Biblio

Users often need to authenticate at situated displays in order to, for example, make purchases, access sensitive information, or confirm an identity. However, the exposure of interactions in public spaces introduces a large attack surface (e.g., observation, smudge or thermal attacks). A plethora of authentication models and input modalities that aim at disguising users' input has been presented in the past. However, a comprehensive analysis on the requirements for secure and usable authentication on public displays is still missing. This work presents 13 design considerations suitable to inform practitioners and researchers during the development process of authentication systems for situated displays in public spaces. It draws on a comprehensive analysis of prior literature and subsequent discussion with five experts in the fields of pervasive displays, human-computer-interaction and usable security.

We explore the presentation technique of visual abstraction as a form of mediation to manage content generated by the public in order to maintain a respectful discourse. We identify technological and social mediation as two dimensions within the space of content mediation, and discuss different solutions based on related work in public interactive displays and art installations. We further discuss a novel approach to technological mediation by describing our interactive artwork Objective Meaning - an installation that invites the audience to express themselves through anonymous text messages. The design of this system mediates discourse by visually abstracting the presentation of messages on a display by breaking messages apart into decontextualized words. We briefly discuss the public response during a one-month deployment of the installation in a library setting.