getinvolved/en/volunteer.wml (840ea7a48) - 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>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

 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 with 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>Monitor some of our <a 
 href="https://lists.torproject.org/cgi-bin/mailman/listinfo">public mailing 
 lists</a>, like <a 
 href="https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-talk">tor-talk</a>, <a 
 href="https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays">tor-relays</a>, <a 
 href="https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-dev">tor-dev</a>, or <a 
 href="https://lists.torproject.org/cgi-bin/mailman/listinfo/tbb-dev">tbb-dev</a>, 
 and summarize noteworthy exchanges into articles for <a 
 href="https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-news">Tor 
 Weekly News</a>.</li>
 <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 around a theme, such as "Tor for Freedom!"</li>
 <li>Create a t-shirt design that incorporates "<a
 href="https://check.torproject.org/">Congratulations! You are using
 Tor!</a>" in any language.</li>
 <li>Spread the word about Tor at a symposium or conference and use these
 <a href="https://media.torproject.org/misc/2015-03-tor-brochure/">Tor
 brochures</a> in PDF and ODG format and translated to at least ten
 different languages as conversation starter.</li>
 </ol>

<!--
 <a id="gsoc"></a>
 <h2><a class="anchor" href="#gsoc">Google Summer of Code</a></h2>

Tor is also taking part in this year's <a
 href="https://www.google-melange.com/gsoc/homepage/google/gsoc2013">Google
 Summer of Code</a>! The criteria for this is a little different - either
 gender can apply but you need to be either <a
 href="https://www.google-melange.com/gsoc/document/show/gsoc_program/google/gsoc2013/help_page#2._Whos_eligible_to_participate_as_a">a
 present student or just graduated</a>.

As mentioned above if you're eligible for either program then please apply
 for both! Google Summer of Code is a far, far larger program for us than
 OPW so your chances of being applied that way are considerably better.

See our page for <a href="<page about/gsoc>">Google Summer of Code</a>
 for more information.
 
-->

<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.

For a presentation summarizing many of these projects see...

<div id="ecosystem_presentation">
 <a href="https://www.youtube.com/watch?v=fb6iqZcQsSg">Tor Ecosystem</a> (<a href="https://media.torproject.org/video/2013-11-t3am-damian-johnson.mp4">mp4</a>, <a href="https://svn.torproject.org/svn/projects/presentations/2013-11-t3am-tor-ecosystem.pdf">slides</a>)
 </div>

<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, athena, arma</td>
 </tr>

<tr>
 <td><a href="#project-torbrowser">Tor Browser</a></td>
 <td>Bundle</td>
 <td>Javascript, XUL, Scripting</td>
 <td>Heavy</td>
 <td>mikeperry, Pearl Crescent</td>
 </tr>

<tr>
 <td><a href="#project-httpseverywhere">HTTPS Everywhere</a></td>
 <td>Browser Add-on</td>
 <td>Javascript</td>
 <td>Heavy</td>
 <td>pde, mikeperry</td>
 </tr>

<tr>
 <td><a href="#project-nyx">Nyx</a></td>
 <td>User Interface</td>
 <td>Python, Curses</td>
 <td>Heavy</td>
 <td>atagar</td>
 </tr>

<tr>
 <td><a href="#project-orbot">Orbot</a></td>
 <td>User Interface</td>
 <td>Java</td>
 <td>Moderage</td>
 <td>n8fr8</td>
 </tr>

<tr>
 <td><a href="#project-tails">Tails</a></td>
 <td>OS image</td>
 <td>Sys Admin</td>
 <td>Heavy</td>
 <td><a href="https://tails.boum.org/">#tails</a></td>
 </tr>

<tr>
 <td><a href="#project-torramdisk">tor-ramdisk</a></td>
 <td>OS image</td>
 <td>Sys Admin</td>
 <td>Light</td>
 <td>blueness</td>
 </tr>

<tr>
 <td><a href="#project-torsocks">Torsocks</a></td>
 <td>Usability</td>
 <td>C</td>
 <td>Light</td>
 <td>David Goulet</td>
 </tr>

<tr>
 <td><a href="#project-torbirdy">TorBirdy</a></td>
 <td>Browser Add-on</td>
 <td>JavaScript</td>
 <td>Light</td>
 <td>sukhe</td>
 </tr>

<tr>
 <td><a href="#project-obfsproxy">Obfsproxy</a></td>
 <td>Client Add-on</td>
 <td>Python</td>
 <td>None</td>
 <td>asn</td>
 </tr>

<tr>
 <td><a href="#project-flash-proxy">Flash Proxy</a></td>
 <td>Client Add-on</td>
 <td>Python, JavaScript, Go</td>
 <td>Light</td>
 <td>dcf, infinity0, Arlo Breault</td>
 </tr>

<tr>
 <td><a href="#project-shadow">Shadow</a></td>
 <td>Simulator</td>
 <td>C, Python</td>
 <td>Heavy</td>
 <td>robgjansen</td>
 </tr>

<tr>
 <td><a href="#project-chutney">Chutney</a></td>
 <td>Simulator</td>
 <td>Python</td>
 <td>Light</td>
 <td>nickm</td>
 </tr>

<tr>
 <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-txtorcon">Txtorcon</a></td>
 <td>Library</td>
 <td>Python, Twisted</td>
 <td>Light</td>
 <td>meejah</td>
 </tr>

<tr>
 <td><a href="#project-tlsdate">Tlsdate</a></td>
 <td>Utility</td>
 <td>C</td>
 <td>None</td>
 <td>ioerror</td>
 </tr>

<tr>
 <td><a href="#project-metrics">Metrics</a></td>
 <td>Client Service</td>
 <td>Java</td>
 <td>Moderate</td>
 <td>karsten</td>
 </tr>

