I was trying to setup the new Asp.net Core Identity without Entity framework. Googled a bit and found these stackoverflow answers
http://stackoverflow.com/questions/36095076/custom-authentication-in-asp-net-core http://stackoverflow.com/questions/31271600/asp-net-5-identity-custom-signinmanager http://stackoverflow.com/questions/36184856/authentication-and-authorization-without-entity-framework-in-asp-net-5-mvc-6
All the answers hints at implementing Asp.net Identity Interfaces and making changes in startup.cs. But none of these answers were working for me. Googled a bit more and found this. There is a sample project in the answer which helped a lot even though it doesn’t work with the latest asp.net version. Also after implementing the interfaces using the sample project SignInManager.IsSignedIn(User) method was always returning false. Found the fix here
In all you just need to implement IRoleStore, IUserStore and create CustomUser and CustomRole class and add these lines in Startup.cs
services.AddSingleton<IUserStore<ApplicationUser>, ExampleUserStore>();
services.AddSingleton<IRoleStore<ApplicationRole>, ExampleRoleStore>();
services.AddIdentity<ApplicationUser, ApplicationRole>().AddDefaultTokenProviders();
Here is the working sample of Asp.Net core without EF