Trust in Computer Systems and the Cloud

CHAPTER 7The Importance of Time

As we have looked at our definition of trust and the corollaries associated with it, we have continually returned to the point that time is an important context to consider as part of a trust relationship. Sometimes the extent to which time is relevant is fairly obvious, such as in the case of the web transaction we examined at the end of the last chapter, where the length of the transaction, and the connection associated with it, determined the time context for most of the trust relationships. In this chapter, we will take a deeper look at trust and time in the context of computers and systems.

Decay of Trust

The very first examples of trust relationships that we examined in the book—my relationships to my brother and sister—made it clear that trust can decay. The example of my sister's not having worked as a dive instructor for a while was given as a reason for that trust relationship to decay: for my assurance in her to perform the correct actions to be reduced. To be clear, it is only in this context that the decay over time impacts in this particular way: I might (and would!) trust her to put me in the recovery position if I were rendered unconscious. While she might forget this skill over time, the rate of decay is different for this trust relationship, though they both relate to skills that could save my life—in the appropriate context.

How similar to these sorts of human trust relationship calculations (using the term calculations