A Comparative Usability Study of Key Management in Secure Email

We conducted a user study that compares three secure email tools that share a common user interface and differ only by key management scheme: passwords, public key directory (PKD), and identity-based encryption (IBE). Our work is the first comparative (i.e., A/B) usability evaluation of three different key management schemes and utilizes a standard quantitative metric for cross-system comparisons. We also share qualitative feedback from participants that provides valuable insights into user attitudes regarding each key management approach and secure email generally. The study serves as a model for future secure email research with A/B studies, standard metrics, and the two-person study methodology.