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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 » </a>
<a href="<page getinvolved/volunteer>">Volunteer</a>
</div>
<div id="maincol">
<!-- PUT CONTENT AFTER THIS TAG -->
<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 — 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>
<p>Tor has <a href="<page getinvolved/open-positions>">two open positions</a>.
Please <a href="<page about/contact>">contact us</a> if you are qualified!</p>
<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="https://trac.torproject.org/projects/tor/wiki/TheOnionRouter/TorifyHOWTO">our
list of programs</a> that can be configured to use Tor.</li>
<li>We have a huge list of <a
href="https://trac.torproject.org/projects/tor/wiki/TheOnionRouter/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 <a
href="https://trac.torproject.org/projects/tor/wiki/CommunityLogos">community
logo</a> under a Creative Commons license that all can use and modify.</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="http://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>
<p>
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.
</p>
<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>Light</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>Heavy</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-thandy">Thandy</a></td>
<td>Updater</td>
<td>Python</td>
<td>Light</td>
<td>Sebastian, Erinn, nickm</td>
</tr>
<tr class="alt">
<td><a href="#project-torctl">TorCtl</a></td>
<td>Library</td>
<td>Python</td>
<td>Light</td>
<td>mikeperry</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>PHP</td>
<td>None</td>
<td></td>
</tr>
<tr>
<td><a href="#project-weather">Weather</a></td>
<td>Client Service</td>
<td>Python</td>
<td>Light</td>
<td>kaner</td>
</tr>
<tr class="alt">
<td><a href="#project-gettor">GetTor</a></td>
<td>Client Service</td>
<td>Python</td>
<td>Light</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>Moderate</td>
<td>kaner, nickm</td>
</tr>
<tr>
<td><a href="#project-torflow">TorFlow</a></td>
<td>Backend Service</td>
<td>Python</td>
<td>Light</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>
<sub>
* Project is still in an alpha state.
</sub>
<br /><br />
<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>
<p>
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.
</p>
<p>
<b>Project Ideas:</b><br />
<i><a href="#resistCensorship">Improving Tor's ability to resist
censorship</a></i><br />
<i><a href="#unitTesting">Improve our unit testing process</a></i><br />
<i><a href="#simulateSlowConnections">Simulator for slow Internet connections</a></i>
</p>
<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>
<p>
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.
</p>
<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>
<p>
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.
</p>
<p>
<b>Project Ideas:</b><br />
<i><a href="#auditTBB">Audit Tor Browser Bundles for data leaks</a></i><br />
<i><a href="#usabilityTesting">Usability testing of Tor</a></i>
</p>
<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>
<p>
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.
</p>
<p>
<b>Project Ideas:</b><br />
<i><a href="#tailsStartMenu">Custom GDM3 startup menu, aka.
tails-greeter</a></i><br />
<i><a href="#tailsMetadataAnonymizing">Meta-data anonymizing toolkit for
file publication</a></i><br />
<i><a href="#tailsDebianLive">Improve Debian Live support for
persistence</a></i>
</p>
<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>
<p>
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.
</p>
<p>
<b>Project Ideas:</b><br />
<i><a href="#torsocksForOSX">Make torsocks/dsocks work on OS X</a></i>
</p>
<a id="project-torouter"></a>
<h3><a
href="https://trac.torproject.org/projects/tor/wiki/TheOnionRouter/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>
<p>
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.
</p>
<a id="project-vidalia"></a>
<h3><a href="<page projects/vidalia>">Vidalia</a> (<a
href="https://svn.torproject.org/vidalia/vidalia/trunk/">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>
<p>
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.
</p>
<p>
<b>Project Ideas:</b><br />
<i><a href="#vidaliaStatusEventInterface">Tor Controller Status Event Interface for Vidalia</a></i><br />
<i><a href="#vidaliaNetworkMap">An Improved and More Usable Network Map in Vidalia</a></i>
</p>
<a id="project-arm"></a>
<h3><a href="http://www.atagar.com/arm/">Arm</a> (<a
href="https://svn.torproject.org/svn/arm/trunk/">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>
<p>
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.
