Authorization and Certificates: Are We Pushing When We Should Be Pulling?

Certificates have long been used to bind authorization information to an identity or public key. Essentially there are two ways in which a verifying authority (reference monitor) can obtain the information (from a certificate) that is required to make an access control decision: the requesting entity provides the privilege attributes to the verifying authority – a ‘push’ model; or the verifying authority obtains the privilege attributes from a trusted repository – a ‘pull’ model. In this paper we argue that a push model, which is used by most certificate-based authorization mechanisms, is inferior to a pull model, and present an architecture based on the pull model.