Graphical User Authentication: A Comparative Evaluation of Composite Scene Authentication vs. Three Competing Graphical Passcode Systems

Abstract

Previous studies (Johnson & Werner, 2006; 2007) have shown that Composite Scene Authentication (CSA) passcodes are more memorable than alphanumeric passwords over extended retention intervals. This study evaluated the memorability of six types of graphical passcodes of varying complexity (including three variants of CSA passcodes) over thirty-minute and one-week retention intervals. The graphical passcodes were compared to one another, as well as to an alphanumeric password of equivalent bit length. A strong overall advantage in information retained was found for graphical passcodes (M = 92.83%) compared to alphanumeric passwords (M = 75.47%). In addition, CSA passcodes were remembered better (M = 97.1 %) than other graphical passcodes (M = 88.56%). An even larger difference was observed for percent successful logins for CSA passcodes (M = 84.23%) compared to other graphical passcodes (M= 56.39%) after the one-week retention interval. The variable bit lengths of the passcodes did not affect percent information retained.