The Science and Technology of Privacy Protection: Appendix L of "Protecting Individual Privacy in the Struggle Against Terrorists"

To the extent that there is a tension between counterterrorism efforts and protection of citizens’ privacy, it is useful to understand how it may be possible to design counterterrorism information systems to minimize their impact on privacy. This appendix considers privacy protection from two complementary perspectives—privacy protection that is built into the analytical techniques themselves and privacy protection that can be engineered into an operational system. The appendix concludes with a brief illustration of how government statistical agencies have approached confidential data collection and analysis over the years. A number of techniques described here have been proposed for use in protecting privacy; none would be a panacea, and several have important weaknesses that are not well understood and that are discussed and illustrated.