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The Service Provider Assurance policy requirements can be expressed in several use cases. Below is a list of the tested cases requested by SPs intending to request qualifiers in 2012.

UC0: SP Requires Silver

The SP requires InCommon Silver LOA.

The SP includes http://id.incommon.org/assurance/silver in the SAML AuthnRequest RequestedAuthnContext element. It accepts assertions that contain http://id.incommon.org/assurance/silver in the AuthnContext from IdPs with http://id.incommon.org/assurance/silver in InCommon metadata, that is, the SP explicitly verifies that the assertion contains http://id.incommon.org/assurance/silver in the AuthnContext and that InCommon metadata contains http://id.incommon.org/assurance/silver for the issuing IdP.

The SP may choose to short-circuit a request to an IdP with no http://id.incommon.org/assurance/silver in InCommon metadata or provide a discovery interface that lists only IdPs with http://id.incommon.org/assurance/silver in InCommon metadata.

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Commentary:

The As usual, the SP should intelligently handle errors. In particular, the SP should be prepared to handle the case that not all users at a particular IdP may be eligible for Silver LOA ( for example, users not vetted at the Silver LOA), so even if the IdP is tagged with http://id.incommon.org/assurance/silver in InCommon metadata, authentication for some users may result in a "FatalProfileException".

Examples:

an "AuthnFailed" response.

As an optimization, the SP may avoid issuing requests to IdPs that are not certified Silver, since these requests would always be rejected later anyway. The SP may locally block ("short-circuit") requests of this type. The SP may provide a local discovery interface that lists only IdPs with http://id.incommon.org/assurance/silver in metadata to constrain users to only choose Silver certified IdPs. Errors must be anticipated in any event.

Examples:

• NSC Meteor Access for Financial AIdNIH SPs?

UC1: SP Requires Bronze

The SP requires InCommon Bronze LOA (or higher).

The SP includes http://id.incommon.org/assurance/silverbronze and http://id.incommon.org/assurance/bronzesilver in the SAML AuthnRequest RequestedAuthnContext element. It The SP accepts either:

• Assertions assertions that contain http://id.incommon.org/assurance/silverbronze in the AuthnContext from IdPs with http://id.incommon.org/assurance/silverbronze in InCommon metadata, orAssertions
• assertions that contain http://id.incommon.org/assurance/bronzesilver in the AuthnContext from IdPs with http://id.incommon.org/assurance/bronzesilver in InCommon metadata.

Commentary:

As usual, the SP should intelligently handle errors. In particular, the SP should be prepared to handle the case that not all users at a particular IdP may be eligible for Silver or Bronze LOA (for example, users not vetted at the Silver LOA or passwords too weak for Bronze LOA)Bronze or Silver, so even if the IdP is tagged with http://id.incommon.org/assurance/silver and/or http://id.incommon.org/assurance/bronze in InCommon metadata, authentication for some users may result in a "FatalProfileException"an "AuthnFailed" response.

As an optimization, the SP may avoid issuing requests to IdPs that are not certified Bronze, since these requests would always be rejected later anyway. The SP may locally block ("short-circuit") requests of this type. The SP may provide a local discovery interface that lists only IdPs with http://id.incommon.org/assurance/bronze in metadata to constrain users to only choose Bronze certified IdPs. Errors must be anticipated in any event.

Note:

Since Bronze is a subset of Silver, IdPs with http://id.incommon.org/assurance/silver in metadata will necessarily have http://id.incommon.org/assurance/bronze in metadata as well. Thus the SP may focus on Bronze to build its discovery interface.

Examples:

• The InCommon Federation Manager (FM)
• The InCommon Certificate Manager (CM)

The FM requires Bronze password credentials for delegated administrators. Also, both the FM and the CM recognize require Bronze password credentials as the first factor of a two-factor authentication. The InCommon Operations Identity Provider is authoritative for the second "what you have" factor.

...

The SP must operate in a world where not all IdPs can yet provide Silver LOA assertions, and Silver-capable IdPs can't provide Silver assertions for all users/circumstances. In cases where lower LOA assertions are used, the SP restricts access/functionality and/or implements other compensating controls. The SP wants to get Silver assertions whenever possible. The SP can determine which IdPs are Silver-capable from metadata.For IdPs that are not Silver-capable according to metadata, the SP does not include an IAQ in the SAML AuthnRequest element, and the SP applies compensating controls for the resulting lower LOA.

For IdPs that are Silver-capable according to metadata, the SP includes http://id.incommon.org/assurance/silver and urn:oasis:names:tc:SAML:2.0:ac:classes:unspecified in the SAML AuthnRequest element. It accepts at Silver LOA assertions that contain RequestedAuthnContext element. If the IdP returns an assertion containing http://id.incommon.org/assurance/silver in the AuthnContext from IdPs with , the SP checks that the IdP has http://id.incommon.org/assurance/silver in their InCommon metadata. The SP applies compensating controls for all other assertions (considered to be lower LOA). The SP handles errors from the IdP (i.e., opensaml::FatalProfileException) by making a new request without a AuthnRequest element, in case the IdP is not able to handle the AuthnRequest element, resulting in a lower LOA authentication. Ideally the user will not be prompted to authenticate a second time for this second request by the SP, i.e., the IdP has set a cookie in the user's browser.Alternatively, the SP may include only http://id.incommon.org/assurance/silver in the SAML AuthnRequest element, and if the SP returns an error (i.e., opensaml::FatalProfileException)its InCommon metadata, and if the check passes, the SP considers the authentication to be at the Silver level. Alternatively, if the IdP returns an "AuthnFailed" response, possibly indicating the particular user is not Silver qualified, the SP makes a new request without a AuthnRequest RequestedAuthnContext element, resulting in for a lower LOA authentication. Again, ideally Ideally the user will not be prompted to authenticate a second time for this second request by the SP, i.e., the IdP has set a cookie in the user's browser.

Examples:

• CILogon

UC3: SP Prefers Bronze

...As an optimization, the SP may choose to look in InCommon metadata and not include a SAML RequestedAuthnContext element in requests to IdPs that are not Silver accredited.

Examples:

• Research.GovCILogon