Preface to the Third Edition

Every day, the news media give more and more visibility to the effects of computer security on our daily lives. For example, on a single day in June 2002, the Washington Post included three important articles about security. On the front page, one article described the possibility that a terrorist group was plotting to ”and actually could ”invade computer systems and destroy huge dams, disable the power grid, or wreak havoc with the air traffic control system. A second article, also on the front page, considered the potential loss of personal privacy as governments and commercial establishments begin to combine and correlate data in computer- maintained databases. Further back, a third article discussed yet another software flaw that could have widespread effect. Thus, computer security is no longer relegated to esoteric discussions of what might happen; it is instead a hot news topic, prominently featured in newspapers, magazines, radio talk shows, and documentary television programs. The audience is no longer just the technical community; it is ordinary people, who feel the effects of pervasive computing.

In just a few years the world's public has learned the terms "virus," "worm," and "Trojan horse" and now appreciates the concepts of "unauthorized access," " sabotage ," and "denial of service." During this same time, the number of computer users has increased dramatically; with those new users have come new uses: electronic stock trading, sharing of medical records, and remote control of sensitive equipment, to name just three. It should be no surprise that threats to security in computing have increased along with the users and uses.