Karsten Loesing commited on 2012-08-20 09:23:26
Zeige 2 geänderte Dateien mit 1 Einfügungen und 227 Löschungen.
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-# Revision: $Revision$ |
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-# Translation-Priority: 4-optional |
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-#include "head.wmi" TITLE="Tor: Research" CHARSET="UTF-8" |
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-<div id="content" class="clearfix"> |
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- <div id="breadcrumbs"> |
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- <a href="<page index>">Home » </a> |
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- <a href="<page getinvolved/research>">Research</a> |
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- </div> |
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- <div id="maincol"> |
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- <!-- PUT CONTENT AFTER THIS TAG --> |
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-<h2>Tor: Research</h2> |
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-<hr /> |
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- |
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-<p> |
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-Many people around the world are doing research on how to improve the Tor |
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-design, what's going on in the Tor network, and more generally on attacks |
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-and defenses for anonymous communication systems. This page summarizes |
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-the resources we provide to help make your Tor research more effective. |
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-The best way to reach us about research is through the <a href="<page |
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-about/contact>">tor-assistants</a> list. |
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-</p> |
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- |
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-<ul> |
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- |
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-<li> |
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-<b>Data.</b> |
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-We've been <a href="https://metrics.torproject.org/data.html">collecting |
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-data to learn more about the Tor network</a>: how many relays and |
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-clients there are in the network, what capabilities they have, how |
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-fast the network is, how many clients are connecting via bridges, |
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-what traffic exits the network, etc. We are also developing |
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-tools to process these huge data archives and come up with |
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-<a href="https://metrics.torproject.org/graphs.html">useful |
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-statistics</a>. Let us know what other information you'd like to |
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-see, and we can work with you to help make sure it gets collected |
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-<a href="https://metrics.torproject.org/papers/wecsr10.pdf">safely</a> |
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-and robustly. |
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-</li> |
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- |
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-<li> |
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-<b>Analysis.</b> |
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-If you're investigating Tor, or solving a Tor-related problem, |
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-<i>_please_</i> talk to us somewhere along the way — the earlier |
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-the better. These days we review too many conference paper submissions |
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-that make bad assumptions and end up solving the wrong problem. Since |
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-the Tor protocol and the Tor network are both moving targets, measuring |
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-things without understanding what's going on behind the scenes is going |
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-to result in bad conclusions. In particular, different groups often |
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-unwittingly run a variety of experiments in parallel, and at the same |
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-time we're constantly modifying the design to try new approaches. If |
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-you let us know what you're doing and what you're trying to learn, |
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-we can help you understand what other variables to expect and how to |
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-interpret your results. |
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-</li> |
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- |
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-<li> |
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-<b>Measurement and attack tools.</b> |
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-We're building a <a |
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-href="https://metrics.torproject.org/tools.html">repository</a> of tools |
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-that can be used to measure, analyze, or perform attacks on Tor. Many |
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-research groups end up needing to do similar measurements (for example, |
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-change the Tor design in some way and then see if latency improves), |
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-and we hope to help everybody standardize on a few tools and then make |
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-them really good. Also, while there are some really neat Tor attacks |
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-that people have published about, it's hard to track down a copy of |
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-the code they used. Let us know if you have new tools we should list, |
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-or improvements to the existing ones. The more the better, at this stage. |
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-</li> |
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- |
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-<li> |
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-<b>We need defenses too — not just attacks.</b> |
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-Most researchers find it easy and fun to come up with novel attacks on |
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-anonymity systems. We've seen this result lately in terms of improved |
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-congestion attacks, attacks based on remotely measuring latency or |
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-throughput, and so on. Knowing how things can go wrong is important, |
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-and we recognize that the incentives in academia aren't aligned with |
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-spending energy on designing defenses, but it sure would be great to |
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-get more attention to how to address the attacks. We'd love to help |
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-brainstorm about how to make Tor better. As a bonus, your paper might |
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-even end up with a stronger "countermeasures" section. |
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-</li> |
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- |
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-<li> |
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-<b>In-person help.</b> |
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-If you're doing interesting and important Tor research and need help |
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-understanding how the Tor network or design works, interpreting your |
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-data, crafting your experiments, etc, we can send a Tor researcher to |
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-your doorstep. As you might expect, we don't have a lot of free time; |
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-but making sure that research is done in a way that's useful to us is |
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-really important. So let us know, and we'll work something out. |
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-</li> |
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- |
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-</ul> |
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- |
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-<a id="Groups"></a> |
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-<h2><a class="anchor" href="#Groups">Research Groups</a></h2> |
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- |
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-<p>Interested to find other anonymity researchers? Here are some |
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-research groups you should take a look at.</p> |
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- |
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-<ul> |
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-<li>Ian Goldberg's <a href="http://crysp.uwaterloo.ca/">CrySP</a> group |
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-at Waterloo. |
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-</li> |
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-<li><a href="http://www-users.cs.umn.edu/~hopper/">Nick Hopper</a>'s |
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-group at UMN. |
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-</li> |
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-<li><a href="http://www.hatswitch.org/~nikita/">Nikita Borisov</a>'s |
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-group at Illinois. |
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-</li> |
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-<li>Micah Sherr's <a href="https://security.cs.georgetown.edu/">SecLab</a> |
