1 Towards Usefully Secure Email Chris Masone and Sean Smith Department of Computer Science Dartmouth College cmasone,
[email protected] Abstract— When users’ mental models don’t match the bring human mental models and the behavior of systems way the underlying systems work, problems can arise. into closer alignment, thus avoiding these problems, we For human-based security systems to be effective, we believe software must be designed to explicitly leverage believe that is important to identify the tasks involved at which humans excel (and at which computers do not), and the people who use it; lay out the goals of the system, then design the system accordingly. To demonstrate this identify the tasks involved at which humans excel (and principle, we are building Attribute-Based, Usefully Secure at which computers do not), and then design the system Email (ABUSE), a system that leverages users by enabling accordingly. them to build a decentralized, non-hierarchical PKI to express their trust relationships with each other, and then To demonstrate this design principle, we have chosen to to use this PKI to manage their trust in people with whom build Attribute-Based, Usefully Secure Email (ABUSE), they correspond via secure email. Our design puts humans into the system—to do things that humans are good at a system that leverages users by enabling them to build but machines are not—at both the creation of credentials a decentralized, non-hierarchical PKI to express their as well as the interpretation of credentials. In this paper, trust relationships with each other, and then use this we discuss why secure email is an interesting proving PKI to manage their trust in people with whom they ground for our design ideas, set out the architecture of correspond via secure email.