OpenId, SAML, IdentityServer
Within IdentityServer4 is a link to Documentation https://identityserver4.readthedocs.io/en/release/ And within that is a link to Videos that has a great one onSupport for Mobility and Javascript
https://github.com/KentorIT/authservices This has some links on supporting Enterprise Partners with SAML, using Okta as an example external IP.
This is a great article setting up Okta for multiple partners: https://github.com/KentorIT/authservices/blob/master/doc/IdentityServer3Okta.md
This is a short description of setting up Kentor as OWIN middleware: https://github.com/KentorIT/authservices/blob/master/doc/OwinMiddleware.md
Go to the "Getting Started" to get info on setting up a development Server
This is used for ResourceAuthorization https://github.com/IdentityModel/Thinktecture.IdentityModel
in StartUp.cs.configureAuth(IAppBuilder app), the call to app.UseResourceAuthorization(IResourceAuthorizationManager) registers an IResourceAuthorizationManager that is used in the ResourceAuthorizeAttribute. It calls a 'CheckAccessAsync' Extension Method on HttpContext or HttpRequestMessage. These use the OwinContext.GetAuthorizationManager() to retrieve the registered IResourceAuthrizationManager, and call it's CheckAccessAsync. This is an override that the applicaiton should provide to check the action and resource paramaters against the ClaimsPrinciple claims. The ClaimsPrinciple is obtain by HttpCOntext.User, or by HttpRequestMessage.GetOwinContext().Authentication.User.
a decent description of OpenID, OAuth and SAML https://spin.atomicobject.com/2016/05/30/openid-oauth-saml/
- The IAuthorizationManager: https://msdn.microsoft.com/en-us/library/microsoft.owin.security.iauthenticationmanager(v=vs.113).aspx