Usable security: authentication of choice in mobile devices

When interacting with an application, users expect to complete the desired tasks securely with minimal interference of actions required to ensure security and privacy. Previous research confirmed that there is a tradeoff between the security and usability of an application. Although numerous user studies examined various authentication methods such as alphanumeric password, graphical password, and biometrics, very limited research investigated users’ performance and perception when they are allowed to choose the authentication method(s) for a specific application. In this dissertation, we investigated how users interact with and perceive the ‘authentication of choice’ method when using a mobile device through two studies, one focusing on initial interaction, the other examining the interaction during the period of one week. The participants completed both studies online that compared three different authentication designs: alphanumeric username and password, one-factor authentication of choice, and two-factor authentication of choice. The result of the study confirms the tradeoff between security and usability in the design of authentication mechanisms. The result also indicates that the ‘authentication of choice’ approach has the potential to offer a solution that provides the desired balance between usability and security.