getinvolved/en/volunteer.wml (8dcd28de0) - tor-webwml.git

volunteer.wml

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#include "head.wmi" TITLE="Tor: Volunteer" CHARSET="UTF-8"
<div id="content" class="clearfix">
 <div id="breadcrumbs">
 <a href="<page index>">Home &raquo; </a>
 <a href="<page getinvolved/volunteer>">Volunteer</a>
 </div>
 <div id="maincol"> 
 
 <h1>A few things everyone can do now:</h1>
 <ol>
 <li>Please consider <a href="<page docs/tor-doc-relay>">running
 a relay</a> to help the Tor network grow.</li>
 <li>Do you have an Amazon account? Are you willing to spend up to $3 a
 month? Then spin up your own Tor <a href="<page
 docs/bridges>">bridge</a> in less than 10 minutes with <a
 href="https://cloud.torproject.org/">tor cloud</a>!</li>
 <li>Tell your friends! Get them to run relays. Get them to run hidden
 services. Get them to tell their friends.</li>
 <li>If you like Tor's goals, please <a href="<page donate/donate>">take a moment
 to donate to support further Tor development</a>. We're also looking
 for more sponsors &mdash; if you know any companies, NGOs, agencies,
 or other organizations that want anonymity / privacy / communications
 security, let them know about us.</li>
 <li>We're looking for more <a href="<page about/torusers>">good examples of Tor
 users and Tor use cases</a>. If you use Tor for a scenario or purpose not
 yet described on that page, and you're comfortable sharing it with us,
 we'd love to hear from you.</li>
 </ol>
 
 <a id="Documentation"></a>
 <h2><a class="anchor" href="#Documentation">Documentation</a></h2>
 <ol>
 <li>Help translate the web page and documentation into other
 languages. See the <a href="<page getinvolved/translation>">translation
 guidelines</a> if you want to help out. We especially need Arabic or
 Farsi translations, for the many Tor users in censored areas.</li>
 <li>Evaluate and document
 <a href="<wiki>doc/TorifyHOWTO">our
 list of programs</a> that can be configured to use Tor.</li>
 <li>We have a huge list of <a
 href="<wiki>doc/SupportPrograms">potentially useful
 programs that interface to Tor</a>. Which ones are useful in which
 situations? Please help us test them out and document your results.</li>
 </ol>
 
 <a id="Advocacy"></a>
 <h2><a class="anchor" href="#Advocacy">Advocacy</a></h2>
 <ol>
 <li>Create a presentation that can be used for various user group
meetings around the world.</li>
 <li>Create a video about the positive uses of Tor, what Tor is,
 or how to use it. Some have already started on <a
 href="https://media.torproject.org/video/">Tor's Media server</a>,
 <a
 href="http://www.howcast.com/videos/90601-How-To-Circumvent-an-Internet-Proxy">Howcast</a>,
 and <a href="http://www.youtube.com/thetorproject">YouTube</a>.</li> 
 <li>Create a poster, or a set of posters, around a theme,
 such as "Tor for Freedom!".</li>
 <li>Create a t-shirt design that incorporates "Congratulations!
 You are using Tor!" in any language.</li>
 </ol>
 
 <a id="Projects"></a>
 <h2><a class="anchor" href="#Projects">Projects</a></h2>
 
 
 Below are a list of Tor related projects we're developing and/or
 maintaining. Most discussions happen on IRC so if you're interested in any
 of these (or you have a project idea of your own), then please <a
 href="<page about/contact>#irc">join us in #tor-dev</a>. Don't be shy
 to ask questions, and don't hesitate to ask even if the main contributors
 aren't active at that moment.
 
 
 <table id="projects">
 <tr>
 <th>Name</th>
 <th>Category</th>
 <th>Language</th>
 <th>Activity</th>
 <th>Contributors</th>
 </tr>
 
 <tr>
 <td><a href="#project-tor">Tor</a></td>
 <td>Core</td>
 <td>C</td>
 <td>Heavy</td>
 <td>nickm, arma, Sebastian</td>
 </tr>
 
 <tr class="alt">
 <td>*<a href="#project-jtor">JTor</a></td>
 <td>Core</td>
 <td>Java</td>
 <td>None</td>
 <td></td>
 </tr>
 
 <tr>
 <td><a href="#project-tbb">TBB</a></td>
 <td>Usability</td>
 <td>Sys Admin</td>
 <td>Moderate</td>
 <td>Erinn</td>
 </tr>
 
 <tr class="alt">
 <td><a href="#project-tails">Tails</a></td>
 <td>Usability</td>
 <td>Sys Admin</td>
 <td>Heavy</td>
 <td><a href="https://tails.boum.org/chat/">#tails</a></td>
 </tr>
 
 <tr>
 <td><a href="#project-torsocks">Torsocks</a></td>
 <td>Usability</td>
 <td>C</td>
 <td>None</td>
 <td>mwenge</td>
 </tr>
 
 <tr class="alt">
 <td>*<a href="#project-torouter">Torouter</a></td>
 <td>Usability</td>
 <td>Sys Admin</td>
 <td>Light</td>
 <td>ioerror, Runa</td>
 </tr>
 
 <tr>
 <td><a href="#project-vidalia">Vidalia</a></td>
 <td>User Interface</td>
 <td>C++, Qt</td>
 <td>Light</td>
 <td>chiiph</td>
 </tr>
 
 <tr class="alt">
 <td><a href="#project-arm">Arm</a></td>
 <td>User Interface</td>
 <td>Python, Curses</td>
 <td>Light</td>
 <td>atagar</td>
 </tr>
 
 <tr>
 <td><a href="#project-orbot">Orbot</a></td>
 <td>User Interface</td>
 <td>Java</td>
 <td>Moderate</td>
 <td>n8fr8</td>
 </tr>
 
 <tr class="alt">
 <td><a href="#project-torbutton">Torbutton</a></td>
 <td>Browser Add-on</td>
 <td>Javascript</td>
 <td>Moderate</td>
 <td>mikeperry</td>
 </tr>
 
 <tr>
 <td><a href="#project-obfsproxy">Obfsproxy</a></td>
 <td>Client Add-on</td>
 <td>C</td>
 <td>Moderate</td>
 <td>nickm, asn</td>
 </tr>
 
 <tr class="alt">
 <td>*<a href="#project-thandy">Thandy</a></td>
 <td>Updater</td>
 <td>Python</td>
 <td>Light</td>
 <td>chiiph, Erinn, nickm</td>
 </tr>
 
 <tr>
 <td>*<a href="#project-ooni-probe">Ooni Probe</a></td>
 <td>Scanner</td>
 <td>Python</td>
 <td>Moderate</td>
 <td>hellais, ioerror</td>
 </tr>
 
 <tr class="alt">
 <td><a href="#project-shadow">Shadow</a></td>
 <td>Experimentation</td>
 <td>C, Python</td>
 <td>Moderate</td>
 <td>robgjansen</td>
 </tr>
 
