Balancing Security and Usability in Encrypted Email

Abstract

End-to-end encryption is the best way to protect digital messages. Historically, end-to-end encryption has been difficult for people to use, but recent tools have made it more broadly accessible, largely by employing key-directory services. These services sacrifice some security properties for convenience. A 52-person user study found that participants could learn to understand properties of different encryption models and make coherent assessments about when different trade offs might be appropriate. Participants recognized that a less convenient key exchange model was more secure overall, but considered the key-directory approach to have security sufficient for most everyday purposes.