[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

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

Thus spake Roger Dingledine (arma@xxxxxxx):

> On Sat, Aug 28, 2010 at 11:20:41AM -0400, Paul Syverson wrote:
> 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.

Yes. This is the approach we need to solve this problem. However, one
of the problems with getting it out of most academics is the bias
against easy reproducibility. In order for any of this research to be
usable by us, it must be immediately and easily verifiable and
reproducible in the face of both changing attacks, and changing
network protocols (such as UDP-Tor and SPDY). This means source code
and experimental logs and data.

Most computer science academia is inherently biased against providing
this data for various reasons, and while this works for large industry
with the budget and time to reproduce experiments without assistance,
it will not work for us. I believe it is the main reason we see
adoption lag of 5-10 years for typical research all over
computer-related academia. My guess is Tor not have this much time to
fix these problems, hence we must demand better science from 
researchers who claim to be solving Tor-related problems (or proving
attacks on Tor networks).

I've gone into a little more detail on this subject and the
shortcomings of timing attacks in general in my comments on Michal
Zalewski's blog about regular, non-Tor HTTPS timing attacks:

Mike Perry
Mad Computer Scientist
fscked.org evil labs

Attachment: pgpyOs4rIIfx0.pgp
Description: PGP signature