A global credential such as a public key and certificate in a public key infrastructure can be used to establish technical trust. A directory or distributed database such as the Domain Name System is used by the RP to discover the endpoint to contact for a given NAI. Either the database or certificates can provide a place to store information about rules determination and naming constraints. Provided that no intermediates are required (or appear to be required) and that the RP and IdP are sufficient to enforce and determine rules, rules determination is reasonably simple. However, applying certain rules is likely to be quite complex. For example, if multiple sets of rules are possible between an IdP and RP, confirming that the correct set is used may be difficult. This is particularly true if intermediates are involved in making the decision. Also, to the extent that directory information needs to be trusted, rules determination may be more complex.