<tr>
 <td><a href="#project-atlas">Atlas</a></td>
 <td>Client Service</td>
 <td>JavaScript</td>
 <td>None</td>
 <td></td>
 </tr>

<tr>
 <td><a href="#project-globe">Globe</a></td>
 <td>Client Service</td>
 <td>JavaScript</td>
 <td>None</td>
 <td></td>
 </tr>

<tr>
 <td><a href="#project-compass">Compass</a></td>
 <td>Client Service</td>
 <td>Python</td>
 <td>None</td>
 <td></td>
 </tr>

<tr>
 <td><a href="#project-onionoo">Onionoo</a></td>
 <td>Backend Service</td>
 <td>Java</td>
 <td>Light</td>
 <td>karsten</td>
 </tr>

<tr>
 <td><a href="#project-exitmap">ExitMap</a></td>
 <td>Backend Service</td>
 <td>Python</td>
 <td>Light</td>
 <td>phw</td>
 </tr>

<tr>
 <td><a href="#project-doctor">DocTor</a></td>
 <td>Backend Service</td>
 <td>Python</td>
 <td>Light</td>
 <td>atagar</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>
 <td><a href="#project-gettor">GetTor</a></td>
 <td>Client Service</td>
 <td>Python</td>
 <td>Light</td>
 <td>ilv</td>
 </tr>

<tr>
 <td><a href="#project-torcheck">TorCheck</a></td>
 <td>Client Service</td>
 <td>Go</td>
 <td>None</td>
 <td>Arlo</td>
 </tr>

<tr>
 <td><a href="#project-bridgedb">BridgeDB</a></td>
 <td>Backend Service</td>
 <td>Python</td>
 <td>Light</td>
 <td>isis</td>
 </tr>

<tr>
 <td><a href="#project-ooni-probe">Ooni Probe</a></td>
 <td>Scanner</td>
 <td>Python</td>
 <td>Moderate</td>
 <td>hellais, aagbsn</td>
 </tr>

<tr>
 <td><a href="#project-torps">TorPS</a></td>
 <td>Backend Service</td>
 <td>Python</td>
 <td>None</td>
 <td>Aaron Johnson</td>
 </tr>

<tr>
 <td><a href="#project-torflow">TorFlow</a></td>
 <td>Backend Service</td>
 <td>Python</td>
 <td>None</td>
 <td>aagbsn</td>
 </tr>

<tr>
 <td>*<a href="#project-torbel">TorBEL</a></td>
 <td>Backend Service</td>
 <td>Python</td>
 <td>None</td>
 <td>Sebastian</td>
 </tr>

<tr>
 <td><a href="#project-tor2web">Tor2web</a></td>
 <td>Client Service</td>
 <td>Python</td>
 <td>Heavy</td>
 <td>evilaliv3, hellais</td>
 </tr>

<tr>
 <td><a href="#project-anonbib">Anonbib</a></td>
 <td>Website</td>
 <td>Python</td>
 <td>Light</td>
 <td>arma, nickm</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/report/12">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="#torCleanup">Tor Codebase Cleanup</a> 
 <a href="#improveTorTestCoverage">Improve test coverage in Tor</a> 
 <a href="#useMoreCores">Have the Tor daemon use more cores</a> 
 <a href="#improveHiddenServices">Help improve Tor hidden services</a> 
 <a href="#improvedDnsSupport">Improved DNS support for Tor</a>

<a id="project-torbrowser"></a>
 <h3><a href="<page projects/torbrowser>">Tor Browser</a> (<a
 href="https://gitweb.torproject.org/tor-browser.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&component=Tor+Launcher&component=Tor+Browser&component=Tor+bundles%2Finstallation&col=id&col=summary&col=status&col=owner&col=type&col=priority&col=milestone&order=priority">bug
 tracker</a>, <a href="https://www.torproject.org/projects/torbrowser/design/">design doc</a>)</h3>

Tor Browser is an easy-to-use, portable package of Tor, HTTPS-Everywhere, 
 NoScript, TorLauncher, Torbutton, and a Firefox fork, all preconfigured 
 to work together out of
 the box. The modified copy of Firefox aims to resolve the
 privacy and security issues in mainline version.

<a id="project-httpseverywhere"></a>
 <h3><a href="https://www.eff.org/https-everywhere">HTTPS Everywhere</a> (<a
 href="https://gitweb.torproject.org/https-everywhere.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/report/19">bug
 tracker</a>)</h3>

HTTPS Everywhere is a Firefox and Chrome extension that encrypts
 your communications with many major websites, making your browsing
 more secure.

<a id="project-nyx"></a>
 <h3><a href="https://www.atagar.com/arm/">Nyx</a> (<a
 href="https://gitweb.torproject.org/nyx.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>

Nyx (previously arm) is a terminal status monitor for Tor
 intended for command-line aficionados, ssh connections, and anyone with a
 tty terminal. This works much like top does for system usage, providing
 real time statistics for bandwidth, resource usage, connections, and quite
 a bit more.

<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. The project is under active 
 development, updates to latest Tor releases, and working to stay up to 
 date with all changes in Android and mobile threats.

<a id="project-tails"></a>
 <h3><a href="https://tails.boum.org/">The Amnesic Incognito Live System</a> (<a
 href="https://git-tails.immerda.ch/tails/">code</a>, <a
 href="https://labs.riseup.net/code/projects/tails">bug
 tracker</a>, <a href="https://tails.boum.org/doc">documentation</a>, <a
 href="https://tails.boum.org/contribute/design/">design</a>, <a
 href="https://tails.boum.org/contribute">contribute</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.

