Chapter List

A Need for Security

Modern society and modern economies rely on infrastructures for communication, finance, energy distribution, and transportation. These infrastructures depend increasingly on networked information systems. Attacks against these systems can threaten the economical or even physical well-being of people and organizations. There is widespread interconnection of information systems via the Internet, which is becoming the world's largest public electronic marketplace, while being accessible to untrusted users. Attacks can be waged anonymously and from a safe distance. If the Internet is to provide the plat-form for commercial transactions, it is vital that sensitive information (like credit card numbers or cryptographic keys) is stored and transmitted securely.

Problems

Developing secure software systems correctly is difficult and error-prone. Many flaws and possible sources of misunderstanding have been found in protocol or system specifications, sometimes years after their publication or use. For example, the observations in [Low95] were made 17 years after the well-known Needham-Schroeder authentication protocol had been published in [NS78]. Many vulnerabilities in deployed security-critical systems have been exploited, sometimes leading to spectacular attacks. For example, as part of a 1997 exercise, an NSA hacker team demonstrated how to break into US Department of Defense computers and the US electric power grid system, among other things simulating a series of rolling power outages and 911 emergency telephone overloads in Washington, DC, and other cities [Sch99a]. While there are of course many more recent examples of security...