 <tr>
 <td><a href="#project-torctl">TorCtl</a></td>
 <td>Library</td>
 <td>Python</td>
 <td>Light</td>
 <td>mikeperry</td>
 </tr>
 
 <tr class="alt">
 <td>*<a href="#project-stem">Stem</a></td>
 <td>Library</td>
 <td>Python</td>
 <td>Heavy</td>
 <td>atagar</td>
 </tr>
 
 <tr>
 <td><a href="#project-metrics">Metrics</a></td>
 <td>Client Service</td>
 <td>Java</td>
 <td>Heavy</td>
 <td>karsten</td>
 </tr>
 
 <tr class="alt">
 <td><a href="#project-torstatus">TorStatus</a></td>
 <td>Client Service</td>
 <td>Python, Django</td>
 <td>None</td>
 <td></td>
 </tr>
 
 <tr>
 <td><a href="#project-weather">Weather</a></td>
 <td>Client Service</td>
 <td>Python</td>
 <td>None</td>
 <td>kaner</td>
 </tr>
 
 <tr class="alt">
 <td><a href="#project-gettor">GetTor</a></td>
 <td>Client Service</td>
 <td>Python</td>
 <td>None</td>
 <td>kaner</td>
 </tr>
 
 <tr>
 <td><a href="#project-torcheck">TorCheck</a></td>
 <td>Client Service</td>
 <td>Python, Perl</td>
 <td>None</td>
 <td></td>
 </tr>
 
 <tr class="alt">
 <td><a href="#project-bridgedb">BridgeDB</a></td>
 <td>Backend Service</td>
 <td>Python</td>
 <td>None</td>
 <td>kaner, nickm</td>
 </tr>
 
 <tr>
 <td><a href="#project-torflow">TorFlow</a></td>
 <td>Backend Service</td>
 <td>Python</td>
 <td>Moderate</td>
 <td>mikeperry</td>
 </tr>
 
 <tr class="alt">
 <td>*<a href="#project-torbel">TorBEL</a></td>
 <td>Backend Service</td>
 <td>Python</td>
 <td>None</td>
 <td>Sebastian</td>
 </tr>
 </table>
 
 
 * Project is still in an alpha state.
 
 
 
 
 <a id="project-tor"></a>
 <h3>Tor (<a href="https://gitweb.torproject.org/tor.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Tor+Client&component=Tor+Relay&component=vidalia&order=priority">bug
 tracker</a>)</h3>
 
 
 Central project, providing the core software for using and participating in
 the Tor network. Numerous people contribute to the project to varying
 extents, but the chief architects are Nick Mathewson and Roger Dingledine.
 
 
 
 Project Ideas: 
 <a href="#resistCensorship">Improving Tor's ability to resist
 censorship</a>
 
 
 <a id="project-jtor"></a>
 <h3><a href="https://github.com/brl/JTor/wiki">JTor</a> (<a
 href="https://github.com/brl/JTor">code</a>, <a
 href="https://github.com/brl/JTor/issues">bug
 tracker</a>)</h3>
 
 
 Java implementation of Tor and successor to <a
 href="http://onioncoffee.sourceforge.net/">OnionCoffee</a>. This project
 isn't yet complete, and has been inactive since Fall 2010.
 
 
 <a id="project-tbb"></a>
 <h3><a href="<page projects/torbrowser>">Tor Browser Bundle</a> (<a
 href="https://gitweb.torproject.org/torbrowser.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Tor+bundles/installation&order=priority">bug
 tracker</a>)</h3>
 
 
 The Tor Browser Bundle is an easy-to-use portable package of Tor, Vidalia,
 and Firefox preconfigured to work together out of the box. This is actively
 being worked on by Erinn Clark.
 
 
 
 Project Ideas: 
 <a href="#auditTBB">Audit Tor Browser Bundles for data leaks</a> 
 <a href="#usabilityTesting">Usability testing of Tor</a>
 
 
 <a id="project-tails"></a>
 <h3><a href="https://tails.boum.org/">The Amnesic Incognito Live System</a> (<a
 href="http://git.immerda.ch/?p=amnesia.git;a=summary">code</a>, <a
 href="https://tails.boum.org/bugs/">bug
 tracker</a>)</h3>
 
 
 The Amnesic Incognito Live System is a live CD/USB distribution
 preconfigured so that everything is safely routed through Tor and leaves no
 trace on the local system. This is a merger of the Amnesia and <a
 href="http://www.anonymityanywhere.com/incognito/">Incognito</a> projects,
 and still under very active development.
 
 
 
 Project Ideas: 
 <a href="#tailsHiddenServicePetnames">Petname system for Tor hidden
 services</a> 
 <a href="#tailsServer">Tails server: Self-hosted services behind
 Tails-powered Tor hidden services</a>
 
 
 <a id="project-torsocks"></a>
 <h3><a href="http://code.google.com/p/torsocks/">Torsocks</a> (<a
 href="https://gitweb.torproject.org/torsocks.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torify&order=priority">bug
 tracker</a>)</h3>
 
 
 Utility for adapting other applications to work with Tor. Development has
 slowed and compatibility issues remain with some platforms, but it's
 otherwise feature complete.
 
 
 
 
 <a id="project-torouter"></a>
 <h3><a
 href="<wiki>doc/Torouter">Torouter</a> (<a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torouter&order=priority">bug
 tracker</a>)</h3>
 
 
 Project to provide an easy-to-use, embedded Tor instance for routers. This
 had high activity in late 2010, but has since been rather quiet.
 
 
 <a id="project-vidalia"></a>
 <h3><a href="<page projects/vidalia>">Vidalia</a> (<a
 href="https://gitweb.torproject.org/vidalia.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Vidalia&order=priority">bug
 tracker</a>)</h3>
 
 
 The most commonly used user interface for Tor. Matt Edman started the
 project in 2006 and brought it to its current stable state. Development
 slowed for several years, though Tomás Touceda has since taken a lead with
 pushing the project forward.
 
 
 
 Project Ideas: 
 <a href="#vidaliaStatusEventInterface">Tor Controller Status Event Interface for Vidalia</a> 
 <a href="#vidalia-hidden-service-panel">Torrc plugin and improved hidden service configuration panel</a>
 
 
 <a id="project-arm"></a>
 <h3><a href="http://www.atagar.com/arm/">Arm</a> (<a
 href="https://gitweb.torproject.org/arm.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=arm&order=priority">bug
 tracker</a>)</h3>
 
 
 Command-line monitor for Tor. This has been under very active development
 by its author, Damian Johnson, since early 2009 to make it a better
 general-purpose controller for *nix environments.
 
 
 
 
 <a id="project-orbot"></a>
 <h3><a href="https://guardianproject.info/apps/orbot/">Orbot</a> (<a
 href="https://gitweb.torproject.org/orbot.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Orbot&order=priority">bug
 tracker</a>)</h3>
 
 
 Provides Tor on the Android platform. This was under very active
 development up through Fall 2010, after which things have been quiet.
 