</p>
<p>
<b>Project Ideas:</b><br />
<i><a href="#armClientMode">Client Mode Use Cases for Arm</a></i><br />
<i><a href="#armGui">GUI for Arm</a></i>
</p>
<a id="project-orbot"></a>
<h3><a href="https://guardianproject.info/apps/orbot/">Orbot</a> (<a
href="https://svn.torproject.org/svn/projects/android/trunk/Orbot/">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>
<p>
Provides Tor on the Android platform. This was under very active
development up through Fall 2010, after which things have been quiet.
</p>
<p>
<b>Project Ideas:</b><br />
<i><a href="#orbotDevelopment">More on Orbot & Android OS-specific development</a></i>
</p>
<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>
<p>
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>.
</p>
<p>
<b>Project Ideas:</b><br />
<i><a href="#torbuttonForThunderbird">Torbutton equivalent for Thunderbird</a></i>
</p>
<a id="project-thandy"></a>
<h3>Thandy (<a
href="https://gitweb.torproject.org/thandy.git">code</a>)</h3>
<p>
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.
</p>
<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>
<p>
Python bindings and utilities for using the Tor control port. It has been
stable for several years, with only minor revisions.
</p>
<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>
<p>
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.
</p>
<!--
<p>
<b>Project Ideas:</b><br />
<i><a href="#trackNetworkStatus">Help track the overall Tor Network status</a></i>
</p>
-->
<a id="project-torstatus"></a>
<h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/TorStatus">TorStatus</a> (<a
href="https://svn.torproject.org/svn/torstatus/trunk/">code</a>)</h3>
<p>
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.
</p>
<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>
<p>
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.
</p>
<a id="project-gettor"></a>
<h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/EmailAutoResponder">GetTor</a> (<a
href="https://svn.torproject.org/svn/projects/gettor/">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>
<p>
E-mail autoresponder providing Tor's packages over SMTP. This has been
relatively unchanged for quite a while.
</p>
<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>
<p>
Provides a simple site for determining if the visitor is using Tor or not.
This has been relatively unchanged for quite a while.
</p>
<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>
<p>
Backend bridge distributor, handling the various pools they're distributed
in. This was actively developed until Fall of 2010.
</p>
<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>
<p>
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.
</p>
<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>
<p>
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.
</p>
<!--
Copy and fill out the following for new projects:
<a id="project-"></a>
<h3><a href=""></a> (<a
href="">code</a>, <a
href="">bug
tracker</a>)</h3>
<p>
</p>
-->
<a id="Coding"></a>
<a id="Summer"></a>
<h2><a class="anchor" href="#Coding">Project Ideas</a></h2>
<p>
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 — which often results in the best applications.
</p>
<ol>
<a id="auditTBB"></a>
<li>
<b>Audit Tor Browser Bundles for data leaks</b>
<br>
Priority: <i>High</i>
<br>
Effort Level: <i>High</i>
<br>
Skill Level: <i>Medium</i>
<br>
Likely Mentors: <i>Steven, Erinn, Jacob, Andrew</i>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<p>If you would like to help extend or do security auditing for
TBB, please contact Erinn.</p>
</li>
<a id="firewallProbeTool"></a>
<li>
<b>Develop a fully automatic firewall-probing system</b>
<br>
Priority: <i>High</i>
<br>
Effort Level: <i>Medium to High</i>
<br>
Skill Level: <i>High</i>
<br>
Likely Mentors: <i>Robert Ransom, Nick, Jacob</i>
<p>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).</p>
<p>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.</p>
<p>The test tool should:</p>
<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="tailsStartMenu"></a>
<li>
<b>Custom GDM3 startup menu, aka. tails-greeter</b>
<br>
Priority: <i>High</i>
<br>
Effort Level: <i>Medium</i>
<br>
Skill Level: <i>Medium to High</i>
<br>
Likely Mentors: <i>intrigeri, anonym</i>
<p>Several major upcoming Tails features need to gather user input at
startup time: bridges support, persistence, MAC address anonymization,
etc.</p>
<p>Existing boot menus lack the graphical widgets and generally
user-friendliness needed. Hence it was decided to implement Tails startup
menu in GDM3: GDM3's default login/password prompt needs to be replaced
with a custom GTK+ application hereby named tails-greeter that allows the
user to provide any input necessary.</p>