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-group at Georgetown. |
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-</li> |
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-<li>Matt Wright's <a href="http://isec.uta.edu/">iSec</a> group at |
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-UTA. |
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-</li> |
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-</ul> |
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- |
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-<a id="Ideas"></a> |
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-<h2><a class="anchor" href="#Ideas">Research Ideas</a></h2> |
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- |
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-<p> |
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-If you're interested in anonymity research, you must make it to the |
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-<a href="http://petsymposium.org/">Privacy Enhancing Technologies |
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-Symposium</a>. Everybody who's anybody in the anonymity research world |
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-will be there. Stipends are generally available for people whose presence |
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-will benefit the community. |
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-</p> |
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- |
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-<p>To get up to speed on anonymity research, read <a |
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-href="http://freehaven.net/anonbib/">these papers</a> (especially the |
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-ones in boxes).</p> |
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- |
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-<p>We need people to attack the system, quantify defenses, |
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-etc. Here are some example projects:</p> |
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- |
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-<ul> |
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- |
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-<li>What algorithm should we use to assign Guard flags such that a) |
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-we assign the flag to as many relays as possible, yet b) we minimize |
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-the chance that Alice will use an attacker's node as a guard? See the |
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-<a href="<blog>/research-problem-better-guard-rotation-parameters">blog |
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-post</a> for details. |
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-</li> |
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- |
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-<li>For various diversity metrics, how has the diversity of |
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-the Tor network changed over time? How robust is it to change or |
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-attack? These results can help us make better design decisions. See the <a |
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-href="<blog>/research-problem-measuring-safety-tor-network">blog post</a> |
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-for details. |
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-</li> |
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- |
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-<li>If we prevent the really loud users from using too much of the Tor |
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-network, how much can it help? We've instrumented Tor's entry relays |
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-so they can rate-limit connections from users, and we've instrumented |
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-the directory authorities so they can change the rate-limiting |
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-parameters globally across the network. Which parameter values improve |
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-performance for the Tor network as a whole? How should relays adapt |
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-their rate-limiting parameters based on their capacity and based on |
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-the network load they see, and what rate-limiting algorithms will work |
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-best? See the <a |
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-href="<blog>/research-problem-adaptive-throttling-tor-clients-entry-guards">blog |
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-post</a> for details. |
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-</li> |
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- |
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-<li>Right now Tor clients are willing to reuse a given circuit for ten |
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-minutes after it's first used. The goal is to avoid loading down the |
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-network with too many circuit creations, yet to also avoid having |
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-clients use the same circuit for so long that the exit node can build a |
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-useful pseudonymous profile of them. Alas, ten minutes is probably way |
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-too long, especially if connections from multiple protocols (e.g. IM and |
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-web browsing) are put on the same circuit. If we keep fixed the overall |
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-number of circuit extends that the network needs to do, are there more |
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-efficient and/or safer ways for clients to allocate streams to circuits, |
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-or for clients to build preemptive circuits? Perhaps this research item |
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-needs to start with gathering some traces of what requests typical |
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-clients try to launch, so you have something realistic to try to optimize. |
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-</li> |
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- |
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-<li>The "website fingerprinting attack": make a list of a few |
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-hundred popular websites, download their pages, and make a set of |
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-"signatures" for each site. Then observe a Tor client's traffic. As |
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-you watch him receive data, you quickly approach a guess about which |
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-(if any) of those sites he is visiting. First, how effective is |
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-this attack on the deployed Tor design? The problem with all the |
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-previous attack papers is that they look at timing and counting of |
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-IP packets on the wire. But OpenSSL's TLS records, plus Tor's use of |
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-TCP pushback to do rate limiting, means that tracing by IP packets |
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-produces very poor results. The right approach is to realize that |
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-Tor uses OpenSSL, look inside the TLS record at the TLS headers, and |
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-figure out how many 512-byte cells are being sent or received. Then |
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-start exploring defenses: for example, we could change Tor's cell |
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-size from 512 bytes to 1024 bytes, we could employ padding techniques |
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-like <a href="http://freehaven.net/anonbib/#timing-fc2004">defensive |
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-dropping</a>, or we could add traffic delays. How much of an impact do |
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-these have, and how much usability impact (using some suitable metric) |
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-is there from a successful defense in each case?</li> |
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- |
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-<!-- |
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-<li> |
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-Path selection algorithms, directory fetching schedules for Tor-on-mobile |
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-that are compatible anonymity-wise with our current approaches. |
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-</li> |
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- |
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---> |
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- |
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-<li>More coming soon. See also the "Research" section of the <a |
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-href="<page getinvolved/volunteer>#Research">volunteer</a> page for |
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-other topics. |
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-</li> |
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- |
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-</ul> |
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- |
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- </div> |
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- <!-- END MAINCOL --> |
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- <div id = "sidecol"> |
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-#include "side.wmi" |
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-#include "info.wmi" |
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- </div> |
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- <!-- END SIDECOL --> |
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-</div> |
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-<!-- END CONTENT --> |
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-#include <foot.wmi> |
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- |