 
 
 
 <a id="project-torbutton"></a>
 <h3><a href="<page torbutton/index>">Torbutton</a> (<a
 href="https://gitweb.torproject.org/torbutton.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torbutton&order=priority">bug
 tracker</a>)</h3>
 
 
 Firefox addon that addresses many of the client-side threats to browsing
 the Internet anonymously. Mike has since continued to adapt it to new
 threats, updated versions of Firefox, and possibly <a
 href="https://blog.torproject.org/blog/google-chrome-incognito-mode-tor-and-fingerprinting">Chrome
 as well</a>.
 
 
 
 Project Ideas: 
 <a href="#torbuttonForThunderbird">Torbutton equivalent for Thunderbird</a>
 
 
 <a id="project-obfsproxy"></a>
 <h3><a href="https://gitweb.torproject.org/obfsproxy.git/tree/HEAD:/doc">Obfsproxy</a> (<a
 href="https://gitweb.torproject.org/obfsproxy.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Pluggable+transport&order=priority">bug
 tracker</a>)</h3>
 
 
 A proxy that shapes Tor traffic, making it harder for censors to detect and
 block Tor.
 
 
 
 Project Ideas: 
 <a href="#obfsproxy-new-transports">New and innovative pluggable transports</a> 
 <a href="#obfsproxy-scanning-measures">Defensive bridge active scanning measures</a> 
 <a href="#obfsproxy-fuzzer">Fuzzer for the Tor protocol</a>
 
 
 <a id="project-thandy"></a>
 <h3>Thandy (<a
 href="https://gitweb.torproject.org/thandy.git">code</a>)</h3>
 
 
 Updater for Tor. The project began in the Summer of 2008 but wasn't
 completed. Recently interest in it has been rekindled and many aspects of
 its design (including the language it'll be in) are currently in flux.
 
 
 <a id="project-ooni-probe"></a>
 <h3>Ooni Probe (<a
 href="https://gitweb.torproject.org/ooni-probe.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Ooni&order=priority">bug
 tracker</a>)</h3>
 
 
 Censorship scanner, checking your local connection for blocked or modified
 content.
 
 
 <a id="project-shadow"></a>
 <h3><a href="https://shadow.cs.umn.edu/">Shadow</a> (<a
 href="https://github.com/shadow">code</a>, <a
 href="https://github.com/shadow/shadow/issues">bug
 tracker</a>)</h3>
 
 
 Shadow is a discrete-event network simulator that runs the real
 Tor software as a plug-in. Shadow is open-source software that enables
 accurate, efficient, controlled, and repeatable Tor experimentation.
 
 
 <a id="project-torctl"></a>
 <h3>TorCtl (<a
 href="https://gitweb.torproject.org/pytorctl.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torctl&order=priority">bug
 tracker</a>)</h3>
 
 
 Python bindings and utilities for using the Tor control port. It has been
 stable for several years, with only minor revisions.
 
 
 <a id="project-stem"></a>
 <h3><a href="https://trac.torproject.org/projects/tor/wiki/doc/stem">Stem</a> (<a
 href="https://gitweb.torproject.org/stem.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Stem&order=priority">bug
 tracker</a>)</h3>
 
 
 Python controller library with a similar scope to TorCtl, but with better
 testing, documentation, and API. This project is not yet feature complete.
 
 
 
 Project Ideas: 
 <a href="#stemPathsupport">Stem PathSupport Capabilities</a>
 
 
 <a id="project-metrics"></a>
 <h3><a href="https://metrics.torproject.org/">Metrics</a> (code: <a
 href="https://gitweb.torproject.org/metrics-db.git">db</a>, <a
 href="https://gitweb.torproject.org/metrics-utils.git">utils</a>, <a
 href="https://gitweb.torproject.org/metrics-web.git">web</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Metrics&order=priority">bug
 tracker</a>)</h3>
 
 
 Processing and analytics of consensus data, provided to users via the
 metrics portal. This has been under active development for several years by
 Karsten Loesing.
 
 
 
 Project Ideas: 
 <a href="#metricsSearch">Searchable Tor descriptor and Metrics data archive</a> (Python/Django?)
 
 
 <a id="project-torstatus"></a>
 <h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/TorStatus">TorStatus</a> (<a
 href="https://gitweb.torproject.org/torstatus.git">code</a>)</h3>
 
 
 Portal providing an overview of the Tor network, and details on any of its
 current relays. Though very actively used, this project has been
 unmaintained for a long while. The <a
 href="https://svn.torproject.org/svn/torstatus/trunk/">original
 codebase</a> was written in PHP, and students from Wesleyan wrote the new
 Django counterpart.
 
 
 <a id="project-weather"></a>
 <h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/Weather">Weather</a> (<a
 href="https://gitweb.torproject.org/weather.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Tor+Weather&order=priority">bug
 tracker</a>)</h3>
 
 
 Provides automatic notification to subscribed relay operators when their
 relay's unreachable. This underwent a rewrite by the <a
 href="http://hfoss.wesleyan.edu/">Wesleyan HFOSS team</a>, which went live
 in early 2011.
 
 
 <a id="project-gettor"></a>
 <h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/EmailAutoResponder">GetTor</a> (<a
 href="https://gitweb.torproject.org/gettor.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=GetTor&order=priority">bug
 tracker</a>)</h3>
 
 
 E-mail autoresponder providing Tor's packages over SMTP. This has been
 relatively unchanged for quite a while.
 
 
 <a id="project-torcheck"></a>
 <h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/TorCheck">TorCheck</a> (<a
 href="https://svn.torproject.org/svn/check/trunk/">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Tor+Check&order=priority">bug
 tracker</a>)</h3>
 
 
 Provides a simple site for determining if the visitor is using Tor or not.
 This has been relatively unchanged for quite a while.
 
 
 <a id="project-bridgedb"></a>
 <h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/BridgeDB">BridgeDB</a> (<a
 href="https://gitweb.torproject.org/bridgedb.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=BridgeDB&order=priority">bug
 tracker</a>)</h3>
 
 
 Backend bridge distributor, handling the various pools they're distributed
 in. This was actively developed until Fall of 2010.
 
 
 <a id="project-torflow"></a>
 <h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/TorFlow">TorFlow</a> (<a
 href="https://gitweb.torproject.org/torflow.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torflow&order=priority">bug
 tracker</a>)</h3>
 
 
 Library and collection of services for actively monitoring the Tor network.
 These include the Bandwidth Scanners (measuring throughput of relays) and
 SoaT (scans for malicious or misconfigured exit nodes). SoaT was last
 actively developed in the Summer of 2010, and the Bandwidth Scanners a few
 months later. Both have been under active use since then, but development
 has stopped.
 
