How to confirm device credential before Android 5.0 (API 21)?

Question

I have a use case that requires the user to confirm device credential, and the createConfirmDeviceCredentialIntent method in KeyguardManager perfectly meets my need. However

Answer 1

The best answer I have seen for this situation is described in a blog post:

Android Secrets

However, it recreates system classes that are private and calls AOSP code that is not public. My bounty is for a better answer that would not require explicit Class naming inside the project. Perhaps Smart Lock or another awesome security library can be used for the backward compatibility I require.