What is the difference between Azure ACS and Azure AD B2C?

Question

I need to add a custom identity provider to Azure B2C and unsure how to do this.

I know this is possible in Azure ACS, but not sure if B2C is just a "prettier" layer on top of ACS.

Can anyone clarify the difference, and perhaps tell me how I can create a custom IDP for a social network not listed in B2C?

Answer 1

All of the authentication process now is centralized in AAD other options remains temporarily as compatibility services but they will be retired in future.

ACS is migrating to whole AAD feature.

article from 2015 Azure Active Directory is the future of ACS

As you can see in current azure product offerings there is no reference to ACS, even more all the ACS stuff used to be done thru the old Silverlight Azure portal and few things in the 'older' site manage.windowsazure.com.

No references about ACS in the new one

http://portal.azure.com

B2C is oriented to full current standards like OAuth and the authentication model is created to be embraced by web, mobile and desktop developers.

Azure Active Directory B2C

As you can see AAD B2C still in preview, that could be a problem, nevertheless success cases like Real Madrid could give you confidence about to embrace the technology even in early states.

Answer 2

You cannot do this, it is on the wish list and the team is supposedly looking at it.

Note that Azure AD B2C is no longer in preview as it went out of beta late July but even that does not allow you to bring your own IdP, you can only use their social IdPs provided. An alternative is writing your own Auth middleware using IdentityServer or a similar solution.

Answer 3

The ability to add custom identity providers is now in public preview with "Identity Experience Framework" feature. You can add custom policies to integrate with any SAML, OIDC or OAuth based providers, so you can effectively replace ACS with AAD B2C.

B2C Custom Policies Overview