 
 <a id="project-torbel"></a>
 <h3><a
 href="https://trac.torproject.org/projects/tor/wiki/projects/TorBulkExitlist">TorBEL</a> (<a
 href="https://gitweb.torproject.org/tordnsel.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=TorDNSEL/TorBEL&order=priority">bug
 tracker</a>)</h3>
 
 
 The Tor Bulk Exitlist provides a method of identifying if IPs belong to
 exit nodes or not. This is a replacement for TorDNSEL which is a stable
 (though unmaintained) Haskell application for this purpose. The initial
 version of TorBEL was started in GSOC 2010 but since then the project has
 been inactive.
 
 
 <a id="Coding"></a>
 <a id="Summer"></a>
 <h2><a class="anchor" href="#Coding">Project Ideas</a></h2>
 
 
 You may find some of these projects to be good <a href="<page
 about/gsoc>">Google Summer of Code 2011</a> ideas. We have labelled each idea
 with how useful it would be to the overall Tor project (priority), how
 much work we expect it would be (effort level), how much clue you should
 start with (skill level), and which of our <a href="<page
 about/corepeople>">core developers</a> would be good mentors.
 If one or more of these ideas looks promising to you, please <a
 href="<page about/contact>">contact us</a> to discuss your plans rather than
 sending blind applications. You may also want to propose your own project
 idea &mdash; which often results in the best applications.
 
 
 <ol>
 
 <a id="auditTBB"></a>
 <li>
 Audit Tor Browser Bundles for data leaks
 
 Priority: High
 
 Effort Level: High
 
 Skill Level: Medium
 
 Likely Mentors: Jacob
 The Tor Browser Bundle incorporates Tor, Firefox, Polipo, and the Vidalia
 user interface (and optionally the <a href="http://pidgin.im/">Pidgin</a>
 Instant Messaging client). Components are pre-configured to operate in a
 secure way, and it has very few dependencies on the installed operating
 system. It has therefore become one of the most easy to use, and popular,
 ways to use Tor on Windows.
 This project is to identify all of the traces left behind by
 using a Tor Browser Bundle on Windows, Mac OS X, or Linux. Developing
 ways to stop, counter, or remove these traces is a final step.
 Students should be familiar with operating system analysis,
 application development on one or preferably all of Windows, Linux,
 and Mac OS X, and be comfortable with C/C++ and shell scripting.
 </li>
 
 <a id="firewallProbeTool"></a>
 <li>
 Develop a fully automatic firewall-probing system
 
 Priority: High
 
 Effort Level: Medium to High
 
 Skill Level: High
 
 Likely Mentors: Robert Ransom, Jacob
 We would like to have a fully automatic firewall-probing system for
 blocking systems with no long-term state (i.e. firewalls that can
 examine each connection, but do not change their behaviour for future
 connections based on the traffic they have seen).
 Ideally, volunteers would only need to set up one or more test servers,
 and run the probe client program on a publicly accessible computer
 behind the firewall.
 The test tool should:
 <ul>
 <li>generate packet captures on both ends (and send them out to the
 extent possible),</li>
 <li>cycle through all the SSL configurations we might want to test
 through a censorship device, and</li>
 <li>also test some other protocols to see whether they are allowed
 through the firewall (IMAP and other mail protocols, BitTorrent,
 DTLS, etc.).</li>
 </ul>
 </li>
 
 
 
 <a id="obfsproxy-new-transports"></a>
 <li>
 New and innovative pluggable transports
 
 Priority: High
 
 Effort Level: High
 
 Skill Level: High
 
 Likely Mentors: asn
 Not-very-smart transports like ROT13 and base64 are nice but not super
 interesting. Other ideas like bittorrent transports might be relevant,
 but you will have to provide security proofs on why they are harder to
 detect and block than other less-sophisticated transports.
 
 The whole point of this project, though, is to come up with new
 transports that we haven't already thought of. Be creative.
 
 Bonus points if your idea is interesting and still implementable
 through the summer period.
 
 More bonus points if it's implemented on top of obfsproxy, or if your
 implementation has a pluggable transport interface on top of it (as
 specified <a href="https://gitweb.torproject.org/torspec.git/blob/HEAD:/proposals/180-pluggable-transport.txt">here</a>).
 </li>
 
 <a id="obfsproxy-scanning-measures"></a>
 <li>
 Defensive bridge active scanning measures
 
 Priority: High
 
 Effort Level: High
 
 Skill Level: High
 
 Likely Mentors: asn
 Involves providing good answers to <a
 href="https://lists.torproject.org/pipermail/tor-dev/2011-November/003073.html">this
 thread</a> as well as concrete implementation plans for it.
 
 This also involves implementing proposals <a
 href="https://gitweb.torproject.org/torspec.git/blob/HEAD:/proposals/189-authorize-cell.txt">189</a>
 and <a
 href="https://gitweb.torproject.org/torspec.git/blob/HEAD:/proposals/190-shared-secret-bridge-authorization.txt">190</a>.
 </li>
 
 <a id="stemPathsupport"></a>
 <li>
 Stem PathSupport Capabilities
 
 Priority: High
 
 Effort Level: High
 
 Skill Level: Medium
 
 Likely Mentors: Damian (atagar)
 <a
 href="https://trac.torproject.org/projects/tor/wiki/doc/stem">Stem</a> is a
 python controller library for tor. Like it's predecessor, <a
 href="#project-torctl">TorCtl</a>, it uses tor's <a
 href="https://gitweb.torproject.org/torspec.git/blob/HEAD:/control-spec.txt">control
 protocol</a> to help developers program against the tor process, enabling
 them to build things similar to <a href="#project-vidalia">Vidalia</a> and
 <a href="#project-arm">arm</a>.
 
 While TorCtl provided a fine first draft for this sort of functionality,
 it has not proved to be extensible nor maintainable. Stem is a rewrite of
 TorCtl with a heavy focus on testing, documentation, and providing a
 developer friendly API.
 
 At the moment stem is still very much incomplete, missing several pieces
 of functionality that TorCtl provides. This is a project to fix that by
 porting TorCtl's <a
 href="https://gitweb.torproject.org/pytorctl.git/blob/HEAD:/PathSupport.py">PathSupport
 module</a> to stem, writing tests for it, and migrate a couple clients to
 use it.
 
 PathSupport provides applications with programmatic control over how
 tor's circuits are built, for instance letting you exit from particular
 relays. This is used by projects like <a href="#project-torbel">TorBEL</a>,
 <a href="#project-torflow">the Bandwidth Scanners, and SoaT</a>.
 
 This project can be broken into three parts...
 
