...It's based on Android fingerprint dialog sample made by Google: https://github.com/googlesamples/android-FingerprintDialog. This library can be used to provide basic authentication through fingerprint API, using manual password as backup option. It also allows you to encrypt messages using fingerprint APIs. This library provides a sample to show how it can be used. key is the name for the symmetric key that is created in the Android Key Store. KFingerprintManager.InitialisationCallback contains a set of method that are called whether the fingerprint is ready to be used or when there is any error (like no fingerprint has been enrolled yet, or if there has been a problem initializing it).