.NET Core: IdentityServer + PolicyServer (new)

podcast & links:
Identity Server Update with Dominick Baier and Brock Allen @.NET Rocks! vNext

IdentityServer : Authentication, free open source tool

PolicyServer : Authorization: free + premium, a new tool 

NDC presentation:
implementing authorization in web applications and APIs - Dominick Baier & Brock Allen - YouTube

Authorization in .NET Core

IdentityServer is creating free open source frameworks for identity and access control | Patreon

Dom's Blog

Azure Active Directory

Azure Active Directory B2C

XACML