<a id="project-torramdisk"></a>
 <h3><a href="http://opensource.dyc.edu/tor-ramdisk">Tor-ramdisk</a> (<a
 href="https://gitweb.torproject.org/tor-ramdisk.git">code</a>, <a
 href="http://opensource.dyc.edu/tor-ramdisk-documentation">documentation</a>)</h3>

Tor-ramdisk is a uClibc-based micro Linux distribution whose sole
 purpose is to securely host a Tor server purely in RAM.

<a id="project-torsocks"></a>
 <h3>Torsocks (<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-torbirdy"></a>
 <h3>TorBirdy (<a
 href="https://github.com/ioerror/torbirdy">code</a>, <a
 href="https://trac.torproject.org/projects/tor/wiki/torbirdy/dev">bug
 tracker</a>)</h3>

TorBirdy is Torbutton for Thunderbird and related Mozilla mail clients.

Project Ideas: 
 <a href="#makeTorbirdyBetter">Make TorBirdy Better</a>

<a id="project-obfsproxy"></a>
 <h3><a href="<page projects/obfsproxy>">Obfsproxy</a> (<a
 href="https://gitweb.torproject.org/pluggable-transports/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. This has both a C and python implementation.

Project Ideas: 
 <a href="https://trac.torproject.org/projects/tor/wiki/doc/PluggableTransports#Helpneeded">Various coding tasks</a> 
 <a href="#betterPluggableTransports">Build Better Pluggable Transports</a>

<a id="project-flash-proxy"></a>
 <h3><a href="https://crypto.stanford.edu/flashproxy/">Flash Proxy</a> (<a
 href="https://gitweb.torproject.org/flashproxy.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_information&status=needs_review&status=needs_revision&status=new&status=reopened&component=Flashproxy">bug
 tracker</a>)</h3>

Pluggable transport using proxies running in web browsers to defeat
 address-based blocking.

<a id="project-chutney"></a>
 <h3>Chutney (<a href="https://gitweb.torproject.org/chutney.git">code</a>,
 <a href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_information&status=needs_review&status=needs_revision&status=new&status=reopened&component=Chutney">bug
 tracker</a>)</h3>

Integration test suite that spawns a local tor network, checking the
 interactions of its components.

<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.
 For another simulator, see <a
 href="http://crysp.uwaterloo.ca/software/exptor/">ExperimenTor</a>.

<a id="project-stem"></a>
 <h3><a href="https://stem.torproject.org/">Stem</a> (<a
 href="https://gitweb.torproject.org/stem.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/wiki/doc/stem/bugs">bug
 tracker</a>)</h3>

Python controller library for scripts and controller applications using
 Tor.

Project Ideas: 
 <a href="#txtorcon-stemIntegration">Txtorcon/Stem Integration</a>

<a id="project-txtorcon"></a>
 <h3><a href="https://txtorcon.readthedocs.org">Txtorcon</a> (<a
 href="https://github.com/meejah/txtorcon">code</a>, <a
 href="https://github.com/meejah/txtorcon/issues">bug tracker</a>)</h3>

Twisted-based asynchronous Tor control protocol implementation. Includes
 unit-tests, examples, state-tracking code and configuration abstraction.
 Used by OONI and APAF.

Project Ideas: 
 <a href="#txtorcon-stemIntegration">Txtorcon/Stem Integration</a>

<a id="project-tlsdate"></a>
 <h3>Tlsdate (<a href="https://github.com/ioerror/tlsdate">code</a>)</h3>

tlsdate: secure parasitic rdate replacement

tlsdate sets the local clock by securely connecting with TLS to remote
 servers and extracting the remote time out of the secure handshake. Unlike
 ntpdate, tlsdate uses TCP, for instance connecting to a remote HTTPS or TLS
 enabled service, and provides some protection against adversaries that try
 to feed you malicious time information.

<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-web.git">web</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. See also <a
 href="https://gitweb.torproject.org/torperf.git">TorPerf</a>.

<a id="project-atlas"></a>
 <h3><a href="https://atlas.torproject.org/">Atlas</a> (<a
 href="https://gitweb.torproject.org/atlas.git">code</a>)</h3>

Atlas is a web application to discover Tor relays and bridges. It provides
 useful information on how relays are configured along with graphics about
 their past usage.

This is the spiritual successor to <a
 href="https://gitweb.torproject.org/torstatus.git">TorStatus</a>, the <a
 href="https://svn.torproject.org/svn/torstatus/trunk/">original
 codebase</a> for which was written in PHP, and rewritten by students from
 Wesleyan as Django.

<a id="project-globe"></a>
 <h3><a href="http://globe.rndm.de/">Globe</a> (<a
 href="https://github.com/makepanic/globe">code</a>, <a
 href="https://github.com/makepanic/globe/issues">bug tracker</a>)</h3>

Globe is a web application that allows you to search for Tor relays and
 bridges. It gives you a detailed overview of properties and configurations
 of a relay or bridge.

<a id="project-compass"></a>
 <h3><a href="https://compass.torproject.org/">Compass</a> (<a
 href="https://gitweb.torproject.org/compass.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Compass&order=priority">bug
 tracker</a>)</h3>

Compass is a web and command line application that filters and
 aggregates the Tor relays based on various attributes.

<a id="project-onionoo"></a>
 <h3><a href="https://onionoo.torproject.org/">Onionoo</a> (<a
 href="https://gitweb.torproject.org/onionoo.git">code</a>,
 <a href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Onionoo&order=priority">bug tracker</a>)</h3>

Onionoo is a JSON based protocol to learn information about currently
 running Tor relays and bridges.

<a id="project-exitmap"></a>
 <h3><a href="http://www.cs.kau.se/philwint/spoiled_onions/">ExitMap</a> (<a
 href="https://github.com/NullHypothesis/exitmap">code</a>, <a
 href="https://github.com/NullHypothesis/exitmap/issues">bug tracker</a>)</h3>

Scanner for the Tor network by Philipp Winter to detect malicious and
 misconfigured exits. For more information about how it works see his <a
 href="http://www.cs.kau.se/philwint/spoiled_onions/pets2014.pdf">Spoiled
 Onions</a> research paper.

