Re: Tor seems to have a huge security risk--please prove me wrong!

[Roger Dingledine <arma@xxxxxxx>]

On Sat, Aug 28, 2010 at 11:20:41AM -0400, Paul Syverson wrote:
> What you describe is known in the literature as website fingerprinting
> attacks,
[snip]
> Roughly, while Tor is not invulnerable to such an attack, it fairs
> pretty well, much better than other systems that this and earlier
> papers examined mostly because the uniform size cells that Tor moves
> all data with adds lots of noise.

Maybe. Or maybe not. This is an open research area that continues to
worry me.

I keep talking to professors and grad students who have started a paper
showing that website fingerprinting works on Tor, and after a while they
stop working on the paper because they can't get good results either way
(they can't show that it works well, and they also can't show that it
doesn't work well).

The real question I want to see answered is not "does it work" -- I bet
it can work in some narrow situations even if it doesn't work well in
the general case. Rather, I want to know how to make it work less well.
But we need to have a better handle on how well it works before we can
answer that harder question.

For those who want more background, you can read more at item #1 on
https://www.torproject.org/research.html.en#Ideas
(I hoped to transition
https://www.torproject.org/volunteer.html.en#Research over to that new
page, but haven't gotten around to finishing)

or see my 25c3 talk from 2008:
http://events.ccc.de/congress/2008/Fahrplan/events/2977.en.html
http://media.torproject.org/video/25c3-2977-en-security_and_anonymity_vulnerabilities_in_tor.mp4

--Roger

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