Introduction

Understanding what cybercrime is and how cybercrimes can be committed only gives an investigator half the picture. Just as every police officer needs a good grasp of physical defensive tactics, the cybercrime investigator must be aware of the tactics that are commonly used to defend a network from criminal intrusion or attack. In this chapter, we discuss the basic concepts involved in computer and network security. This includes the importance of multilayered security and the components that make up a multilayered security plan. We also emphasize the need for investigators to talk the talk by learning computer security terminology.

We discuss physical security, the first (and often-overlooked) line of defense. We show you how network administrators keep workstations and servers secure and how a good security plan goes a step further to protect the network s routers, switches, hubs, and other connectivity devices, as well as the cable over which the signal travels (and from which it can be intercepted). We also look at special problems involved in physically securing portable computers and some innovative products that can be used to protect these computers and the data they contain.

Next, we delve into the fascinating and complex world of cryptography, the study of hidden writing. We look at encryption technologies and algorithms and the many ways in which encryption can be used to protect data stored on computers or traveling across the network. You learn about the purposes of encryption in the context of network security and how it can...