Christina P. Katsini

Influences of Users' Cognitive Strategies on Graphical Password Composition

Recent research reveals interaction effects among human cognitive processing factors, interaction device types and user authentication schemes towards security of user created graphical keys. Aiming to investigate how different visual behaviors of individuals with varying cognitive strategies affect the security aspects of graphical user authentication (GUA) across device types, this paper reports preliminary results of a user study (N=51) on graphical password composition using a recognition-based GUA scheme. Results reveal differences on key strength and complexity, as well as on gaze-based entropies between users with different cognitive strategies, which can be used for the design of user-adaptive GUA schemes.

Security and Usability in Knowledge-based User Authentication: A Review

This paper presents a comprehensive review of state-of-the-art research works in knowledge-based user authentication, covering the security and usability aspects of the most prominent user authentication schemes; text-, pin- and graphical-based. From the security perspective, we analyze current threats from a user and service provider perspective. Furthermore, based on current practices in authentication policies, we summarize and discuss their security strengths based on widely applied security metrics. From the usability point of view, we present and discuss the usability of each authentication scheme in regards with task performance and user experience. The analysis reveals that although a plethora of alternative user authentication schemes have been proposed in the literature and users interact differently with the various alternatives, online service providers do not yet adopt alternatives to text-based solutions. We further discuss and identify areas for further research and improved methodology with the aim to drive this research towards the design of sustainable, secure and usable authentication approaches.

Effects of Human Cognitive Differences on Interaction and Visual Behavior in Graphical User Authentication

This paper discusses two user studies to investigate whether human cognitive differences affect user interaction and visual behavior within recognition-based graphical authentication tasks. In order to increase external validity, we conducted the studies with separate user samples. In the first study (N = 82) which embraced a longitudinal and ecological valid interaction scenario, we examined whether field dependence-independence (FD-I) differences have an effect on their login performance. During the second study (N = 51) which embraced an in-lab eye tracking setup, we investigated whether FD-I differences of participants are reflected on their visual behavior during graphical key creation. Analysis of results revealed interaction effects of users’ FD-I differences which indicate that such human cognitive differences should be considered as additional human design factors in graphical user authentication research.

Effects of Image-Based Rendering and Reconstruction on Game Developers Efficiency, Game Performance, and Gaming Experience

Image-based rendering and reconstruction (IBR) approaches minimize time and costs to develop video-game assets, aiming to assist small game studios and indie game developers survive in the competitive video-game industry. To further investigate the interplay of IBR on developers’ efficiency, game performance, and players’ gaming experience we conducted two evaluation studies: a comparative, ecologically valid study with professional game developers who created games with and without an IBR-based game development pipeline, and a user study, based on eye-tracking and A/B testing, with gamers who played the developed games. The analysis of the results indicates that IBR tools provide a credible solution for creating low cost video game assets in short time, sacrificing game performance though. From a player’s perspective, we note that the IBR approach influenced players’ preference and gaming experience within contexts of varying levels of player’s visual intersections related to the IBR-created game assets.

Towards a Cognition-Centered Personalization Framework for Cultural-Heritage Content

Comprehension of visual content is linked with the visitors experience within cultural heritage contexts. Considering the diversity of visitors towards human cognition, in this paper, we aim to investigate whether cognitive characteristics are associated with the comprehension of cultural-heritage visual content. We conducted a small-scale eye-tracking study in which people with different visual working memory capacity participated in a gallery tour and then they were assessed towards exhibit comprehension. The analysis of the results revealed that people with low visual working memory faced difficulties in comprehending the content of the gallery paintings. In this respect, we propose a cognition-centered cultural heritage framework, aiming to provide personalized experiences to visitors and help them improve the content comprehension.

Does image grid visualization affect password strength and creation time in graphical authentication

Nowadays, technological advances introduce new visualization and user interaction possibilities. Focusing on the user authentication domain, graphical passwords are considered a better fit for interaction environments which lack a physical keyboard. Nonetheless, the current graphical user authentication schemes are deployed in conventional layouts, which introduce security vulnerabilities associated with the strength of the user selected passwords. Aiming to investigate the effectiveness of advanced visualization layouts in selecting stronger passwords, this paper reports a between-subject study, comparing two different design layouts a two-dimensional and a three dimensional. Results provide evidence that advanced visualization techniques provide a more suitable framework for deploying graphical user authentication schemes and underpin the need for considering such techniques for providing assistive and/or adaptive mechanisms to users aiming to assist them to create stronger graphical passwords.