Re: Low-Cost Traffic Analysis of Tor

["Eugene Y. Vasserman" <eyv@xxxxxxxxxx>]

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Greetings. Let me introduce myself. I'm a grad student and the U of MN
in computer science. I've been working on anonymous network systems. I
also had a chance to play with Tor, and read the "Low-Cost Traffic
Analysis of Tor" paper (mentioned below).
I have a general question: this may or may not decrease performance, but
wouldn't locking and/or randomizing bandwidth per flow through a Tor
server solve this problem? This attack seem comparable to a variant on
SSL (and general crypto) timing attacks. Similar solutions could be
applied. Also, since this attack relies on a malicious node being able
to estimate its flow's likely performance through an honest node at any
given time, Tor could apply a somewhat more complex mixing approach,
making this attack more difficult. I was thinking of something like
lottery scheduling, which is really easy to implement and, if done
right, will not impose any noticeable CPU overhead, and still provide
the same (albeit probabilistic, not deterministic) throughput guarantees
for every flow. Please let me know your thoughts. I will hopefully have
some time to spend implementing this in the near future, if there is a
consensus that some of these suggestions would help.
Thanks,
Eugene

In reference to the paper:
http://www.cl.cam.ac.uk/users/sjm217/papers/oakland05torta.pdf

- --
Eugene Y. Vasserman
http://www.cs.umn.edu/~eyv/
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