How to implement Azure AD B2C authentication in ASP.NET Core 2.0

How to implement Azure AD B2C authentication in ASP.NET Core 2.0
How to implement Azure AD authentication in ASP.NET Core 2.0
How to use ASP.NET Core Identity to authenticate users and manage their accounts.
How to use Identity Server 4 with ASP.NET Core 2.0
How to use Content-Security-Policy header in ASP.NET Core to prevent XSS attacks.
How to prevent Cross Site Request Forgery attacks in ASP.NET Core.