Title: Subject in the AuthRequest.
In the AuthRequest
there is a <saml:Subject> tag where the requestor can specify the
subject of the resulting assertion.
Can anyone please give an example/use case ? I
thought it was the IDP during AuthReq to determine the Subject.
If the SP knows the subject (I'm assuming
that somehow the subject had to be previously authenticated and an assertion
generated) wouldn't it perform an AssertionQuery kind of request instead
?
AuthnRequest with a subject would typically be used if
you wanted to initiate an SSO session with a specific user. This may be
because you are running into the end of a session validity period on an existing
assertion (and want to renew for the same user) or you want to change the
subject that was previously authenticated in the current
"session".
AuthnQuery is how you query for an *existing*
assertion, not create a new assertion for a new or extended SSO
session.
Subject can contain subject confirmation data to
indicate how and by whom the resulting assertions can be confirmed.
In the case of holder of key for example the SP
would include the Key the SP owns to confirm the subject.
Shouldn't the IDP verify this key?
This is typically used in non-SSO cases where the requestor
is asking for an assertion for a different relying party AND saying that
such assertion(s) should require the confirmation of the specified key in
order to be used.
The IdP needs to consider whether or not the requestor
is allowed to specify its own key, but typically doesn't need to verify the
key.
Conor