What is the relationship between OpenId Connect and IdentityServer and Identity?

Question

I am confused with AspNetCore Identity,OpenId Connect and IdentityServer4. What is the relationship between them,and what is the suitable occasion for each of them?

Answer 1

• OpenID Connect is a specification (an authentication protocol).
• IdentityServer4 is an implementation of an OpenID Connect provider (server-side)
• ASP.NET Core Identity is a user-management library (over a database). It can be used by an ASP.NET Core application to create users, verify password etc.

OpenID Connect providers using IdentityServer4 are ASP.NET Core applications, so they can use ASP.NET Core Identity to authenticate users on the login page.