Conscript Your Friends into Larger Anonymity Sets with JavaScript

Henry Corrigan-Gibbs and Bryan Ford

Short paper
Workshop on Privacy in the Electronic Society (WPES)
November 4, 2013, Berlin, Germany

  • Proceedings version: PDF (318 KB)
  • Extended version: arXiv
  • Slides: PDF (3.9 MB), PPTx (2.4 MB)

We present the design and prototype implementation of ConScript, a framework for using JavaScript to allow casual Web users to participate in an anonymous communication system. When a Web user visits a cooperative Web site, the site serves a JavaScript application that instructs the browser to create and submit "dummy" messages into the anonymity system. Users who want to send non-dummy messages through the anonymity system use a browser plug-in to replace these dummy messages with real messages. Creating such conscripted anonymity sets can increase the anonymity set size available to users of remailer, e-voting, and verifiable shuffle-style anonymity systems. We outline ConScript's architecture, we address a number of potential attacks against ConScript, and we discuss the ethical issues related to deploying such a system. Our implementation results demonstrate the practicality of ConScript: a workstation running our ConScript prototype JavaScript client generates a dummy message for a mix-net in 81 milliseconds and it generates a dummy message for a DoS-resistant DC-net in 156 milliseconds.