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The identity assurance of a given interaction of user, IdP and SP is dependent on many factors. However, in the interest of simplicity of operation, it seems desirable for an IdP to assert that a given interaction, taking everything into consideration, fits a particular identity assurance profile. NIH SPs, for example, would like simple assertions of this kind. This essentially means that an IdP would want to make sure that all aspects of a given user's identity proofing, credentials and attribute reliability fit the "bronze" or "silver" profile