1.6 What's Next
This book describes all aspects of security in computing. By studying it, you will become acquainted with computer security's major problem areas, the controls that are effective against them, and how current research is addressing the open problems.
To present security in a comprehensive way, this book is organized in four parts. The first part introduces encryption, an important tool on which many controls are based. That introduction presents encryption's goals, terminology, and use. You will be able to understand the role of encryption in addressing security needs without having to learn the intricate details of particular encryption methods. The second part contains material on the hardware and software components of computing systems. We describe the types of problems to which each is subject and the kinds of protection that can be implemented for each component. The third part of the book discusses factors outside the system's hardware, software, and data that can influence the system's security. In particular, this part contains a study of physical factors in security, as well as characteristics of the people who use the system. The book's final section is a more detailed study of encryption, for those readers who are interested in understanding the intricacies of encryption techniques and evaluating their effectiveness.
The remainder of this section presents the contents of these parts in more depth.
Chapter 2 presents the goals and terminology of encryption so that you will understand not only why data are scrambled but also the role of the scrambling in the larger context of protecting assets. This chapter provides you with knowledge of encryption sufficient for study of its use as part of other security tools and techniques.
Hardware and Software Security
Chapters 3 through 7 address the role of security in general programs, operating systems, database management systems, and networks. In particular, the security problems and features of programs are introduced in Chapter 3. Here, we look at viruses and other malicious code and ways to devise controls against them.
Operating systems are considered separately, in Chapter 4, because they play a major role in security and are fundamental to proper computer usage. While providing security features to protect one user from another, operating systems can at the same time introduce security vulnerabilities themselves. Chapter 5 focuses on a special type of operating system, called a trusted operating system, to study how to make certain data and functions accessible only to those who have the need or permission to view or handle them. This chapter is especially important for those developers who plan to design their own operating systems or modify functions in an existing operating system.
Database management systems are also specialized programs: they permit many users to share access to one common set of data. Because these systems are partially responsible for the confidentiality, integrity, and availability of the shared data, we look at database security in Chapter 6.
Chapter 7 contains material on security problems and solutions particular to computer networks and the communications media by which networked computers are connected. Network security has become very significant because of the rapid growth in use of networks, especially the Internet.
Human Controls in Security
The first two parts of this book form a progression from simple security applications and tools to complex security technology in multiuser, multicomputer systems. These technology-based security methods are rather sophisticated, and researchers continue to look to technology to assist in security assurance. However, most computer-based security breaches are caused by either human or environmental factors. Thus, Chapters 8 through 11 suggest alternative or supplemental approaches to computer security: Treat the causes (people and the environment) rather than the symptoms (attacks and vulnerabilities). We examine procedures that can be implemented in spite of, or in addition to, any controls built into hardware and software.
Chapter 8 addresses the administration of security. It begins with security planning and the particularly important role played by risk analysis. The chapter also explains physical security mechanisms that can be used to protect computing systems against human attacks or natural disasters. It explains why security policy is essential to security planning, illustrating the concepts with several examples from actual organizational policy documents. The chapter concludes with a discussion of disaster recovery: how to deal with the failure of other controls.
Chapter 9 looks at the economics of cybersecurity. In any organization, security is just one of many competing needs. Security will never be the "long pole in the tent," getting a disproportionately large share of resources; too often, unfortunately, it ends up being the short pole, suffering from inattention. In Chapter 9 we describe the economic case for cybersecurity: how to justify spending on security (which often means not spending on facilities or benefits or marketing) and how to demonstrate that investing in security has paid off.
In Chapter 10 we consider privacy, which is a different part of the human side of computer security. As more data are collected about more people, two concerns arise: First, who owns or controls personal data, and what are acceptable uses of that data, and second, how are personal data protected against loss or inappropriate disclosure? As data collection and analysis systems grow and new ones are developed, now is the right time to ensure that appropriate security controls protect these valuable kinds of data.
Chapter 11 considers the use of law and ethics to control malicious behavior. Although computer law is a relatively new field, it is evolving rapidly and is an important tool in the defense of computing systems. We look at how ethical systems may address some situations where the law is ineffective, inappropriate, or inadequately defined.
Chapter 12 builds on the simple encryption methods and terminology presented in Chapter 2. It progresses from theoretical encryption algorithms to current standard practices in the field. We study what makes a cryptosystem secure enough for commercial use; for protecting government data; or for securing your own private, personal information.
Throughout the book, we raise issues related to the important problems in computer security today. When the solution is known, we describe it or at least give you pointers to a fuller description of the solution. At the same time, we discuss work in progress so that you can watch the media and the literature for significant achievements in improving computer security.
It is important to remember that computer security is a relatively new field that is gaining prominence as computing itself becomes pervasive. The speed of new development in computing far outpaces capabilities in computer security. It sometimes seems as if each advance in computing brings with it new security problems. In a sense, this is true. However, there is reason to be optimistic. The fundamental work in security provides tools (such as encryption and operating system features) that form the basis of controls for these new problems as the problems arise. Part of the excitement of computer security is that there are always new challenges to address.