Shoulder surfing susceptibility of bend passwords.

The emergence of flexible displays provides us with an opportunity to explore new forms of user authentication on mobile devices. In prior work, we developed an authentication scheme utilizing bend interaction on flexible displays. A common concern among users was that this scheme may be susceptible to shoulder surfing attacks. In this paper, we evaluate the susceptibility of our scheme to such observation. We found that bend passwords are extremely difficult to observe and replicate, with only one participant correctly guessing a single password. This contradicts users' initial impressions and suggests that bend passwords are secure against shoulder-surfing.