<p>Anyone undertaking this project should be familiar with GNU/Linux and
application development; no other skill is required, apart of the ability
to quickly find practical answers in APIs and documentation for many
technologies she knows nothing about: this challenging coding project will
indeed involve getting familiar with some modern GNU/Linux Desktop
technologies such as D-Bus, GNOME and GConf. Python/GTK+ is probably the
best suited language for the task.</p>
<p>For more information see <a href="https://tails.boum.org/todo/boot_menu/">https://tails.boum.org/todo/boot_menu/</a></p>
</li>
<!--
<a id="trackNetworkStatus"></a>
<li>
<b>Help track the overall Tor Network status</b>
<br>
Priority: <i>Medium to High</i>
<br>
Effort Level: <i>Medium</i>
<br>
Skill Level: <i>Medium</i>
<br>
Likely Mentors: <i>Karsten, Roger</i>
<p>It would be great to set up an automated system for tracking network
health over time, graphing it, etc. Part of this project would involve
inventing better metrics for assessing network health and growth. Is the
average uptime of the network increasing? How many relays are qualifying
for Guard status this month compared to last month? What's the turnover
in terms of new relays showing up and relays shutting off? Periodically
people collect brief snapshots, but where it gets really interesting is
when we start tracking data points over time.</p>
<p>Data could be collected from the Tor Network Scanners in <a
href="https://svn.torproject.org/svn/torflow/trunk/README">TorFlow</a>, from
the server descriptors that each relay publishes, and from other
sources. Results over time could be integrated into one of the <a
href="https://torstatus.blutmagie.de/">Tor Status</a> web pages, or be
kept separate. Speaking of the Tor Status pages, take a look at Roger's
<a href="http://archives.seul.org/or/talk/Jan-2008/msg00300.html">Tor
Status wish list</a>.</p>
</li>
-->
<a id="resistCensorship"></a>
<li>
<b>Improving Tor's ability to resist censorship</b>
<br>
Priority: <i>Medium to High</i>
<br>
Effort Level: <i>Medium to High</i>
<br>
Skill Level: <i>High</i>
<br>
Likely Mentors: <i>Roger, Nick, Steven, Jake</i>
<p>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.</p>
<p>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="http://archives.seul.org/or/dev/Dec-2009/msg00000.html">Roger's
or-dev post</a> from December for more recent thoughts — lots of
design work remains.</p>
<p>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.</p>
<p>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.</p>
</li>
<a id="geoIPUpgrade"></a>
<li>
<b>Improve our GeoIP file format</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>Medium</i>
<br>
Skill Level: <i>Medium to High</i>
<br>
Likely Mentors: <i>Robert Ransom</i>
<p>Currently, Tor bridges and relays read an entire IP->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->country lookups on it in its on-disk format if
possible.</p>
<p>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.</p>
<!--<p>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.</p>-->
</li>
<a id="armClientMode"></a>
<li>
<b>Client Mode Use Cases for Arm</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>High</i>
<br>
Skill Level: <i>Medium</i>
<br>
Likely Mentors: <i>Damian</i>
<p><a href="<page projects/arm>">Arm</a> is a Tor command line status
monitor on *nix environments (Linux, Mac, and BSD). It functions much like
top does, giving a CLI overlay of Tor's bandwidth usage, connections,
configuration, log, etc. Thus far its design has been geared for Tor relay
operators. However, this doesn't need to be the case. This project would be
to expand and simplify arm to make it useful for Tor's client users
too.</p>
<p>This would include UI design, experimenting, and a lot of python
hacking. Here's some ideas for client functionality arm could provide:</p>
<ul>
<li>A panel for client connections, showing each hop of the user's
circuits with the ISP, country, and jurisdiction where those relays
reside. Other interesting information would be the circuit's latency, how
long its been around, and its possible exit ports. Some of this will be
pretty tricky and require some experimentation to figure out what
information can be fetched safely (for instance, scraping rdns and whois
lookups could give hints about a relay's ISP, but we'd need to do it on
all Tor relays to avoid leaking our connections to the resolver).</li>
<li>Options to let the user request new circuits (the "New
Identity" feature in Vidalia), select the exit country, etc.</li>
<li>A panel showing Internet application and if their connections are
being routed through Tor or not (giving a warning if there's leaks).</li>
<li>The status of the bridges we're configured to use (ie, are they up?).
