Where Security Began

Abstract

This chapter will briefly introduce important security concepts and terminology. It will also briefly look at the history of security along with the history of the side channel. The security concepts are discussed with respect to Alice and Bob to be consistent with the field of cryptography; however, throughout the remainder of the book we will assume that Alice and Bob can in fact be embedded devices.

The four main security concepts used today are as follows: Confidentiality, integrity, authentication, and nonrepudiation.

We will discuss these concepts using the communication of messages between point A and point B or specifically communications between Alice and Bob on the channel. This will maintain consistency with many other cryptographic texts that use Alice and Bob. The channel, shown in Fig. 1.1a, is a very general concept and could represent a wire (for communication over a wired network) or electromagnetic waves (for wireless communications using cell phones). Security is designed for this channel with Eve in mind. Eve is named after the eavesdropper. However, she is in general an attacker or adversary. As shown in Fig. 1.1b Eve can eavesdrop to see all data on the channel. In Fig. 1.1c Eve can intercept data on the channel, modify it, and send it on to the destination. Finally in Fig. 1.1d Eve can intercept messages and masquerade as Bob without Bob receiving any of his intended messages. Of course, depending upon specifics of the channel some or none of these attacks may be possible. Additionally there may be other attacks such as Eve initiating communication on the channel, or Eve masquerading as both Alice and Bob, in order to attack communications between Alice and Bob, etc.