Trust in Computer Systems and the Cloud

CHAPTER 1Why Trust?

I trust my brother and my sister with my life. My brother is a doctor, and my sister trained as a diving instructor, so I wouldn't necessarily trust my sister to provide emergency medical aid or my brother to service my scuba gear. I should actually be even more explicit because there are times when I would trust my sister in the context of emergency medical aid: I'm sure she'd be more than capable of performing CPR, for example. On the other hand, my brother is a paediatrician, not a surgeon, so I'd not be very confident about allowing him to perform an appendectomy on me. To go further, my sister has not worked as a diving instructor for several years now, so I might consider whether my trust in her abilities should be impacted by that.

This is not a book about human relationships or trust between humans, but about trust in computer systems. In order to understand what that means—or even can mean—however, we need to understand what we mean by trust. Trust is a word that arises out of human interactions and human relationships. Words are tricky. Words can mean different things to different people in different contexts.

The classic example of words meaning different things depending on context is the names of colours—the light frequencies included in the colours I identify as mauve, beige, and ultramarine are very likely different to yours—but there are other examples that are equally or more extreme. If I discuss “scheduling” with an events coordinator, ...