1.1 Introduction

The word trust means many different things to different people and in different contexts. Like the word security, it has become so overused that it is almost meaningless unless a definition is provided. This is certainly the case for the term trusted computing , and so one thing that we try to do in this chapter is define what trust means in this particular context. This theme is returned to in many of the other chapters in this book.

So what does trust mean for the purposes of this book? Well, perhaps the simplest definition would be that trusted computing refers to a computer system for which an entity has some level of assurance that (part or all of) the computer system is behaving as expected. The entity may be any one of various things, including the human user of the PC or a program running on a remote machine. The degree of coverage of this assurance, that is, whether it covers all aspects of the system or just some part, and the nature of the entity to which assurance is provided, vary depending on the system and the environment within which it is used.

Bodies such as the Trusted Computing Group standardise specific functionality to be incorporated into end systems which are known as trusted platforms . Depending on how the specified functionality is implemented, such a platform is then able to provide a degree of assurance about some aspect of its operation.

Section 1.2 and...