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remove the reference to 2010 PETS.
Andrew Lewman
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at 2010-12-30 19:26:27
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## translation metadata # Revision: $Revision$ # Translation-Priority: 4-optional #include "head.wmi" TITLE="Tor: Research" CHARSET="UTF-8" <div id="content" class="clearfix"> <div id="breadcrumbs"> <a href="<page index>">Home » </a> <a href="<page getinvolved/research>">Research</a> </div> <div id="maincol"> <!-- PUT CONTENT AFTER THIS TAG --> <h2>Tor: Research</h2> <hr /> <p> Many people around the world are doing research on how to improve the Tor design, what's going on in the Tor network, and more generally on attacks and defenses for anonymous communication systems. This page summarizes the resources we provide to help make your Tor research more effective. The best way to reach us about research is through the <a href="<page about/contact>">tor-assistants</a> list. </p> <ul> <li> <b>Data.</b> We've been <a href="https://metrics.torproject.org/data.html">collecting data to learn more about the Tor network</a>: how many relays and clients there are in the network, what capabilities they have, how fast the network is, how many clients are connecting via bridges, what traffic exits the network, etc. We are also developing tools to process these huge data archives and come up with <a href="https://metrics.torproject.org/graphs.html">useful statistics</a>. For example, we provide a <a href="https://gitweb.torproject.org//ernie.git?a=blob_plain;f=doc/manual.pdf">tool called Ernie</a> that can import relay descriptors into a local database to perform analyses. Let us know what other information you'd like to see, and we can work with you to help make sure it gets collected <a href="https://metrics.torproject.org/papers/wecsr10.pdf">safely</a> and robustly. </li> <li> <b>Analysis.</b> If you're investigating Tor, or solving a Tor-related problem, <i>_please_</i> talk to us somewhere along the way — the earlier the better. These days we review too many conference paper submissions that make bad assumptions and end up solving the wrong problem. Since the Tor protocol and the Tor network are both moving targets, measuring things without understanding what's going on behind the scenes is going to result in bad conclusions. In particular, different groups often unwittingly run a variety of experiments in parallel, and at the same time we're constantly modifying the design to try new approaches. If you let us know what you're doing and what you're trying to learn, we can help you understand what other variables to expect and how to interpret your results. </li> <li> <b>Measurement and attack tools.</b> We're building a <a href="https://metrics.torproject.org/tools.html">repository</a> of tools that can be used to measure, analyze, or perform attacks on Tor. Many research groups end up needing to do similar measurements (for example, change the Tor design in some way and then see if latency improves), and we hope to help everybody standardize on a few tools and then make them really good. Also, while there are some really neat Tor attacks that people have published about, it's hard to track down a copy of the code they used. Let us know if you have new tools we should list, or improvements to the existing ones. The more the better, at this stage. </li> <li> <b>We need defenses too — not just attacks.</b> Most researchers find it easy and fun to come up with novel attacks on anonymity systems. We've seen this result lately in terms of improved congestion attacks, attacks based on remotely measuring latency or throughput, and so on. Knowing how things can go wrong is important, and we recognize that the incentives in academia aren't aligned with spending energy on designing defenses, but it sure would be great to get more attention to how to address the attacks. We'd love to help brainstorm about how to make Tor better. As a bonus, your paper might even end up with a stronger "countermeasures" section. </li> <li> <b>In-person help.</b> If you're doing interesting and important Tor research and need help understanding how the Tor network or design works, interpreting your data, crafting your experiments, etc, we can send a Tor researcher to your doorstep. As you might expect, we don't have a lot of free time; but making sure that research is done in a way that's useful to us is really important. So let us know, and we'll work something out. </li> </ul> <a id="Groups"></a> <h2><a class="anchor" href="#Groups">Research Groups</a></h2> <p>Interested to find other anonymity researchers? Here are some research groups you should take a look at.</p> <ul> <li>Ian Goldberg's <a href="http://crysp.uwaterloo.ca/">CrySP</a> group at Waterloo. </li> <li><a href="http://www-users.cs.umn.edu/~hopper/">Nick Hopper</a>'s group at UMN. </li> <li><a href="http://www.hatswitch.org/~nikita/">Nikita Borisov</a>'s group at Illinois. </li> <li>Matt Wright's <a href="http://isec.uta.edu/">iSec</a> group at UTA. </li> </ul> <a id="Ideas"></a> <h2><a class="anchor" href="#Ideas">Research Ideas</a></h2> <p> If you're interested in anonymity research, you must make it to the <a href="http://petsymposium.org/">Privacy Enhancing Technologies Symposium</a>. Everybody who's anybody in the anonymity research world will be there. Stipends are generally available for people whose presence will benefit the community. </p> <p>To get up to speed on anonymity research, read <a href="http://freehaven.net/anonbib/">these papers</a> (especially the ones in boxes).</p> <p>We need people to attack the system, quantify defenses, etc. Here are some example projects:</p> <ul> <li>If we prevent the really loud users from using too much of the Tor network, how much can it help? We've instrumented Tor's entry relays so they can rate-limit connections from users, and we've instrumented the directory authorities so they can change the rate-limiting parameters globally across the network. Which parameter values improve performance for the Tor network as a whole? How should relays adapt their rate-limiting parameters based on their capacity and based on the network load they see, and what rate-limiting algorithms will work best? See the <a href="<blog>/research-problem-adaptive-throttling-tor-clients-entry-guards">blog post</a> for details. </li> <li>Right now Tor clients are willing to reuse a given circuit for ten minutes after it's first used. The goal is to avoid loading down the network with too many circuit creations, yet to also avoid having clients use the same circuit for so long that the exit node can build a useful pseudonymous profile of them. Alas, ten minutes is probably way too long, especially if connections from multiple protocols (e.g. IM and web browsing) are put on the same circuit. If we keep fixed the overall number of circuit extends that the network needs to do, are there more efficient and/or safer ways for clients to allocate streams to circuits, or for clients to build preemptive circuits? Perhaps this research item needs to start with gathering some traces of what requests typical clients try to launch, so you have something realistic to try to optimize. </li> <li>The "website fingerprinting attack": make a list of a few hundred popular websites, download their pages, and make a set of "signatures" for each site. Then observe a Tor client's traffic. As you watch him receive data, you quickly approach a guess about which (if any) of those sites he is visiting. First, how effective is this attack on the deployed Tor design? The problem with all the previous attack papers is that they look at timing and counting of IP packets on the wire. But OpenSSL's TLS records, plus Tor's use of TCP pushback to do rate limiting, means that tracing by IP packets produces very poor results. The right approach is to realize that Tor uses OpenSSL, look inside the TLS record at the TLS headers, and figure out how many 512-byte cells are being sent or received. Then start exploring defenses: for example, we could change Tor's cell size from 512 bytes to 1024 bytes, we could employ padding techniques like <a href="http://freehaven.net/anonbib/#timing-fc2004">defensive dropping</a>, or we could add traffic delays. How much of an impact do these have, and how much usability impact (using some suitable metric) is there from a successful defense in each case?</li> <!-- <li> Path selection algorithms, directory fetching schedules for Tor-on-mobile that are compatible anonymity-wise with our current approaches. </li> --> <li>More coming soon. See also the "Research" section of the <a href="<page getinvolved/volunteer>#Research">volunteer</a> page for other topics. </li> </ul> </div> <!-- END MAINCOL --> <div id = "sidecol"> #include "side.wmi" #include "info.wmi" </div> <!-- END SIDECOL --> </div> <!-- END CONTENT --> #include <foot.wmi>