InfoSec Seminar: Walking Onions: Scaling Anonymity Networks while Protecting Users

Speaker: Ian Goldberg

Date/Time: 08-Nov-2019, 16:00 UTC

Venue: Roberts 309



Scaling anonymity networks offers unique challenges. Due to the
distribution of trust on these networks, attackers can exploit differing
views of the network's topology to perform epistemic and route capture
attacks. Anonymity networks in practice, such as Tor, have opted for
security over scalability by requiring participants to share a global,
consistent view of all relays to prevent these kinds of attacks. Such an
approach requires each user to download information about every relay,
causing the total amount of data each user must download every epoch to
scale linearly with the number of relays. As the number of clients
increases, more relays must be added to provide bandwidth, further
exacerbating the total load on the network.
In this talk, we present Walking Onions, a set of protocols improving
scalability for anonymity networks by enabling constant-size scaling of
the information each user must download in every epoch. Walking Onions
offers the same security properties as current designs that require a
global, consistent network view, while bounding the amount of data about
the global state of the network each client must download.
This is joint work with Chelsea Komlo and Nick Mathewson.


Ian Goldberg is the Canada Research Chair in Privacy Enhancing
Technologies.  He is a Professor in the Cheriton School of Computer
Science at the University of Waterloo, where he is a founding member of
the Cryptography, Security, and Privacy (CrySP) research group.  He
holds a Ph.D. from the University of California, Berkeley, where he
discovered serious weaknesses in a number of widely deployed security
systems, including those used by cellular phones and wireless networks.
He also studied systems for protecting the personal privacy of Internet
users, which led to his role as Chief Scientist at Zero-Knowledge
Systems, a Montreal-based startup.  His research currently focuses on
developing usable and useful technologies to help Internet users
maintain their security and privacy.  He is a Distinguished Member of
the Association for Computing Machinery and a winner of the Outstanding
Young Computer Science Researcher Award, the Electronic Frontier
Foundation's Pioneer Award, the USENIX Security Test of Time Award,
and the Caspar Bowden Award for Outstanding Research in Privacy
Enhancing Technologies.



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