Authenticating Users with ASP.NET Core Identity schema Without ASP.NET Core Identity Library

Hi Everyone,

We have ASP.NET Core application which is authenticating users using ASP.NET Core Identity Library and using ASP.NET Core Identity schema in the database. Now we have developed WPF windows application that also needs to log-in using the same database. So basically we need to login from multipul clients (including none core clients i.e WPF). Can we login user without using ASP.NET Core Identity libraries in WPF app or is ASP.NET Core Identity is required to operate on the same database? 

Please note we cannot introduce a web service in the middle as WPF is a smart client application and can operate in offline mode. It only has access to the local copy of the database in SQL express (in offline mode).

I will appreciate your help.

Please advise.