Improving the Design and Usability of Password Creation Systems

The aim of this research is to inform the design and usability of password creation systems (PCSs) and their supporting features so they can better support users when creating passwords. PCSs are a particular class of an interactive system that allow users to create passwords and which may offer supporting features to help users that process. The supporting features include statements of password policy, password creation suggestions, and password strength indicators. The thesis addresses this aim at the user interface level by providing knowledge about how users react to a range of aspects of the supporting features in PCSs and by providing a set of usability heuristics and guidelines to support the evaluation and development of existing PCSs. There were three phases of research, each consisting of studies that provided insights for the next one. The first phase focused on understanding current practices in PCSs and their effects on users. The outcome of this phase revealed a high number of usability problems including lack of supporting features, design presentation flaws, and ambiguity in password instructions. The second phase investigated the effects of different design aspects in PCSs. The findings showed that different design aspects of PCSs had a significant effect on the usability and password strength in different ways. The third phase proposed a set of usability heuristics and guidelines specifically for the evaluation and design of PCSs. The heuristics were evaluated by usability professionals and were perceived to be easy to understand, clear, and useful. A mixture of qualitative and quantitative methods was used to answer the research questions. The findings suggest that PCSs can effectively support users in creating passwords by addressing four key factors: (1) provision of supporting features, (2) user instructions for creating passwords, (3) timing of presentation for presenting statements of policy and creation suggestions, and (4) media and colour scheme for designing strength indicators