrument new methods: With Frida, it is easy to hook or change the implementation of class methods with few lines of code.

2. Reduced app patching time

3. Support conditional instrumentation: With Frida, we need to instrument the app once and have a conditional check to enable a particular instrumentation type. This also reduces time spent on patching apps.