> In response to an attribute query, if no attributes for the principal
> are available, it seems the IdP should return an empty response.
Well, if you consider a Status message empty...
> In SAML V2.0, does it make sense to return an empty assertion instead?
> (This is legal in SAML V2.0, right?)
That's not what the protocol is trying to permit, though.
> In general, what are the uses of an empty assertion?
Nothing I can think of, and I would tend to think it wasn't really meant to
be valid. XSD doesn't have co-constraints, so you can't say "Subject is
required unless there are no statements..." or that kind of thing.
-- Scott
