A brick wall, a locked door, and a bandit: A physical security metaphor for firewall warnings

We used an iterative process to design firewall warnings in which the functionality of a personal firewall is visualized based on a physical security metaphor. We performed a study to determine the degree to which our proposed warnings are understandable for users, and the degree to which they convey the risks and encourage safe behavior as compared to text warnings based on those from a popular personal firewall. The evaluation results show that our warnings facilitate the comprehension of warning information, better communicate the risk, and increase the likelihood of safe behavior. Moreover, they provide participants with a better understanding of both the functionality of a personal firewall and the consequences of their actions.