Searching for privacy: Design and implementation of a P3P-enabled search engine

Although the number of online privacy policies is increasing, it remains difficult for Internet users to understand them, let alone to compare policies across sites or identify sites with the best privacy practices. The World Wide Web Consortium (W3C) developed the Platform for Privacy Preferences (P3P1.0) specification to provide a standard computer-readable format for privacy policies. This standard enables web browsers and other user agents to interpret privacy policies on behalf of their users. This paper introduces our prototype P3P-enabled Privacy Bird Search engine. Users of this search service are given visual indicators of the privacy policies at sites included in query results. Our system acts as a front end to a general search engine by evaluating the P3P policies associated with search results against a user's privacy preference settings. To improve system performance we cache unexpired P3P policy information (including information about the absence of P3P policies) for thousands of the most popular sites as well as for sites that have been returned in previous search results. We discuss the system architecture and its implementation, and consider the work necessary to evolve our prototype into a fully functional and efficient service.