Understanding the Design Space of Embodied Passwords based on Muscle Memory

ABSTRACT Passwords have become a ubiquitous part of our everyday lives, needed for every web-service and system. However, it is challenging to create safe and diverse alphanumeric passwords, and to recall them, imposing a cognitive burden on the user. Through consecutive experiments, we explored the movement space, affordances and interaction, and memorability of a tangible, handheld, embodied password. In this context, we found that: (1) a movement space of 200 mm × 200 mm is preferred; (2) each context has a perceived level of safety, which—together with the affordances and link to familiarity—influences how the password is performed. Furthermore, the artefact’s dimensions should be balanced within the design itself, with the user, and the context, but there is a trade-off between the perceived safety and ergonomics; and (3) the designed embodied passwords can be recalled for at least a week, with participants creating unique passwords which were reproduced consistently.