A small number of rules or laws can generate systems of surprising complexity… The rules or laws generate the complexity and the ever changing flux of patterns that follows leads to perpetual novelty and emergence. –John Holland
The problem of providing private communication over a public communication medium has always been considered important, since privacy of communication can be considered as a basic necessity of every user. With the advent of the Internet and the World Wide Web, it has become even more important to provide private communication. The essential security problem could be summarized as consisting of the following: How do peers such as Bob and Alice authenticate each other over the Internet, how do mutually authenticated users establish means for pursuing private communication, and how is communication between mutually trusting users protected against tampering and eavesdropping? As one could imagine, each of these is a vast problem on its own, addressing such crucial topics as trust, authorization, and confidentiality. In this chapter, we will briefly review the mechanisms used for supporting security for IP communication.
Providing security for communication over the Internet is also crucial for enabling such important applications as e-commerce, including banking, payments, purchasing, buying and selling in e-market places ...