What is the difference between MicrosoftAccount, AzureAD and OpenIdConnect authentication?

Question

I got absolutely confused when trying to understand the differences between MicrosoftAccount, AzureAD and OpenIDConnect authentications.

I am trying to build a .Net Core MVC app that allows some users to authenticate with local accounts, but some with Microsoft accounts. I do need to have a local user in DB for both types of authentications as I have some custom authorization mechanisms built on that.

I started with creating the app from template and selected "local accounts" authentication. Then I added the MicrosoftAccount authentication according to this tutorial (https://learn.microsoft.com/en-us/aspnet/core/security/authentication/social/microsoft-logins?view=aspnetcore-3.1). This is using Microsoft.AspNetCore.Authentication.MicrosoftAccount and seems to be working fine.

However, when I create a new app from template and select "work or school account" authentication I can see it uses a different library - Microsoft.AspNetCore.Authentication.AzureAD.UI. It seems to do the same thing. I can see there are events I could hook into to connect the AAD user with my local DB.

Looking through the web I found some other tutorials that were using OpenIDConnect for the same purpose.

How are those methods different? Which one should I use and why?

In future I would like to be able to query the user's directory for a list of other users. Would that requirement be easier met with either of those three methods?

Answer 1

• MicrosoftAccount: This is the login with a general Microsoft account, using OAuth2. This is also what Microsoft will refer to as “private account” and useful when you want to authenticate someone just using their Microsoft login as an external authentication provider. This is similar to how you would sign in to sites with your Google account.
• AzureAD: This is the sign in to a specific Azure tenant. This is often understood as a “work or school account” because it doesn’t sign people in using a public account but rather some account bound to some organization. Usually, you would have an Azure tenant where you have direct users (or configure it to allow external users) but you want to control access through that Azure AD.
• OpenIdConnect: This is the general OpenID Connect protocol which you can use to sign in with many different authentication providers because it is a protocol that many of them will support. You can use OIDC to sign in to either of the above (and many other services) but that will require you to do some more configuration as you will need to figure out specific addresses for example.

You can always use the OpenIdConnect or the OAuth authentication scheme to authenticate with most authentication providers but those are the “manual” schemes which will require you to configure additional things. All the other authentication schemes, including MicrosoftAccount and AzureAD but also the other ones like Google or Twitter build on top of those protocols and come preconfigured so that you do not need to set up much else. So those are mostly for convenience and for more specialized support.

So when you want to authentication through Microsoft or Azure, then you should choose MicrosoftAccount or AzureAD. Which of those depends on where you want to authenticate with. If you have an Azure AD, then you should use that.