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On 10/23/2013 10:09 AM, Karsten Loesing wrote:<br>
<blockquote type="cite">Hello Tor relay operators,<br>
<br>
We could use your help in a pilot project to improve Tor security.
As<br>
you may be aware, the anonymity of a connection over Tor is
vulnerable<br>
to an adversary who can observe it in enough places along its
route.<br>
For example, traffic that crosses the same country as it enters
and<br>
leaves the Tor network can potentially be deanonymized by an
authority<br>
in that country who can monitor all network communication.
Researchers<br>
have been working to figure out how Tor traffic gets routed over
the<br>
Internet [0-3], but determining routes with high confidence has
been<br>
difficult.<br>
<br>
That's where you come in. To figure out where traffic travels from<br>
your relay, we'd like you to run a bunch of "traceroutes" -
network<br>
measurements that show the paths traffic takes. This is a one-time<br>
experiment for now, but, depending on what we find out, regularly<br>
making such measurements may become a part of Tor itself. We have<br>
already gotten some results thanks to Linus Nordberg of DFRI and<br>
Moritz Bartl of<br>
torservers.net, and now it's time to ask all relay operators to
help.<br>
We would like to start this right away.<br>
<br>
We have written some shell scripts to automate most of the
process.<br>
The easiest way for you to get them is with git, using the
following<br>
commands:<br>
<br>
git clone
<a class="moz-txt-link-freetext" href="https://bitbucket.org/anupam_das/traceroute-from-tor-relays">https://bitbucket.org/anupam_das/traceroute-from-tor-relays</a><br>
git checkout f253f768d14e3368e4fe4de9895acd2715a19412<br>
<br>
You can also just download the files directly by visiting [4].<br>
Detailed instructions for setting up and running the experiment
are in<br>
the README.<br>
<br>
Basically the experiment does traceroutes to three groups: all<br>
"routable IP prefixes", all Tor relays, and then all /24 subnets.<br>
These kinds of measurements are not uncommon, and they will not be<br>
done at a high rate. By default the scripts will periodically move
the<br>
results to our server [5] via SSH, although you can keep the
results<br>
around and/or not send them automatically if you wish (see the<br>
README). The traceroute data recorded is not sensitive or private
at<br>
all. We plan to make the code and data public, following Tor's<br>
practice of open cooperation with the research community [6].<br>
<br>
The measurements will work best if you have the "scamper" tool
from<br>
the Cooperative Association for Internet Data Analysis (CAIDA)<br>
installed (see the README for installation instructions). This is
a<br>
standard and open-source tool that handles the many modern<br>
complexities of Internet routing measurement. If you are not able
to<br>
run scamper, the script will also work with the more-common but<br>
less-accurate and slower "traceroute" utility. We do not currently<br>
have support for Windows relays. The output will take up around
500KB<br>
(110MB if you disable automatic removal after upload) disk space
if<br>
you use scamper; on the other hand if you use "traceroute" utility<br>
each output will be around 4MB (1GB with automatic removal after<br>
upload disabled). * *Depending on whether you run scamper or<br>
traceroute the total time required varies but results for
traceroutes<br>
to "routable IP prefixes" and all Tor relays should finish within
one<br>
week (possibly earlier). We would like to request relay operators
to<br>
upload those results once finished.* *<br>
<br>
This experiment is in collaboration with several researchers, but
the<br>
leads are Anupam Das, a Ph.D. student at the University of
Illinois at<br>
Urbana-Champaign, and his advisor Nikita Borisov. Based on a
review of<br>
the scripts of commit f253f768d14e3368e4fe4de9895acd2715a19412, we<br>
believe that they operate as described above. Please do read
through<br>
them yourself, and let us know if you have any questions or
concerns.<br>
And also feel free to contact any of us for help or with
suggestions.<br>
<br>
Because of you, Tor is the "king" of anonymous communication.
With<br>
your help, we will keep improving to face the new challenges to<br>
privacy and freedom online.<br>
<br>
Thank you,<br>
Karsten Loesing <a class="moz-txt-link-rfc2396E" href="mailto:karsten@torproject.org"><karsten@torproject.org></a><br>
Anupam Das <a class="moz-txt-link-rfc2396E" href="mailto:das17@illinois.edu"><das17@illinois.edu></a><br>
Nikita Borisov <a class="moz-txt-link-rfc2396E" href="mailto:nikita@illinois.edu"><nikita@illinois.edu></a><br>
<br>
[0] "Protecting anonymity in the presence of autonomous system and<br>
internet exchange level adversaries" by Joshua Juen. Master's
Thesis,<br>
UIUC. 2012.
<a class="moz-txt-link-rfc2396E" href="https://www.ideals.illinois.edu/handle/2142/34363"><https://www.ideals.illinois.edu/handle/2142/34363></a><br>
[1] "Users Get Routed: Traffic Correlation on Tor by Realistic<br>
Adversaries" by Aaron Johnson, Chris Wacek, Rob Jansen, Micah
Sherr,<br>
and Paul Syverson. ACM CCS 2013.<br>
<a class="moz-txt-link-rfc2396E" href="http://freehaven.net/anonbib/cache/ccs2013-usersrouted.pdf"><http://freehaven.net/anonbib/cache/ccs2013-usersrouted.pdf></a><br>
[2] "AS-awareness in Tor path selection" by Matthew Edman and Paul
F.<br>
Syverson. ACM CCS 2009.<br>
<a class="moz-txt-link-rfc2396E" href="http://freehaven.net/anonbib/cache/DBLP:conf/ccs/EdmanS09.pdf"><http://freehaven.net/anonbib/cache/DBLP:conf/ccs/EdmanS09.pdf></a><br>
[3] "Sampled Traffic Analysis by Internet-Exchange-Level
Adversaries"<br>
by Steven J. Murdoch and Piotr Zieliński. PETS 2007.<br>
<a class="moz-txt-link-rfc2396E" href="http://freehaven.net/anonbib/cache/murdoch-pet2007.pdf"><http://freehaven.net/anonbib/cache/murdoch-pet2007.pdf></a><br>
[4]
<a class="moz-txt-link-freetext" href="https://bitbucket.org/anupam_das/traceroute-from-tor-relays/downloads">https://bitbucket.org/anupam_das/traceroute-from-tor-relays/downloads</a><br>
[5] ttat-control.iti.illinois.edu<br>
[6] <a class="moz-txt-link-freetext" href="https://metrics.torproject.org/">https://metrics.torproject.org/</a><br>
</blockquote>
<br>
Is this Big Brother phishing for better ways to compromise the Tor
network?<br>
<br>
<br>
<span style="white-space: pre;">>
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