 <ol style="list-style-type: decimal">
 <li>Look at PathSupport's clients to figure out how it is used and
 come up with the API that we will use for stem. Note that the goal if
 this project is not to simply copy PathSupport, but to make it
 better. This task would ideally be done as part of writing the GSoC
 application.</li>
 <li>Implement the PathSupport counterpart for stem. This should be
 done in an incremental fashion, writing the feature, tests, and going
 through a code review before moving on. I'll be pretty anal about making
 it as good as we can during these code reviews so plan for this to take a
 while. ;)</li>
 <li>The real test of the API that you've developed will come when we
 use it in some real applications. Try to migrate a TorCtl client or two
 to stem, filling in functionality that we're missing and improving our
 API as we discover issues. A particularly good client to start with would
 be TorBEL.</li>
 </ol>
 
 
 
 <a id="resistCensorship"></a>
 <li>
 Improving Tor's ability to resist censorship
 
 Priority: Medium to High
 
 Effort Level: Medium to High
 
 Skill Level: High
 
 Likely Mentors: Jake, Thomas
 The Tor 0.2.1.x series makes <a
 href="<svnprojects>design-paper/blocking.html">significant
 improvements</a> in resisting national and organizational censorship.
 But Tor still needs better mechanisms for some parts of its
 anti-censorship design.
 One huge category of work is adding features to our <a
 href="https://gitweb.torproject.org/bridgedb.git?a=tree">BridgeDB</a>
 service (Python). Tor aims to give out <a href="<page docs/bridges>">bridge
 relay addresses</a> to users that can't reach the Tor network
 directly, but there's an arms race between algorithms for distributing
 addresses and algorithms for gathering and blocking them. See <a
 href="<blog>bridge-distribution-strategies">our
 blog post on the topic</a> as an overview, and then look at <a
 href="https://lists.torproject.org/pipermail/tor-dev/2009-December/000666.html">Roger's
 or-dev post</a> from December 2009 for more recent thoughts &mdash; lots of
 design work remains.
 If you want to get more into the guts of Tor itself (C), a more minor problem
 we should address is that current Tors can only listen on a single
 address/port combination at a time. There's
 <a href="<specblob>proposals/118-multiple-orports.txt">a
 proposal to address this limitation</a> and allow clients to connect
 to any given Tor on multiple addresses and ports, but it needs more
 work.
 This project could involve a lot of research and design. One of the big
 challenges will be identifying and crafting approaches that can still
 resist an adversary even after the adversary knows the design, and
 then trading off censorship resistance with usability and
 robustness.
 </li>
 
 <a id="tailsHiddenServicePetnames"></a>
 <li>
 Petname system for Tor hidden services
 
 Priority: Medium
 
 Effort Level: High
 
 Skill Level: High
 
 Likely Mentors: ague
 Tor provides hidden services. These services are only reachable through
 Tor itself, and provide greater anonymity both for the providers of the
 service and for its users.
 One current downside of Tor hidden services is that they are addressed
 using 80-bit base32-encoded addresses such as "v2cbb2l4lsnpio4q.onion".
 These addresses are hard to remember; this makes them hard to use
 within amnesic environment like Tails.
 The project is to implement a petname system for Tor hidden services:
 a way for users or providers of Tor hidden services to add a simple
 'nickname' to a central database. Users could then query this central
 database to retrieve a full hidden service address by giving
 a nickname.
 Adding petnames to the database could be done using a web interface or
 automated fetch like those described in the <a
 href="https://gitweb.torproject.org/torspec.git/blob/HEAD:/proposals/ideas/xxx-onion-nyms.txt">&quot;.onion
 nym system&quot; proposal</a>.
 Querying the database could be done using a web interface, a REST API and
 a DNS interface.
 In order not to grow indefinitely, the software should make regular tests to
 see if hidden services are still reachable and, depending on the last time
 a nickname was accessed, cleanup the database as necessary.
 The software should allow a distributed, fault-tolerant setup.
 All nodes should have a synchronized copy of the database, should be
 ready to answer queries and should coordinate the tests for hidden
 service availability.
 The resulting codebase must be easy to deploy: it should not be hard to
 setup new databases.
 It is expected that the volunteer will be using Behaviour Driven
 Development methods. Either in Ruby using Cucumber and RSpec, or in
 Python using similar tools.
 </li>
 
 <a id="tailsServer"></a>
 <li>
 Tails server: Self-hosted services behind Tails-powered Tor hidden services
 
 Priority: Medium
 
 Effort Level: High
 
 Skill Level: Medium, but wide-scoped
 
 Likely Mentors: intrigeri, anonym
 Let's talk about group collaboration, communication and data sharing
 infrastructure, such as chat servers, wikis, or file repositories.
 Hosting such data and infrastructure in the cloud generally
 implies to trust the service providers not to disclose content, usage or
 users location information to third-parties. Hence, there are many threat
 models in which cloud hosting is not suitable.
 Tor partly answers the users location part; this is great, but
 content is left unprotected.
 There are two main ways to protect such content: either to encrypt it
 client-side (security by design), or to avoid putting it into
 untrusted hands in the first place.
 Cloud solutions that offer security by design are rare and generally
 not mature yet. The Tails server project is about exploring the
 other side of the alternative: avoiding to put private data into
 untrusted hands in the first place.
 This is made possible thanks to Tor hidden services, that allow users
 to offer location-hidden services, and make self-hosting possible in
 many threat models. Self-hosting has its own lot of problems, however,
 particularly in contexts where the physical security of the hosting
 place is not assured. Combining Tor hidden services with Tails'
 amnesia property and limited support for persistent encrypted data
 allows to protect content, to a great degree, even in such contexts.
 In short, setting up a new Tails server would be done by:
 
 <ol style="list-style-type: decimal">
 <li>Alice plugs a USB stick into a running desktop Tails system.</li>
 <li>Alice uses a GUI to easily configure the needed services.</li>
 <li>Alice unplugs the USB stick, that now contains encrypted services
 configuration and data storage space.</li>
 <li>Alice plugs that USB stick (and possibly a Tails Live CD) into the
 old laptop that was dedicated to run Tails server.</li>
 <li>Once booted, Alice enters the encryption passphrase either
 directly using the keyboard or through a web interface listening on the
 local network.</li>
 <li>Then, Bob can use the configured services once he gets a hold on
 the hidden service address. (The petname system for Tor hidden
 services project would be very complementary to this one, by the
 way.)</li>
 </ol>
 
 Tails server should content itself with hardware that is a bit old
 (such as a PIII-450 laptop with 256MB of RAM) and/or half broken (e.g.
 non-functional hard-disk, screen or keyboard).
 The challenges behind this project are:
 
 <ul>
 <li>Design and write the services configuration GUI [keywords: edit
 configuration files, upgrade between major Debian versions,
 debconf].</li>
 <li>How to create the hidden service key? [keywords: Vidalia, control
 protocol].</li>
 <li>Adapt the Tails boot process to allow switching to &quot;server
 mode&quot; when appropriate.</li>
 <li>Add support, to the Tails persistence setup process, for asking an
 encryption passphrase without X, and possibly with a broken keyboard
 and/or screen [keywords: local network, SSL/TLS?, certificate?].</li>
 </ul>
 