<a id="project-doctor"></a>
 <h3>DocTor (<a
 href="https://gitweb.torproject.org/doctor.git">code</a>, <a
 href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=DocTor&order=priority">bug
 tracker</a>)</h3>

DocTor is a notification service that monitors newly published descriptor
 information for issues. This is primarily a service to help the tor
 directory authority operators, but it also checks for a handful of other
 issues like sybil attacks.

<a id="project-weather"></a>
 <h3><a href="https://trac.torproject.org/projects/tor/wiki/org/roadmaps/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/org/roadmaps/GetTor">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/org/roadmaps/TorCheck">TorCheck</a> (<a
 href="https://gitweb.torproject.org/check.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+Check&order=priority">bug
 tracker</a>)</h3>

Site for determining if the visitor is using Tor or not.

<a id="project-bridgedb"></a>
 <h3><a href="https://trac.torproject.org/projects/tor/wiki/org/roadmaps/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-ooni-probe"></a>
 <h3><a href="https://ooni.torproject.org/">Ooni Probe</a> (<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.

Project Ideas: 
 <a href="#censorshipAnalyzer">Develop a Censorship Analyzer</a> 
 <a href="#ooniprobePcapsSupport">Add Support for Reporting Pcaps to OoniBackend and OoniProbe</a>

<a id="project-torps"></a>
 <h3>TorPS</a> (<a href="https://github.com/torps/torps">code</a>)</h3>

The Tor Path Simulator (TorPS) is a tool for efficiently simulating
 path selection in Tor. It chooses circuits and assigns user streams to
 those circuits in the same way that Tor does. TorPS is fast enough to
 perform thousands of simulations over periods of months.

<a id="project-torflow"></a>
 <h3><a href="https://trac.torproject.org/projects/tor/wiki/org/roadmaps/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://blog.torproject.org/blog/torbel-tor-bulk-exit-list-tools">TorBEL</a> (<a
 href="https://gitweb.torproject.org/torbel.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.

Tor2web allows Internet users to browse websites running in <a
 href="<page docs/hidden-services>">Tor hidden services</a>. It trades
 user anonymity for usability by allowing anonymous content to be
 distributed to non-anonymous users.

<a id="project-anonbib"></a>
 <h3><a
 href="http://freehaven.net/anonbib/">Anonymity Bibliography</a> (<a
 href="https://gitweb.torproject.org/anonbib.git">code</a>)</h3>

Anonbib is a list of important papers in the field of anonymity. It's
 also a set of scripts to generate the website from Latex (bibtex). If
 we're missing any important papers, please let us know!

<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 ideas for <a href="<page
 about/gsoc>">Google Summer of Code</a> and the <a
 href="https://live.gnome.org/OutreachProgramForWomen">Outreach Program for
 Women</a>. We have labelled each idea with 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="txtorcon-stemIntegration"></a>
 <li>
 Txtorcon/Stem Integration
 
 Effort Level: Medium
 
 Skill Level: Medium
 
 Likely Mentors: meejah, Damian (atagar)
 Txtorcon is a Twisted-based Python controller library, and Stem is a
 synchronous (threaded) one, also in Python. There is no need to have
 two implementations of (at least) the protocol parsing code. This
 project would entail eliminating duplication by leveraging Stem's
 parsing in txtorcon while keeping txtorcon's API the same (or at least
 close).
 Besides this you should identify some additional tasks to improve our
 controller space across these two libraries. Some ideas are...
 <ul>
 <li>Write a tutorial for <a
 href="https://stem.torproject.org/tutorials.html">stem's tutorial
 page</a> demonstrating cross txtorcon/stem usage.</li>
 <li>Expand the txtorcon API to include functionality of <a
 href="https://gitweb.torproject.org/stem.git/tree/stem/control.py">stem's
 controller</a> that would be of interest to twisted users. All additions
 should include tests!</li>
 <li>Come up with some ideas of your own! We'd love to discuss them with
 you.</li>
 </ul>
 This would very likely involve changes to both libraries, although
 most would be expected to be in txtorcon. meejah is available to
 mentor txtorcon changes, and Damian (atagar) can help with Stem.
 It would help if you're already familiar with event-based programming,
 bonus points if it's Twisted.
 </li>

<a id="torCleanup"></a>
 <li>
 Tor Codebase Cleanup
 
 Effort Level: Low to High, depending on subproject chosen
 
 Skill Level: Medium to High
 
 Likely Mentors: Nick (nickm), David (dgoulet)
 
 The Tor code is more than 10 years old in places, and we haven't always had
 enough time or wisdom to write things as well as we could have. Our unit
 test coverage is shamefully low, and the dependency graph of our modules is
 shamefully convoluted . We could use refactoring and unit tests! Please
 look through the Tor source code and look for ugly or tricky code or
 dependencies -- the uglier and trickier the better -- and think about how
 you could make the code look better, read better, and (subject to testing)
 work better.

If this is for a fun side-project, it would be great for you to work on
 anything that can be made better and more tested. For an internship-level
 position, we'd hope that you could find a number of particularly tricky or
 knotty piece of the code to clean up, and aim for resolving the ugliest
 problems, not necessarily the easiest.

For a big project here, it would be great to pick one of the major
 "submodules" of Tor -- path selection, node discovery, directory authority
 operations, directory service -- and refactor its interface completely, to
 minify and codify its points of contact with the rest of Tor.

As part of your application for this project please identify one of the
 thorniest Tor functions and submit a patch refactoring it to be better. If
 you find this to be difficult then this likely isn't the project for
 you.
 
