Trust in Computer Systems and the Cloud

CHAPTER 8Systems and Trust

We have spent a fair amount of time talking about components and how we need to consider composites of components as systems, looking in detail at systems in Chapter 5. In this chapter, we will concentrate on systems and their position in trust relationships in terms of both the benefits they bring and also the dangers or complications they can introduce. First, however, we will consider briefly what a system might consist of: what are its constituent parts?

System Components

The main focus of this chapter is fairly small systems, though it will become clear pretty quickly that lack of size does not necessarily equate to lack of complexity. Before we move on to such considerations, however, we need to spend a little time thinking about larger systems and what their parts and components might be consist of. In Chapter 3, we defined a system as

a set of components—for example, hardware, software, firmware, data, human users—that can be considered a single entity for the purposes of one or more specific architectural views or abstractions.

Given our focus—which is on the realm of computer-to-computer trust relationships—we have generally been concentrating on hardware and software (with firmware sometimes being considered separately) in automated configurations; but the definition of a system is wider than that, and we should also examine systems driven by user input. In doing so, we can note that the definition specifically includes humans (sometimes ...