 This project can easily grow quite large, so the first task would
 probably be to clarify what it would need to get an initial (minimal
 but working) implementation ready to be shipped to users.
 This project does not require to be an expert in one specific field,
 but it requires to be experienced and at ease with a large scope of
 software development tools, processes, and operating system knowledge.
 Undertaking this project requires in-depth knowledge of Debian-like
 systems (self-test: do the "dpkg conffile" and "debconf preseeding"
 words sound new to your ear?); the Debian Live persistence system
 being written in shell, being at ease with robust shell scripting is
 a must; to end with, at least two pieces of software need to be
 written from scratch (a GUI and a webapp): the preferred languages for
 these tasks would be Python and Perl. Using Behaviour Driven
 Development methods to convey expectations and acceptance criteria
 would be most welcome.
 For more information see https://tails.boum.org/todo/server_edition/
 </li>
 
 <a id="geoIPUpgrade"></a>
 <li>
 Improve our GeoIP file format
 
 Priority: Medium
 
 Effort Level: Medium
 
 Skill Level: Medium to High
 
 Likely Mentors: Robert Ransom
 Currently, Tor bridges and relays read an entire IP-&gt;country database
 into memory from a text file during startup. We would like to
 distribute this database and store it on disk in a much more compact
 form, and perform IP-&gt;country lookups on it in its on-disk format if
 possible.
 We have <a href='https://trac.torproject.org/projects/tor/ticket/2506'>a
 sketch of a design</a> for a moderately optimized format for IPv4 GeoIP
 data; this project will involve both implementing the IPv4 format and
 designing and implementing a format for IPv6 GeoIP data.
 Since the core of this project is researching IPv6 GeoIP data and
 designing the IPv6 format, this is not likely to be a good GSoC
 project.
 </li>
 
 
 
 <a id="vidalia-hidden-service-panel"></a>
 <li>
 Torrc plugin and improved hidden service configuration panel
 
 Priority: Medium
 
 Effort Level: Medium
 
 Skill Level: Medium
 
 Likely Mentors: Tomás
 Vidalia's configuration handling has changed in the alpha branch. Now
 every Tor option is saved in the torrc file. With that change, the
 Hidden Service configuration panel was removed due to its specificity
 and its multiple bugs.
 
 The idea would be to provide the new Torrc class' functionality to the
 Plugin Engine and with that, create a better Hidden Service
 configuration panel as a plugin.
 
 A person undertaking this project should have good UI design, layout
 skills and some C++ development experience. Previous experience with Qt
 and Qt's Designer will be very helpful, but are not required. Javascript
 knowledge is a plus, but it shouldn't be a problem if the person
 complies with the previous requirements.
 </li>
 
 <a id="metricsSearch"></a>
 <li>
 Searchable Tor descriptor and Metrics data archive
 
 Priority: Medium
 
 Effort Level: Medium
 
 Skill Level: Medium
 
 Likely Mentors: Karsten
 The <a href="https://metrics.torproject.org/data.html">Metrics data archive</a> of Tor relay descriptors and other Tor-related network data has grown to over 100G in size, bz2-compressed. We have developed two search interfaces: the <a href="https://metrics.torproject.org/relay-search.html">relay search</a> finds relays by nickname, fingerprint, or IP address in a given month; <a href="https://metrics.torproject.org/exonerator-beta.html">ExoneraTor</a> finds whether a given IP address was a relay on a given day.
 
 We'd like to have a more general search application for Tor descriptors and metrics data. There are more <a href="https://metrics.torproject.org/formats.html">descriptor types</a> that we'd like to include in the search. The search application should handle most of them and understand some semantics like what's a timestamp, what's an IP address, and what's a link to another descriptor. Users should then be able to search for arbitrary strings or limit their search to given time periods or IP address ranges. Descriptors that reference other descriptors should contain links, and descriptors should be able to say from where they are linked. The goal is to make the archive easily browsable.
 
 The search application shall be separate from the metrics website and shouldn't rely on the metrics website codebase. The search application will contain hourly updated descriptor data from the metrics website via rsync. Programming language and database system are not specified yet, though there's a slight preference for Python/Django and Postgres for maintenance reasons. If there are good reasons to pick something else, e.g, some NoSQL variant or some search application framework, that's fine, too. Further requirements are that lookups should be really fast and that changes to the search application can be implemented in reasonable time.
 
 Applications for this project should come with a design of the proposed search application, ideally with a proof-of-concept based on a subset of the available data to show that it will be able to handle the 100G+ of data.
 
 
 
 
 
 <a id="torbuttonForThunderbird"></a>
 <li>
 Torbutton equivalent for Thunderbird
 
 Priority: Medium
 
 Effort Level: High
 
 Skill Level: High
 
 Likely Mentors: Mike
 
 We're hearing from an increasing number of users that they want to use
 Thunderbird with Tor. However, there are plenty of application-level
 concerns, for example, by default Thunderbird will put your hostname in
 the outgoing mail that it sends. At some point we should start a new
 push to build a Thunderbird extension similar to Torbutton.
 
 </li>
 
 <a id="usabilityTesting"></a>
 <li>
 Usability testing of Tor
 
 Priority: Medium
 
 Effort Level: Medium
 
 Skill Level: Low to Medium
 
 Likely Mentors: Andrew
 
 Especially the browser bundle, ideally amongst our target demographic.
 That would help a lot in knowing what needs to be done in terms of bug
 fixes or new features. We get this informally at the moment, but a more
 structured process would be better.
 
 
 
 Please note that since this isn't a coding project, it isn't suitable for
 Google Summer of Code.
 
 </li>
 
 
 
 <a id="vidaliaStatusEventInterface"></a>
 <li>
 Tor Controller Status Event Interface for Vidalia
 
 Priority: Medium
 
 Effort Level: Medium
 
 Skill Level: Low to Medium
 
 Likely Mentors: Tomás
 There are a number of status changes inside Tor of which the user may need
 to be informed. For example, if the user is trying to set up his Tor as a
 relay and Tor decides that its ports are not reachable from outside
 the user's network, we should alert the user. Currently, all the user
 gets is a couple of log messages in Vidalia's 'message log' window, which they
 likely never see since they don't receive a notification that something
 has gone wrong. Even if the user does actually look at the message log,
 most of the messages make little sense to the novice user.
 Tor has the ability to inform Vidalia of many such status
 changes, and we recently implemented support for a couple of these
 events. Still, there are many more status events which the user should
 be informed of, and we need a better UI for actually displaying them
 to the user.
 The goal of this project then is to design and implement a UI for
 displaying Tor status events to the user. For example, we might put a
 little badge on Vidalia's tray icon that alerts the user to new status
 events they should look at. Double-clicking the icon could bring up a
 dialog that summarizes recent status events in simple terms and maybe
 suggests a remedy for any negative events if they can be corrected by
 the user. Of course, this is just an example and one is free to
 suggest another approach.
 A person undertaking this project should have good UI design and layout
 skills and some C++ development experience. Previous experience with Qt and
 Qt's Designer will be very helpful, but are not required. Some
 English writing ability will also be useful, since this project will
 likely involve writing small amounts of help documentation that should
 be understandable by non-technical users. Bonus points for some graphic
 design/Photoshop fu, since we might want/need some shiny new icons too.
 </li>
 
 
 
 
 
 
 
 <a id="obfsproxy-fuzzer"></a>
 <li>
 Fuzzer for the Tor protocol
 
 Priority: Low to Medium
 
 Effort Level: Medium to High
 
 Skill Level: High
 
 Likely Mentors: asn
 Involves researching good and smart ways to fuzz stateful network
 protocols, and also implementing the fuzzer.
 
