ALTHOUGH A RELIABLE, USABLE AUTHENTICATION METHOD IS ESSENTIAL, it is far from the only human interface concern. After a user signs in to a system, the system has to carry out the user’s wishes correctly in order to be considered secure. The question of secure interaction design, addressed in this and the other chapters in this part of the book, is:
To give you a sense of how important it is to look beyond authentication, consider some of today’s most serious security problems. Viruses are a leading contender, with email viruses making up a large part. Spyware is growing into a nightmare for home users and IT staff. Identity theft is becoming widespread, perpetrated in part through “phishing” scams in which forged email messages entice people to give away private information. None of these problems is caused by defeating a login mechanism. They would be better described as failures of computers to behave as their users expect.
This chapter suggests some guidelines for designing and evaluating usable secure software and proposes two strategies for getting security and usability to work in harmony: security by designation and user-assigned identifiers. I’ll begin by providing a little background for our discussion, then present the guidelines and strategies, and finally look at real design problems to show how these strategies can be applied in practice.
This section introduces the topic ...