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Usable Cyber Trust Indicators

Researcher: Lorrie Cranor

Research Area: Privacy Protection

Cross Cutting Thrusts: Usable Privacy and Security


When systems rely on a "human in the loop" to carry out a security-critical function, cyber trust indicators are often employed to communicate when and how to perform that function. Cyber trust indicators typically serve as warnings or status indicators that communicate information, remind users of information previously communicated, and influence user behavior. They include a variety of security- and privacy-related symbols in the operating system status bar or browser chrome, pop-up alerts, security control panels, or symbols embedded in web content. However, a growing body of literature has found the effectiveness of many of these indicators to be rather disappointing. It is becoming increasingly apparent that humans are a major cause of computer security failures and that security warnings and other cyber trust indicators are doing little to prevent humans from making security errors. In some cases, it may be possible to redesign systems to minimize the need for humans to perform security-critical functions, thus reducing or eliminating the need for security warnings. However, in many cases it may be too expensive or difficult to automate security-critical tasks, and systems may need to rely on human judgment. In these cases, it is important to situate security indicators both spatially and temporally to maximize their effectiveness, and to design them to communicate clearly to users. The goal of this research is to systematically study the effectiveness of cyber trust indicators and develop approaches to making these indicators most effective and usable. We are currently focusing on security warning dialogs.