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- The entity attribute and/or the IAQ has to be dated or versioned to indicate exactly what IAP is referred to.
SP behavior
Ideally SPs that require a particular assurance level will initiate the assurance flow by including the desired IAQ in the SAML AuthnRequest element.
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SPs will rely on local policy to decide how to handle incoming IAQs. For example if the SP requires InCommon Bronze but receives InCommon Silver, that should be is probably acceptable.
SP Policy Use Cases
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- Some SPs may not be able to use the AuthnRequest mechanism due to software or other limitations. Are they simply out of luck?
- One option may be to use additional software to generate requests on behalf of the broken SP, although this isn't guaranteed to work with all SPs. Otherwise, such SPs will be forced to rely on OOB configuration of IdPs.
- How is the AuthnRequest configured using the Shib SP? The simpleSAMLphp SP?
- Shibboleth SPs can rely on the authnContextClassRef setting to control the value requested when particular resources are accessed. To include multiple values in a request, the AuthnRequest "template" mechanism described in the SessionInitiator documentation can be used.
- Boarding process: Since an IAQ in metadata makes a statement about certification (not live service), how does an SP determine that an IdP supports assurance operationally (ala attribute support)? One approach is to include
<saml:Attribute>elements in IdP metadata. Other approaches?- There is no metadata support for this requirement. SPs should be able to handle errors returned by IdPs that indicate the requested assurance level was not supported. The federation should help establish guidelines for describing such errors, perhaps with a FAQ page that could be linked in.
- Does the Shib SP software support the metadata check? Does the simpleSAMLphp SP?
- The Shibboleth SP can extract and make available the entity attribute value in a variable along with user attributes, and use the variable in authorization policy. This is described under "metadata attribute extraction".
- What matching rules are recommended, or acceptable?
- How is an SP supposed to "know" that Silver is acceptable in lieu of Bronze? Is there a role for InCommon to provide "advice"?
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