I downloaded the APK from apkmirror which I trust: http://www.apkmirror.com/apk/n....
Furthermore, I'm running Android Marshmallow and it allows you to grant or deny specific privileges to each app. This app asked for 4 permissions: contact list, camera, location and storage. This is how you know it's "authentic".
If it's asking for more than that (i.e. microphone), you've got a malware ridden copy.