Evaluating the effect of tolerance on click-draw based graphical password scheme

Abstract

To enhance graphical passwords, we have developed a system of click-draw based graphical password scheme (named CD-GPS) that combined current graphical password techniques and evaluated its performance with human users. In real settings, we identify that the effect of tolerance is a key factor affecting the usability of our scheme, however, we have not explored its specific effect in our previous work. In this paper, we therefore conduct a user study to investigate the effect of tolerance on creating and confirming the click-draw based graphical passwords. In particular, we conduct two experiments with totally 60 participants in the user study. The results show that accurate memory and reproduction for the CD-GPS scheme can be significantly reduced when the tolerance is greatly decreased (e.g., 12 x 12 pixels). In the end, we further discuss how to select an appropriate tolerance for the scheme of CD-GPS in real deployment. © 2012 Springer-Verlag.