 </li>

<a id="betterPluggableTransports"></a>
 <li>
 Build Better Pluggable Transports
 
 Effort Level: Medium to High
 
 Skill Level: Medium
 
 Likely Mentors: Ximin (infinity0)
 
 For Tor users in censored countries, we have a <a
 href="<page docs/pluggable-transports>">
 pluggable transports</a> framework that uses external programs to bypass
 censorship in different ways. Each of these have their own strengths and
 weaknesses.

We have deployed <a
 href="<page projects/obfsproxy>">obfsproxy</a>, 
 <a href="http://crypto.stanford.edu/flashproxy/">flashproxy</a>, 
 <a href="http://www.cs.kau.se/philwint/scramblesuit/">scramblesuit</a>, 
 <a href="https://trac.torproject.org/projects/tor/wiki/doc/meek">meek</a>,
 and <a href="https://fteproxy.org/about">FTE</a> bridges into the main 
 Tor Browser.</a>

There are several possible directions for this project. Ideas include:
 <ol>
 <li>Address gaps or weaknesses in our existing pluggable transports
 <ul>
 <li>Flashproxy: Add WebRTC support to traverse NATs.</li>
 <li>Flashproxy: Improve the facilitator's resistance against DoS
 and poisoning attacks.</li>
 </ul>
 </li>
 <li>Finish and release our pluggable transport combiner, that chains
 several transports together to take advantage of orthogonal types of
 blocking resistance.</li>
 <li>Improve the UX for selecting the appropriate pluggable transport in
 the new Tor Browser, whilst maintaining user security.</li>
 <li>Implement a new pluggable transport that resists blocking in a
 novel way.
 <ul>
 <li>Impersonate a voice-over-IP protocol</li>
 <li>Impersonate HTTP <a
 href="http://www.cs.utexas.edu/~amir/papers/parrot.pdf">sufficiently
 well</a> that traffic will go through a HTTP-only proxy</li>
 <li>Implement <a
 href="http://cacr.uwaterloo.ca/techreports/2011/cacr2011-21.pdf">scanning
 resistance</a></li>
 </ul>
 </li>
 </ol>

Applicants should be familiar with asynchronous/reactive programming, in
 particular the <a href="https://twistedmatrix.com/">Twisted framework</a>
 or something related. Most of the existing code is written in Python, with
 some parts in JavaScript and Go, so you should know at least one of these.
 You are invited to talk to us and ask questions, via our mailing lists
 or IRC. As part of your application, please contribute a patch that
 implements a small feature or fixes a bug related to this area, e.g. <a
 href="https://trac.torproject.org/projects/tor/query?status=!closed&component=Pluggable+transport">1</a>,
 <a href="https://trac.torproject.org/projects/tor/query?status=!closed&component=Obfsproxy">2</a>,
 <a href="https://trac.torproject.org/projects/tor/query?status=!closed&component=Flashproxy">3</a>.

<a id="profileUDPTransport"></a>
 <li>
 Profile UDP transport protocols
 
 Effort Level: Medium to High
 
 Skill Level: High
 
 Likely Mentors: Yawning
 
 There are <a
 href="https://research.torproject.org/techreports/datagram-comparison-2011-11-07.pdf">lots
 of options</a> as to how Tor could send its data over UDP rather than TCP,
 and some will likely perform significantly better than others. This project
 will evaluate these options, so as to decide which should be used in future
 versions of Tor. A first step will be to benchmark the various transport
 protocols being considered, in terms of performance and also code quality,
 including userspace TCP, <a
 href="https://github.com/bittorrent/libutp">&mu;TP</a>, <a
 href="http://en.wikipedia.org/wiki/Stream_Control_Transmission_Protocol">SCTP</a>
 and <a href="http://curvecp.org/">CurveCP</a>. Initially these transport
 protocols will be examined in isolation, but if the project progresses well
 one or more could be integrated in Tor.
 
 </li>

<a id="censorshipAnalyzer"></a>
 <li>
 Develop a Censorship Analyzer
 
 Effort Level: Medium
 
 Skill Level: Medium to High (depends on the implemented tests)
 
 Likely Mentors: Philipp (phw)
 
Tor is documented to be blocked in <a
href="https://censorshipwiki.torproject.org">several countries</a>. Analyzing
these censorship incidents can be a tedious task; especially without access to
machines inside the censoring networks. To make analysis easier, it would be
great to have a lightweight analysis tool which can be run by censored users.
This tool would conduct a number of networking tests and figure out if and how
Tor could be blocked. The tool's final report should then somehow make it back
to the Tor project.

The theory behind this tool is already <a
href="http://www.cs.kau.se/philwint/pdf/foci2013.pdf">documented
in a research paper</a>. What we now need is code! Implementing it would first
mean getting familiar with <a href="https://ooni.torproject.org">OONI</a> and
<a href="http://twistedmatrix.com/trac/">Twisted</a>. After that, the tool
should be implemented as a number of OONI-specific networking tests.

Applicants should be familiar with Python and asynchronous programming,
e.g., as it is used in Twisted. As part of your application for this
project please contribute a patch for a bug in <a
href="https://trac.torproject.org/projects/tor/query?status=!closed&component=Ooni">OONI</a>.
 
 </li>

<a id="makeTorbirdyBetter"></a>
 <li>
 Make TorBirdy Better
 
 Effort Level: High
 
 Skill Level: Medium
 
 Likely Mentors: Sukhbir Singh (sukhe), Jacob Appelbaum (ioerror)
 
TorBirdy is an extension that configures Thunderbird to make connections over
the Tor anonymity network. TorBirdy has been under development for quite a
while but there are two known leaks that prevent it from being used by a wider
audience. As part of this project, you will be working on plugging the known
leaks and implementing a HTTP proxy.

