THERE ARE A MULTITUDE OF APPROACHES TO MAKING SECURITY USABLE AND USEFUL. Some approaches concentrate on the usability of the security information, mechanisms, and displays themselves. Some approaches concentrate on making as much security as possible disappear into the context of more task-directed functions, from the point of view of as many (types of) users as possible. Under the best circumstances, security and usability, along with performance, are considered and integrated in initial architectural and design discussions. As products evolve and mature, new challenges in these areas arise, and the solutions need to work well with existing, deployed code and data. The breadth of risks, threats, and features often generates a range of solutions that....