Georgetown Law
Technology Review

This Technology Explainer covers pluggable transports,1See, e.g., Meet the Transports, Pluggable Transports, https://www.pluggabletransports.
info/transports [https://perma.cc/E3NX-XVR6]; see generally Roger Dingledine, The Tor Censorship Arms Race: The Next Chapter, defcon (Nov. 15, 2019), https://blog.torproject.
org/next-chapter-anti-censorship [https://perma.cc/6YG9-TK5L]. While often described as a cat-and-mouse game, this “arms race” does not necessarily lead censors to use the most cutting-edge censorship tools, with some preferring more blunt techniques to save on costs associated with censorship. For a discussion of some of the various methods of network censorship available to censors, see Joseph Lorenzo Hall et al., A Survey of Worldwide Censorship Techniques, privacy enhancements and assessments res. grp. – internet eng’g task force (May 18, 2020), https://tools.ietf.org/id/draft-irtf-pearg-censorship-03.html [https://perma.cc/F4GH-UJYC]. an obfuscation tool that disguises a user’s network traffic to avoid certain traffic analysis and detection methods. 2For developments to pluggable transports, see Pluggable Transports, supra note 1. Pluggable transports are like plugins—the term refers to their ability to “plug in” and swap out, which affords developers and users the chance to try different circumvention strategies in the same app once one method stops working. 3Brandon Wiley & David Oliver, Enabling Network Traffic Obfuscation – Pluggable Transports, ietf networking working grp. (July 8, 2019), https://tools.ietf.org/html/draft-oliver-pluggable-transports-00 [https://perma.cc/EL56-CK32]. Software developers created pluggable transports in reaction to censors targeting and blocking anonymity tools used to circumvent censorship.4See, e.g., Mohammad Hassan Soleimani et al., Real-time Identification of Three Tor Pluggable Transports Using Machine Learning Techniques, j. of supercomputing 2 (Feb. 6, 2018), https://dl.acm.org/doi/10.5555/3288339.3288350 [https://perma.cc/2XED-K5VK].

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