, Nathan Malkin , Ganesh Iyer , Serge Egelman , and David Wagner Tor ’ s Usability for Censorship Circumvention

Tor has grown beyond its original purpose as an anonymity tool and has become a widely-used cen­ sorship circumvention tool. This is the first study to ex­ amine Tor’s usability in this role. We evaluate, design, and test the Tor configuration interface by placing users in simulated censorship environments, instructing them to use Tor to circumvent censorship, and measuring their interactions with the interface. A 16-participant qualitative user study identifies common user struggles while circumventing censorship. We use the results as feedback to redesign the configuration interface. A 114­ participant quantitative user study tests the impact of our changes. We find that our changes result in a signif­ icant reduction in the time spent configuring a connec­ tions. We conclude with recommendations for changes to the current interface as well as alternative approaches to bootstrapping a connection to Tor.