 We are mostly looking for a fuzzer that fuzzes the Tor protocol
 itself, and not the Tor directory protocol.
 
 Bonus points if it's extremely modular. Relevant research:
 
 <ul>
 <li>PROTOS - Security Testing of Protocol Implementations</li>
 <li>INTERSTATE: A Stateful Protocol Fuzzer for SIP</li>
 <li>Detecting Communication Protocol Security Flaws by Formal Fuzz
 Testing and Machine Learning</li>
 <li>SNOOZE: Toward a Stateful NetwOrk prOtocol fuzZE</li>
 <li>Michal Zalewski's &quot;bugger&quot;</li>
 <li>Also look at the concepts of &quot;model checking&quot; and
 &quot;symbolic execution&quot; to get inspired.</li>
 </ul>
 </li>
 
 
 
 <li>
 Bring up new ideas!
 
 Don't like any of these? Look at the <a
 href="/press/presskit/2008-12-19-roadmap-full.pdf">Tor development
 roadmap</a> for more ideas, or just try out Tor, Vidalia, and Torbutton,
 and find out what you think needs fixing.
 Some of the <a href="<spectree>proposals">current proposals</a>
 might also be short on developers.
 </li>
 
 </ol>
 
 <a id="OtherCoding"></a>
 <h2><a class="anchor" href="#OtherCoding">Other Coding and Design related ideas</a></h2>
 <ol>
 <li>Tor relays don't work well on Windows XP. On
 Windows, Tor uses the standard <tt>select()</tt> system
 call, which uses space in the non-page pool. This means
 that a medium sized Tor relay will empty the non-page pool, <a
 href="<wiki>doc/WindowsBufferProblems">causing
 havoc and system crashes</a>. We should probably be using overlapped IO
 instead. One solution would be to teach <a
 href="http://www.monkey.org/~provos/libevent/">libevent</a> how to use
 overlapped IO rather than select() on Windows, and then adapt Tor to
 the new libevent interface. Christian King made a
 <a href="https://svn.torproject.org/svn/libevent-urz/trunk/">good
 start</a> on this in the summer of 2007.</li>
 
 <li>We need to actually start building our <a href="<page
 docs/documentation>#DesignDoc">blocking-resistance design</a>. This involves
 fleshing out the design, modifying many different pieces of Tor, adapting
 <a href="<page projects/vidalia>">Vidalia</a> so it supports the
 new features, and planning for deployment.</li>
 
 <li>We need a flexible simulator framework for studying end-to-end
 traffic confirmation attacks. Many researchers have whipped up ad hoc
 simulators to support their intuition either that the attacks work
 really well or that some defense works great. Can we build a simulator
 that's clearly documented and open enough that everybody knows it's
 giving a reasonable answer? This will spur a lot of new research.
 See the entry <a href="#Research">below</a> on confirmation attacks for
 details on the research side of this task &mdash; who knows, when it's
 done maybe you can help write a paper or three also.</li>
 
 <li>Tor 0.1.1.x and later include support for hardware crypto
 accelerators via OpenSSL. It has been lightly tested and is
 possibly very buggy. We're looking for more rigorous testing,
 performance analysis, and optimally, code fixes to OpenSSL and
 Tor if needed.</li>
 
 <li>Perform a security analysis of Tor with <a
 href="https://secure.wikimedia.org/wikipedia/en/wiki/Fuzz_testing">"fuzz"</a>. Determine
 if there are good fuzzing libraries out there for what we want. Win fame by
 getting credit when we put out a new release because of you!</li>
 
 <li>Tor uses TCP for transport and TLS for link
 encryption. This is nice and simple, but it means all cells
 on a link are delayed when a single packet gets dropped, and
 it means we can only reasonably support TCP streams. We have a <a
 href="<page docs/faq>#TransportIPnotTCP">list
 of reasons why we haven't shifted to UDP transport</a>, but it would
 be great to see that list get shorter. We also have a proposed <a
 href="<specblob>proposals/100-tor-spec-udp.txt">specification
 for Tor and
 UDP</a> &mdash; please let us know what's wrong with it.</li>
 
 <li>We're not that far from having IPv6 support for destination addresses
 (at exit nodes). If you care strongly about IPv6, that's probably the
 first place to start.</li>
 
 <li>We need a way to generate the website diagrams (for example, the "How
 Tor Works" pictures on the <a href="<page about/overview>">overview page</a>
 from source, so we can translate them as UTF-8 text rather than edit
 them by hand with Gimp. We might want to
 integrate this as an wml file so translations are easy and images are
 generated in multiple languages whenever we build the website.</li>
 
 <li>How can we make the various LiveCD/USB systems easier
 to maintain, improve, and document? One example is <a
 href="https://tails.boum.org/">The Amnesic Incognito Live
 System</a>.
 </li>
 
 <li>
 Another anti-censorship project is to try to make Tor
 more scanning-resistant. Right now, an adversary can identify <a
 href="<specblob>proposals/125-bridges.txt">Tor bridges</a>
 just by trying to connect to them, following the Tor protocol,
 and seeing if they respond. To solve this, bridges could <a
 href="<svnprojects>design-paper/blocking.html#tth_sEc9.3">act like
 webservers</a> (HTTP or HTTPS) when contacted by port-scanning tools,
 and not act like bridges until the user provides a bridge-specific key.
 To start, check out Shane Pope's <a
 href="http://dl.dropbox.com/u/37735/index.html">thesis and prototype</a>.
 </li>
 