Part 1: There are two patches pending with Mozilla that will plug the two known
leaks in Thunderbird where the local time is disclosed through the date and the
message-ID header. As part of your project, you will work on getting these
patches finished/reimplemented and getting them merged with Mozilla. Please
look at tickets <a
href="https://trac.torproject.org/projects/tor/ticket/6314">#6314</a> and <a
href="https://trac.torproject.org/projects/tor/ticket/6315">#6315</a> for more
information.

Part 2: TorBirdy needs a HTTP proxy or a HTTP -&gt; SOCKS5 shim. Please look at
ticket <a href="https://trac.torproject.org/projects/tor/ticket/6958">#6958</a>
for more information. Note: this has to be done using JavaScript and not using
an external proxy.

If time permits and you are awesome enough to finish the above two tasks, you
will be working on the remaining TorBirdy tickets.

Applicants should be familiar with C++ and JavaScript. As part of your
application for this project, please submit code samples for previous C++ and
JavaScript projects that you have developed or point us to projects you have
been involved with (links to a public Git/GitHub repository preferred). Prior
extension development is a big plus and will be given preference during
application ranking.

You may contact the mentors on IRC for more information. (sukhe on #tor-dev, #tor on irc.oftc.net)
 
 </li>

<a id="ooniprobePcapsSupport"></a>
 <li>
 Add Support for Reporting Pcaps to OoniBackend and OoniProbe
 
 Effort Level: Medium
 
 Skill Level: Medium
 
 Likely Mentors: Arturo (hellais)
 
The feature should also add support for including only packet capture data that
is relevant to the test being run. This means that the pcap should not contain
all the data sniffed on the users machine, but only that which was generated
and intended to be received by ooniprobe.

This can probably be implemented by setting up a tun/tap device and routing all
the ooniprobe traffic through it and only capturing data sent and received from
that device. The task for the student will also be that of doing research into
what are possible strategies for doing this. <a
href="https://trac.torproject.org/projects/tor/ticket/7416">For more
information see ticket 7416.</a>
 
 </li>

<!--
 <a id="orbotVPN"></a>
 <li>
 Orbot Android VPN
 
 Effort Level: Medium
 
 Skill Level: High
 
 Likely Mentors: Nathan (n8fr8)
 
Android offers the ability for any application to establish a
VPNService through which all traffic on the device is sent. We want to
implement this type of service in order to route all traffic through
the Tor network. This is a feature that will be implemented directly
into Orbot: Tor for Android if successfully implemented.

The deliverables for the project will be a working Android VPN
implementation that routes traffic through Tor, and integration of VPN
code into the Orbot app. There must also be time made for reporting on
the project through blog posts, network auditing of tracking to ensure
leakage is not occurring.

Useful links and documentation to study:

<ul>
 <li><a href="https://gitweb.torproject.org/orbot.git">Orbot</a></li>
 <li><a href="http://developer.android.com/reference/android/net/VpnService.html">Android VPNService API</a></li>
 <li><a href="https://github.com/guardianproject/OrbotVPN">Existing work on Orbot VPN</a></li>
 </ul>

Applicant should have the ability to build Orbot application from
source using Android SDK and NDK tools. A solid understanding of IP
routing, iptables, netfilter and VPN protocols would also be very
helpful. The ability to use Wireshark or other network monitoring
software to test and verify solution is something that can be taught,
but if you already know how, bonus! Finally, understanding how the
exiting Tor software can be used with various transparent proxying
configurations is a good first step to understanding this problem.
 
 </li>
-->

<a id="improveTorTestCoverage"></a>
 <li>
 Improve test coverage in Tor
 
 Effort Level: Medium
 
 Skill Level: Medium
 
 Likely Mentors: Nick (nickm), David (dgoulet)
 
Right now, our unit test coverage with the tests we ship is around 30%
-- only 30% of the executable lines in our source are reached by the
unit tests. Improving this test coverage could make Tor development
much more reliable.

So we need better unit tests, and we need better integration tests too.

Improving unit tests would involve refactoring functions to be more
testable, and writing a bunch of unit tests.

Improving integration tests would involve refactoring and improving
the "chutney" program that launches a test tor network, and writing a
bunch of tests to see what works and what doesn't work on such a
network. It could also involve writing tests using the library "<a
href="https://stem.torproject.org/">stem</a>" to script individual clients on a
Chutney network.

To get a feel for how testing works in Tor today, download Tor and
Chutney, and make sure you can build Tor and use Chutney. See how the
unit tests work by skimming some of the test code in the src/test
subdirectory. Try computing test coverage (according to the
instructions in the doc/HACKING file.

Also, have a look at the one current integration test that works on
chutney today: it is a shell script distributed with Tor as
src/test/test-tor-network.sh . We probably don't want to have all of
our integration tests be written as shell scripts, but it's interesting
to see how one works.

If working on designs for an improved or refactored Chutney, watch out for <a
href="http://www.joelonsoftware.com/articles/fog0000000018.html">"archicture
astronautics"</a>: while it's important that we have a well-designed and
maintainable Chutney architecture, it wouldn't be very useful if a good
architecture were the only outcome here: we need tests too.

As part of the application process, please contribute a patch that makes
a non-trivial improvement to chutney, and/or include a new test for some
interesting Tor function. (Please pick a function that isn't completely
easy to test.)
 
 </li>

<a id="useMoreCores"></a>
 <li>
 Have the Tor daemon use more cores
 
 Effort Level: Medium
 
 Skill Level: Medium
 
 Likely Mentors: Nick (nickm), David (dgoulet)
 
Right now, if you run a busy Tor server on a multicore computer, most of
the cores are mostly unused. We have a "cpuworker" mechanism to move
expensive computations into worker threads, but that mechanism is
currently only used for a small fraction of our cryptography. Moving
more work into the worker threads could improve performance immensely.

