More Than Skin Deep: Measuring Effects of the Underlying Model on Access-Control System Usability
In access-control systems, policy rules conflict when they prescribe different decisions (ALLOW or DENY) for the same access. The authors present the results of a user study that demonstrates the significant impact of conflict-resolution method on policy-authoring usability. In the study of 54 participants, varying the conflict-resolution method yielded statistically significant differences in accuracy in five of the six tasks the authors tested, including differences in accuracy rates of up to 78%. The results suggest that a conflict-resolution method favoring rules of smaller scope over rules of larger scope is more usable than the Microsoft Windows operating system's method of favoring deny rules over allow rules.