Limiting Exposure by Hiding the Action

This chapter considers the second leaf in the privacy tree, examining PETs that limit exposure by hiding the user’s actions. As examples of this category, the following PETs are described: transport layer security; network layer security (IPsec in transport mode); and private information retrieval. As with the previous chapter, for each of these examples, the original scheme is given, enhancements made over the years are presented, and strengths and limitations of the technology are discussed.