This would include adding control port functionality to Tor for <a
href="https://trac.torproject.org/projects/tor/ticket/2068">ticket
2068</a>.</li>
<li>A one click option to set Tor to be a client, relay, or bridge. The
goal would be to make it trivial for users to voluntarily contribute to
the Tor network.</li>
<li>Menus as an alternative to hotkeys to make the interface more
intuitive and usable for beginners (<a
href="http://gnosis.cx/publish/programming/charming_python_6.html">example</a>).</li>
<li>Look at Vidalia and TorK for ideas and solicit input from the Tor community.</li>
</ul>
<p>
More information is available in the following sections of arm's dev notes: <a href="https://trac.torproject.org/projects/tor/wiki/projects/arm#ConnectionListingExpansion">Connection Listing Expansion</a>, <a href="https://trac.torproject.org/projects/tor/wiki/projects/arm#CircuitDetails">Circuit Details</a>, and <a href="https://trac.torproject.org/projects/tor/wiki/projects/arm#ClientModeUseCases">Client Mode Use Cases</a>
</p>
</li>
<a id="unitTesting"></a>
<li>
<b>Improve our unit testing process</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>Medium</i>
<br>
Skill Level: <i>Medium</i>
<br>
Likely Mentors: <i>Nick, Erinn</i>
<p>Tor needs to be tested far more thoroughly. This is a
multi-part effort. To start with, our unit test coverage should
rise substantially, especially in the areas outside the utility
functions. This will require significant refactoring of some parts
of Tor, in order to dissociate as much logic as possible from
globals.</p>
<p>Additionally, we need to automate our performance testing. We've got
buildbot to automate our regular integration and compile testing already
(though we need somebody to set it up on Windows),
but we need to get our network simulation tests (as built in <a
href="https://svn.torproject.org/svn/torflow/trunk/README">TorFlow</a>)
updated for more recent versions of Tor, and designed to launch a test
network either on a single machine, or across several, so we can test
changes in performance on machines in different roles automatically.</p>
</li>
<a id="orbotDevelopment"></a>
<li>
<b>More on Orbot & Android OS-specific development</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>High</i>
<br>
Skill Level: <i>Medium to High</i>
<br>
Likely Mentors: <i>Nathan, Jake</i>
<p><b>Android Java UI work:</b> Improved home screen to show better
statistics about data transferred (up/down), number of circuits
connected, quality of connection and so on. The "Tether Wifi"
Android application is a good model to follow in how it shows
a realtime count of bytes transferred as well as notifications
when wifi clients connect. In addition, better display/handling
of Tor system/error messages would also be very helpful. Finally,
the addition of a wizard or tutorial walkthrough for novice
users to explain to them exactly what is and what is not anonymized
or protected would greatly improve the likelihood they will use
Orbot correctly.</p>
<p><b>Android Java OS/Core app work:</b> Better system-wide
indication, either via the notification bar, "Toast" pop-up dialogs
or some other indicator, that an application's traffic is indeed
moving through Orbot/Tor. For instance, right now you need to
first go to a torcheck web service to ensure your browser is
routing via Tor. Orbot should be able to notify you that circuits
are being opened, used, etc. The aforementioned data transfer
tracker might provide this type of awareness as well.</p>
<p><b>Android Java Library/Community Outreach work:</b> We need
to package a simple library for use with third-party application
to easily enable them to support "Torification" on non-rooted
devices (i.e. w/o transparent proxying). This library should
include a wrapper for the Apache HTTPClient library, a utility
class for detecting the state of Orbot connectivity, and other
relevant/useful things an Android app might need to anonymize
itself. This work would include the creation of the library,
documentation, and sample code. Outreach or effort to implement
the library within other open-source apps would follow.</p>
<p><b>Android OS/C/Linux work:</b> The port of Tor to Android
is basically a straight cross-compile to Linux ARM. There has
been no work done in looking the optimization of Tor within a
mobile hardware environment, on the ARM processor or other
Android hardware, or on mobile networks. It should be noted,
that even without optimization, Tor is handling the mobile
network environment very well, automatically detecting change
in IP addresses, reconnecting circuits, etc. across switching
from 2G to 3G to Wifi, and so forth.</p>
</li>
<a id="simulateSlowConnections"></a>
<li>
<b>Simulator for slow Internet connections</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>Medium</i>
<br>
Skill Level: <i>Medium</i>
<br>
Likely Mentors: <i>Steven</i>
<p>
Many users of Tor have poor-quality Internet connections, giving low
bandwidth, high latency, and high packet loss/re-ordering. User
experience is that Tor reacts badly to these conditions, but it is
difficult to improve the situation without being able to repeat the
problems in the lab.
