Implementing P3P using database technology

Platform for Privacy Preferences (P3P) is the most significant effort currently underway to enable web users to gain control over their private information. P3P provides mechanisms for web site owners to express their privacy policies in a standard format that a user can programmatically check against her privacy preferences to decide whether to release her data to the web site. We discuss architectural alternatives for implementing P3P and present a server-centric implementation that reuses database querying technology, as opposed to the prevailing client-centric implementations based on specialized engines. Not only does the proposed implementation have qualitative advantages, our experiments indicate that it performs significantly better than the sole public-domain client-centric implementation and that the latency introduced by preference matching is small enough for real-world deployments of P3P.