 </ol>
 
 <a id="Research"></a>
 <h2><a class="anchor" href="#Research">Research</a></h2>
 <ol>
 <li>The "end-to-end traffic confirmation attack":
 by watching traffic at Alice and at Bob, we can <a
 href="http://freehaven.net/anonbib/#danezis:pet2004">compare
 traffic signatures and become convinced that we're watching the same
 stream</a>. So far Tor accepts this as a fact of life and assumes this
 attack is trivial in all cases. First of all, is that actually true? How
 much traffic of what sort of distribution is needed before the adversary
 is confident he has won? Are there scenarios (e.g. not transmitting much)
 that slow down the attack? Do some traffic padding or traffic shaping
 schemes work better than others?</li>
 <li>A related question is: Does running a relay/bridge provide additional
 protection against these timing attacks? Can an external adversary that can't
 see inside TLS links still recognize individual streams reliably?
 Does the amount of traffic carried degrade this ability any? What if the
 client-relay deliberately delayed upstream relayed traffic to create a queue
 that could be used to mimic timings of client downstream traffic to make it
 look like it was also relayed? This same queue could also be used for masking
 timings in client upstream traffic with the techniques from <a
 href="http://www.freehaven.net/anonbib/#ShWa-Timing06">adaptive padding</a>,
 but without the need for additional traffic. Would such an interleaving of
 client upstream traffic obscure timings for external adversaries? Would the
 strategies need to be adjusted for asymmetric links? For example, on
 asymmetric links, is it actually possible to differentiate client traffic from
 natural bursts due to their asymmetric capacity? Or is it easier than
 symmetric links for some other reason?</li>
 <li>Repeat Murdoch and Danezis's <a
 href="http://www.cl.cam.ac.uk/~sjm217/projects/anon/#torta">attack from
 Oakland 05</a> on the current Tor network. See if you can learn why it
 works well on some nodes and not well on others. (My theory is that the
 fast nodes with spare capacity resist the attack better.) If that's true,
 then experiment with the RelayBandwidthRate and RelayBandwidthBurst
 options to run a relay that is used as a client while relaying the
 attacker's traffic: as we crank down the RelayBandwidthRate, does the
 attack get harder? What's the right ratio of RelayBandwidthRate to
 actually capacity? Or is it a ratio at all? While we're at it, does a
 much larger set of candidate relays increase the false positive rate
 or other complexity for the attack? (The Tor network is now almost two
 orders of magnitude larger than it was when they wrote their paper.) Be
 sure to read <a href="http://freehaven.net/anonbib/#clog-the-queue">Don't
 Clog the Queue</a> too.</li>
 <li>The "routing zones attack": most of the literature thinks of
 the network path between Alice and her entry node (and between the
 exit node and Bob) as a single link on some graph. In practice,
 though, the path traverses many autonomous systems (ASes), and <a
 href="http://freehaven.net/anonbib/#feamster:wpes2004">it's not uncommon
 that the same AS appears on both the entry path and the exit path</a>.
 Unfortunately, to accurately predict whether a given Alice, entry,
 exit, Bob quad will be dangerous, we need to download an entire Internet
 routing zone and perform expensive operations on it. Are there practical
 approximations, such as avoiding IP addresses in the same /8 network?</li>
 <li>Other research questions regarding geographic diversity consider
 the tradeoff between choosing an efficient circuit and choosing a random
 circuit. Look at Stephen Rollyson's <a
 href="http://swiki.cc.gatech.edu:8080/ugResearch/uploads/7/ImprovingTor.pdf">position
 paper</a> on how to discard particularly slow choices without hurting
 anonymity "too much". This line of reasoning needs more work and more
 thinking, but it looks very promising.</li>
 <li>Tor doesn't work very well when relays have asymmetric bandwidth
 (e.g. cable or DSL). Because Tor has separate TCP connections between
 each hop, if the incoming bytes are arriving just fine and the outgoing
 bytes are all getting dropped on the floor, the TCP push-back mechanisms
 don't really transmit this information back to the incoming streams.
 Perhaps Tor should detect when it's dropping a lot of outgoing packets,
 and rate-limit incoming streams to regulate this itself? I can imagine
 a build-up and drop-off scheme where we pick a conservative rate-limit,
 slowly increase it until we get lost packets, back off, repeat. We
 need somebody who's good with networks to simulate this and help design
 solutions; and/or we need to understand the extent of the performance
 degradation, and use this as motivation to reconsider UDP transport.</li>
 <li>A related topic is congestion control. Is our
 current design sufficient once we have heavy use? Maybe
 we should experiment with variable-sized windows rather
 than fixed-size windows? That seemed to go well in an <a
 href="http://www.psc.edu/networking/projects/hpn-ssh/theory.php">ssh
 throughput experiment</a>. We'll need to measure and tweak, and maybe
 overhaul if the results are good.</li>
 <li>Our censorship-resistance goals include preventing
 an attacker who's looking at Tor traffic on the wire from <a
 href="<svnprojects>design-paper/blocking.html#sec:network-fingerprint">distinguishing
 it from normal SSL traffic</a>. Obviously we can't achieve perfect
 steganography and still remain usable, but for a first step we'd like to
 block any attacks that can win by observing only a few packets. One of
 the remaining attacks we haven't examined much is that Tor cells are 512
 bytes, so the traffic on the wire may well be a multiple of 512 bytes.
 How much does the batching and overhead in TLS records blur this on the
 wire? Do different buffer flushing strategies in Tor affect this? Could
 a bit of padding help a lot, or is this an attack we must accept?</li>
 <li>Tor circuits are built one hop at a time, so in theory we have the
 ability to make some streams exit from the second hop, some from the
 third, and so on. This seems nice because it breaks up the set of exiting
 streams that a given relay can see. But if we want each stream to be safe,
 the "shortest" path should be at least 3 hops long by our current logic, so
 the rest will be even longer. We need to examine this performance / security
 tradeoff.</li>
 <li>It's not that hard to DoS Tor relays or directory authorities. Are client
 puzzles the right answer? What other practical approaches are there? Bonus
 if they're backward-compatible with the current Tor protocol.</li>
 <li>Programs like <a
 href="<page torbutton/index>">Torbutton</a> aim to hide
 your browser's UserAgent string by replacing it with a uniform answer for
 every Tor user. That way the attacker can't splinter Tor's anonymity set
 by looking at that header. It tries to pick a string that is commonly used
 by non-Tor users too, so it doesn't stand out. Question one: how badly
 do we hurt ourselves by periodically updating the version of Firefox
 that Torbutton claims to be? If we update it too often, we splinter the
 anonymity sets ourselves. If we don't update it often enough, then all the
 Tor users stand out because they claim to be running a quite old version
 of Firefox. The answer here probably depends on the Firefox versions seen
 in the wild. Question two: periodically people ask us to cycle through N
 UserAgent strings rather than stick with one. Does this approach help,
 hurt, or not matter? Consider: cookies and recognizing Torbutton users
 by their rotating UserAgents; malicious websites who only attack certain
 browsers; and whether the answers to question one impact this answer.
 </li>
 <li>How many bridge relays do you need to know to maintain
 reachability? We should measure the churn in our bridges. If there is
 lots of churn, are there ways to keep bridge users more likely to stay
 connected?
 </li>
 </ol>
 
 
 <a href="<page about/contact>">Let us know</a> if you've made progress on any
 of these!
 
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tor-webwml.git

Dropping the remaining orbot projects