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5) #include "head.wmi" TITLE="Tor: Research" CHARSET="UTF-8"

6) 
7) <div class="main-column">
8) 
9) <h2>Tor: Research</h2>
10) <hr />
11) 

12) <p>
13) Many people around the world are doing research on how to improve the Tor
14) design, what's going on in the Tor network, and more generally on attacks
15) and defenses for anonymous communication systems. This page summarizes
16) the resources we provide to help make your Tor research more effective.
17) The best way to reach us about research is through the <a href="<page
18) contact>">tor-assistants</a> list.
19) </p>
20) 
21) <ul>
22) 
23) <li>
24) <b>Data.</b>
25) We've been <a href="http://metrics.torproject.org/data.html">collecting
26) data to learn more about the Tor network</a>: how many relays and
27) clients there are in the network, what capabilities they have, how
28) fast the network is, how many clients are connecting via bridges,
29) what traffic exits the network, etc. We are also developing
30) tools to process these huge data archives and come up with
31) <a href="http://metrics.torproject.org/graphs.html">useful
32) statistics</a>.  For example, we provide a <a
33) href="https://gitweb.torproject.org//ernie.git?a=blob_plain;f=doc/manual.pdf">tool
34) called Ernie</a> that can import relay descriptors into a local database
35) to perform analyses. Let us know what other information you'd like to
36) see, and we can work with you to help make sure it gets collected safely
37) and robustly.
38) </li>
39) 
40) <li>
41) <b>Analysis.</b>
42) If you're investigating Tor, or solving a Tor-related problem,
43) <i>_please_</i> talk to us somewhere along the way &mdash; the earlier
44) the better. These days we review too many conference paper submissions
45) that make bad assumptions and end up solving the wrong problem. Since
46) the Tor protocol and the Tor network are both moving targets, measuring
47) things without understanding what's going on behind the scenes is going
48) to result in bad conclusions. In particular, different groups often
49) unwittingly run a variety of experiments in parallel, and at the same
50) time we're constantly modifying the design to try new approaches. If
51) you let us know what you're doing and what you're trying to learn,
52) we can help you understand what other variables to expect and how to
53) interpret your results.
54) </li>
55) 
56) <li>
57) <b>Measurement and attack tools.</b>
58) We're building a <a
59) href="http://metrics.torproject.org/tools.html">repository</a> of tools
60) that can be used to measure, analyze, or perform attacks on Tor. Many
61) research groups end up needing to do similar measurements (for example,
62) change the Tor design in some way and then see if latency improves),
63) and we hope to help everybody standardize on a few tools and then make
64) them really good. Also, while there are some really neat Tor attacks
65) that people have published about, it's hard to track down a copy of
66) the code they used. Let us know if you have new tools we should list,
67) or improvements to the existing ones. The more the better, at this stage.
68) </li>
69) 

70) <li>
71) <b>We need defenses too &mdash; not just attacks.</b>
72) Most researchers find it easy and fun to come up with novel attacks on
73) anonymity systems. We've seen this result lately in terms of improved
74) congestion attacks, attacks based on remotely measuring latency or
75) throughput, and so on. Knowing how things can go wrong is important,
76) and we recognize that the incentives in academia aren't aligned with
77) spending energy on designing defenses, but it sure would be great to
78) get more attention to how to address the attacks. We'd love to help
79) brainstorm about how to make Tor better. As a bonus, your paper might
80) even end up with a stronger "countermeasures" section.
81) </li>
82) 

83) <li>
84) <b>In-person help.</b>
85) If you're doing interesting and important Tor research and need help
86) understanding how the Tor network or design works, interpreting your
87) data, crafting your experiments, etc, we can send a Tor researcher to
88) your doorstep. As you might expect, we don't have a lot of free time;
89) but making sure that research is done in a way that's useful to us is
90) really important. So let us know, and we'll work something out.
91) </li>
92) 
93) </ul>
94) 
95) <a id="Groups"></a>
96) <h2><a class="anchor" href="#Ideas">Research Groups</a></h2>
97) 
98) <p>Interested to find other anonymity researchers? Here are some
99) research groups you should take a look at.</p>
100) 
101) <ul>
102) <li>Ian Goldberg's <a href="http://crysp.uwaterloo.ca/">CrySP</a> group
103) at Waterloo.
104) </li>
105) <li><a href="http://www-users.cs.umn.edu/~hopper/">Nick Hopper</a>'s
106) group at UMN.
107) </li>
108) <li><a href="http://www.hatswitch.org/~nikita/">Nikita Borisov</a>'s
109) group at Illinois.
110) </li>
111) <li>Matt Wright's <a href="http://isec.uta.edu/">iSec</a> group at
112) UTA.
113) </li
114) </ul>
115) 
116) <a id="Ideas"></a>
117) <h2><a class="anchor" href="#Ideas">Research Ideas</a></h2>
118) 
119) <p>
120) If you're interested in anonymity research, you must make it to the
121) <a href="http://petsymposium.org/">Privacy Enhancing Technologies
122) Symposium</a>. Everybody who's anybody in the anonymity research world
123) will be there. The 2010 conference is in Berlin in July. Stipends are
124) available for people whose presence will benefit the community.
125) </p>
126) 
127) <p>To get up to speed on anonymity research, read <a
128) href="http://freehaven.net/anonbib/">these papers</a> (especially the
129) ones in boxes).</p>

130) 
131) <p>We need people to attack the system, quantify defenses,

132) etc. Here are some example projects:
133) 
134) <ul>
135) 
136) <li>The "website fingerprinting attack": make a list of a few
137) hundred popular websites, download their pages, and make a set of
138) "signatures" for each site. Then observe a Tor client's traffic. As
139) you watch him receive data, you quickly approach a guess about which
140) (if any) of those sites he is visiting. First, how effective is
141) this attack on the deployed Tor design? The problem with all the
142) previous attack papers is that they look at timing and counting of
143) IP packets on the wire. But OpenSSL's TLS records, plus Tor's use of
144) TCP pushback to do rate limiting, means that tracing by IP packets
145) produces very poor results. The right approach is to realize that
146) Tor uses OpenSSL, look inside the TLS record at the TLS headers, and
147) figure out how many 512-byte cells are being sent or received. Then
148) start exploring defenses: for example, we could change Tor's cell
149) size from 512 bytes to 1024 bytes, we could employ padding techniques
150) like <a href="http://freehaven.net/anonbib/#timing-fc2004">defensive
151) dropping</a>, or we could add traffic delays. How much of an impact do
152) these have, and how much usability impact (using some suitable metric)
153) is there from a successful defense in each case?</li>
154) </li>
155) 
156) <!--
157) <li>
158) Path selection algorithms, directory fetching schedules for Tor-on-mobile
159) that are compatible anonymity-wise with our current approaches.
160) </li>
161) 
162) <li>
163) Figure out how bad 10 minutes is for maxcircuitdirtiness.
164) </li>
165) -->
166) 
167) <li>More coming soon. See also the "Research" section of the
168) <a href="<page volunteer>#Research">volunteer</a> page for other topics.
169) </li>
170) 
171) </ul>