Participants from recent secure email user studies have expressed a need to use secure email tools only a few times a year. At the same time, Internet users are expressing concerns over the permanence of personal information on the Internet. Support for short-lived keys has the potential to address both of these problems. However, the short-lived keys usability and security space is underdeveloped and unexplored. In this thesis, we present an exploration of the short-lived keys usability and security design space. We implement both a short-lived keys and a long-term keys secure email prototype. With these two prototypes, we conduct a within-subjects user study. Results from our study show that participants believe the short-lived keys prototype is more secure and more trusted. Participants also provide feedback on what they want in a system supporting short-lived keys. They also discuss how concerned they are about the permanence of their information on the Internet and on their devices.