Attribute Provider

[Mauro Levra]

Hi everyone and happy new year!

I am currently investigating SAML federated identity scenarios in which
there are - along with Identity Providers - Attribute Providers (AP).

I have not found yet a general consensus about what an AP should or
should not do and, even if some profiles mention them as possible
entities, I have not found any working implementations. To me, one of
the key issues is how to handle user authentication on the AP side.

So, may I ask if some of you could help me clarify the conceptual
definition of an Attribute Provider in a federated identity scenario?
Also, would it be possible to use a modified Shibboleth IdP to implement
a working AP?

Thanks,

-- Mauro