So it would be great to parallelize our cryptography more in order to
better handle more cores. See
<a href="https://trac.torproject.org/projects/tor/wiki/org/projects/Tor/MultithreadedCrypto">MultithreadedCrypto</a>
for some background info, and
<a href="https://trac.torproject.org/projects/tor/ticket/7572">ticket 7572</a> for some subtickets
on our tracker.

(If you're reading through the code to see how it works today, you will
also want to have a look at the new implementation for cpuworkers
described in <a href="https://trac.torproject.org/projects/tor/ticket/9682">9682</a>.)

Completing the implementation of ticket #7572 --which would move our
circuit crypto onto separate threads-- could be a good summer project.
Alternatively, moving all of the signature generation and verification
code onto the cpuworkers could be fun. In either case, you will have
some important architectural decisions to make about how to minimize
shared data between the main thread and the workers, how to avoid
race conditions between them, and how to test it all to make sure it has
no hidden failure cases.

As part of the application process for this project, please contribute a
nontrivial patch to Tor -- ideally, one that will affect some part of
the codebase that you want to work on.
 
 </li>

<a id="improveHiddenServices"></a>
 <li>
 Help improve Tor hidden services
 
 Effort Level: Medium
 
 Skill Level: Medium
 
 Likely Mentors: Nick (nickm), David (dgoulet), George (asn)
 
We're working on a revamp of the entire Tor hidden service design to
improve the security and reliability of the hidden service system.

This is a big project: see
<a href="https://gitweb.torproject.org/torspec.git/tree/proposals/224-rend-spec-ng.txt">proposal
224</a> for the latest design. Are you interested in implementing some
part of that?

This is a very ambitious project, so we're deliberately not suggesting
particular sub-topics. If you're interested in participating, try to
read and understand the <a
href="https://gitweb.torproject.org/torspec.git/tree/rend-spec.txt">existing
design</a> and the design proposal for the new design, and then talk to
us about what part you want to work on.

<a id="improvedDnsSupport"></a>
 <li>
 Improved DNS support for Tor
 
 Effort Level: Medium
 
 Skill Level: Medium
 
 Likely Mentors: Nick (nickm), David (dgoulet)
 
Right now, you can only use Tor's DNS support to look up IPv4 and IPv6
addresses, and to fetch PTR records. But DNS can do so much more!

<a
href="https://gitweb.torproject.org/torspec.git/tree/proposals/219-expanded-dns.txt">Proposal
219</a> describes some new cell types that Tor could use to support
more types of DNS over Tor.

To see how Tor implements its existing DNS lookups, start by tracing the
the connection_exit_begin_resolve() function in src/or/connection_edge.c ,
and see how we pass these requests downwards through src/or/dns.c to the
underlying resolver. It's not too complicated, but there are some
tricky parts to understand.

<a id="ahmiaSearch"></a>
 <li>
 Ahmia - Hidden Service Search
 
 Effort Level: Medium
 
 Skill Level: Medium
 
 Likely Mentors: Juha Nurmi (numes), George (asn)
 
Ahmia is open-source search engine software for Tor hidden service deep dark web sites. You can test the running search engine at ahmia.fi. For more information see our <a href="https://blog.torproject.org/category/tags/ahmiafi">blog post about Ahmia's GSoC2014 development</a>.

Ahmia is a working search engine that indexes, searches, and catalogs content published on Tor Hidden Services. Furthermore, it is an environment to share meaningful insights, statistics, insights, and news about the Tor network itself. In this context, there is a lot of work to do.

The Ahmia web service is written using the Django web framework. As a result, the server-side language is Python. On the client-side, most of the pages are plain HTML. There are some pages that require JavaScript, but the search itself works without client-side JavaScript.

There are several possible directions for this project, including...

<ol>
 <li>Improving the search results (very important) 
 <ul>
 <li>Tweaking search algorithms</li>
 <li>Adjust Apache Solr</li>
 <li>Enrich the data that is used to rank the search results</li>
 </ul>
 </li>
 <li>Improving UX and UI (very important) 
 <ul>
 <li>Showing relevant knowledge</li>
 <li>Design the navigation and information architecture</li>
 <li>HTML5, CSS and Django development</li>
 </ul>
 </li>
 <li>Review code and infrastructure 
 <ul>
 <li>Review code and fix bugs</li>
 <li>Writing Django test cases</li>
 <li>Linux configurations, automatizations</li>
 </ul>
 </li>
 <li>Gather statistics over time and publish them 
 <ul>
 <li>Gather different kind of stats about Hidden Services</li>
 <li>Publish these stats using HTTP REST API</li>
 <li>Using this API show meaningful tables, charts and visualizations</li>
 </ul>
 </li>
 </ol>
 
 </li>

<a id="exitmap_improvements"></a>
 <li>
 Exitmap Improvements
 
 Effort Level: Medium
 
 Skill Level: Medium
 
 Likely Mentors: Philipp (phw)
 
The Tor Project makes use of the Python tool <a
href="https://gitweb.torproject.org/user/phw/exitmap.git/">Exitmap</a> to
systematically scan for malicious and misbehaving exit relays. Once such a
relay is found, it is assigned the BadExit flag which prevents clients from
selecting the relay as last hop in their circuit.

Exitmap supports scanning modules which implement a specific scan over
exit relays. Examples are the DNS module which checks for DNS poisoning
or the patching check module which looks out for tampered file
downloads.

This project is meant to extend exitmap in several ways. First, it
should be made fully autonomous. That means that exitmap should be able
to run in the background, periodically fetch new relay descriptors, and
have a smart algorithm which keeps scanning all exit relays
periodically. Second, exitmap should be able to emulate some user
interaction and dynamically "explore" the web in order to detect
tampering. Third, unit tests should be added for existing and new code
in order to make the code base more robust.
 
 </li>
<!--
 <a id="improveStegotorus"></a>
 <li>
 Improve Stegotorus
 
 Effort Level: Medium
 
 Skill Level: Medium
 
 Likely Mentors: vmon
 
Stegotorus is a fork of obfsproxy which helps developers to write more intelligent pluggable transports which can hide easier from deep packet inspector (DPI) system.

For example, Stegotorus is equipped with a "chopper module" which takes care of following aspects:

<ol>
 <li>It randomize the packet size so it is harder for the DPI system to detect the traffic base on the distribution of the packet size.</li>
 <li>It makes sure that it only handle as much (or as less) information as the transport module can handle.</li>
 <li>Chopper is equipped with it is own acknowledge/retransmit protocol. If the censor trying to disturb the connection by dropping or disturbing some of packets, it can recover the data by sending them many times.</li>
 </ol>

More importantly, Stegotorus is coming with its own HTTP transport module which obfuscates Tor or any other encrypted traffic in HTTP content such as Javascript code or images. HTTP transport module is also written in a way which new module developers can easily add new obfuscation modules for new contents or improve current obfuscation algorithms without the need of dealing with networking aspect of the problem.

Stegotorus is written in C++. you can find the latest code <a href="https://github.com/zackw/stegotorus/tree/tor-improve">here</a>.

In this regard, Stegotorus is offering one of the most complete and sophisticated platforms for writing stealthy pluggable transports.

If you know C++ and interested in Stegotorus and excited about battling censorship, there are many ways that you can contribute to Stegotorus. Here are few important tasks. Your proposal might contain a good number of them:

<ol>
 <li>Currently Stegotorus handshake is encrypted using the symmetric secret key of the Stegotorus bridge. However, we would like to implement a totally random handshake and considering that some transports suffer badly from "bandwidth shortage", our best choice currently is to implement <a href="http://elligator.cr.yp.to/">this algorithm</a>.</li>
 <li>Stegotorus defense against active probing is to authenticate the header of the received packet. If the authentication fails Stegotorus turns into a transparent proxy. The capability of Stegotorus as a transparent proxy needs improvement and further testing.</li>
 <li>Stegotorus has a new framework for writing Steg module. However some of the Steg modules (PDF, SWF and JS) are written in the old framework, we need to refactor their code in the new framework.</li>
 <li>As writting new Steg modules in python is easier and safer, it is desirable to write an Steg module interface for Stegotorus which can accept and interact with Steg modules written in python/cython.</li>
 <li>To make detection of anomalies in the traffic harder, Stegotorus hands a noise-to-signal ratio to each Steg modules. Steg modules' algorithms need to use more intelligent way of embedding to use this ratio.</li>
 <li>Stegotorus has several parameters to tweak its behavior. Currently all these parameters are given in command line. We would like to have a config file to store these parameters as an alternative method.</li>
 <li>The general security of the code needs to be reviewed and audited for buffer overflow, memory leak etc.</li>
 <li>Steg modules for new file format for the HTTP transport are always welcome to reflect the actual traffic of the Internet.</li>
 <li>Packaging Stegotorus for windows.</li>
 <li>There is a parallel efforts to improve Stegotorus at SRI. We would like to merge the useful feature developed by SRI in our branch of Stegotorus.</li>
 <li>Stegotorus needs to support SOCKS protocol to be able to receive the initial parameters from Tor through SOCKS handshake.</li>
 </ol>

You can find a list of open issues concerning Stegotorus <a href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_information&status=needs_review&status=needs_revision&status=new&status=reopened&component=Stegotorus&order=priority">here</a>.

You also can think of lots of other awesome creative ways of improving Stegotorus and include those in your proposal.
 
 </li>
-->

<!--
 <a id="newBridgedbDistributor"></a>
 <li>
 New BridgeDB Distributor
 
 Effort Level: Medium
 
 Skill Level: Medium to High
 
 Likely Mentors: isis, sysrqb
 
BridgeDB is a Twisted Python system which runs a number of servers, in order
to distribute Tor bridge relays to users in potentially censored regions. Each
of BridgeDB's Distributors uses some unique channel to communicate bridge
addresses to users, currently there is an <a href="https://bridges.torproject.org">
HTTPS Distributor</a>, and an Email Distributor. This project would involve
designing and creating a new Distributor for BridgeDB. Some ideas for new
Distributors:

<ul>
 <li>A Twitter bot which interacts with Chinese and Farsi speaking Twitter users through PMs.</li>
 <li>A distributor which uses XMPP+OTR to give bridges to users.</li>
 </ul>

It's helpful if you already have some knowledge of Twisted. As part of your
application, please submit a design for a Distributor, as well as supply a
patch for a ticket which demonstrates knowledge of Twisted and Python ―
preferably for BridgeDB, see the
<a href="https://trac.torproject.org/projects/tor/query?status=!closed&keywords=~bridgedb-gsoc-application">
'bridgedb-gsoc-application' Trac tag</a> for some examples of good tickets to
try, or contact isis or sysrqb on IRC to ask for ticket suggestions or advice.
 
 </li>
-->
<!--
 <a id=""></a>
 <li>
 
 
 Effort Level: Medium
 
 Skill Level: Medium
 
 Likely Mentors: Damian (atagar)

</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 and Tor Browser,
 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 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>Write a <a
 href="https://secure.wikimedia.org/wikipedia/en/wiki/Fuzz_testing">fuzzer</a>
 for Tor to discover security vulnerabilities. Determine if there
 are good fuzzing frameworks 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/index.php/hpn-ssh/638">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 docs/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!
 
 </div>
 
 <div id = "sidecol">
#include "side.wmi"
#include "info.wmi"
 </div>
 
</div>

#include <foot.wmi>

tor-webwml.git

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