</p>
<p>
This project would be to build a simulation environment which
replicates the poor connectivity so that the effect on Tor performance
can be measured. Other components would be a testing utility to
establish what are the properties of connections available, and to
measure the effect of performance-improving modifications to Tor.
</p>
<p>
The tools used would be up to the student, but dummynet (for FreeBSD)
and nistnet (for Linux) are two potential components on which this
project could be built. Students should be experienced with network
programming/debugging and TCP/IP, and preferably familiar with C and a
scripting language.
</p>
</li>
<a id="torbuttonForThunderbird"></a>
<li>
<b>Torbutton equivalent for Thunderbird</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>High</i>
<br>
Skill Level: <i>High</i>
<br>
Likely Mentors: <i>Mike</i>
<p>
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.
</p>
</li>
<a id="usabilityTesting"></a>
<li>
<b>Usability testing of Tor</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>Medium</i>
<br>
Skill Level: <i>Low to Medium</i>
<br>
Likely Mentors: <i>Andrew</i>
<p>
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.
</p>
<p>
Please note that since this isn't a coding project, it isn't suitable for
Google Summer of Code.
</p>
</li>
<!-- <a id="authenticatingIrcProxy"></a>
<li>
<b>An authenticating IRC proxy</b>
<br>
Priority: <i>Low</i>
<br>
Effort Level: <i>Medium to High</i>
<br>
Skill Level: <i>Medium to High</i>
<br>
Likely Mentors: <i>Sebastian, Peter, Roger</i>
<p>
The world needs an authenticating irc proxy. As we're periodically
reminded from the Penny Arcade web comic, "Internet user + anonymity =
jerk". With respect to websites we're actually doing ok, since websites
can make their users log in and use other application-level authentication
approaches. But IRC servers are much worse off, because most IRC server
code is poorly written: hard to maintain, and harder to modify. Many
IRC networks now block connections from Tor, and we're basically down to
two holdouts (OFTC and Freenode). This state of affairs means that a lot
of people around the world are thinking "I told you so" about anonymity
online, when in fact the problem is simply lack of technology to make the
problem manageable. We need some way to let the IRC networks distinguish
which users have developed a reputation as not being jerks, so they can
treat the two groups separately. There are some really cool research
designs like <a href="http://www.cs.dartmouth.edu/~nymble/">Nymble</a>,
which aim to let websites blacklist users without needing to learn who
they are. But Nymble is designed around web interactions. We need to
build the glue around the IRC protocol that would let us plug in a project
like Nymble (or a simpler one to start, as a proof-of-concept). One way
to do that would be to build an IRC proxy that knows how to hear from
IRC clients, knows how to talk to IRC servers, and has an additional
layer that requires the users to authenticate. Some work on this has
begun by other volunteers, see their progress at <a
href="https://github.com/anonirc/orc">https://github.com/anonirc/orc</a>.
</p>
</li>
-->
<a id="tailsMetadataAnonymizing"></a>
<li>
<b>Meta-data anonymizing toolkit for file publication</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>Low to Medium</i>
<br>
Skill Level: <i>Low to Medium</i>
<br>
Likely Mentors: <i>intrigeri, anonym</i>
<p>Tor helps greatly in publishing files anonymously. However, much personal
information can be enclosed *inside* such published files' meta-data: GPS
coordinates, author's name and so on. Anyone who wants to anonymously
publish a file can thus far too easily de-anonymize herself.</p>
<p>A set of tools allowing users to easily inspect and clean up meta-data in files
would benefit Tor users, and would e.g. be shipped in Tails.</p>
<p>A graphical user interface is a must, but library and command-line
interfaces are most welcome so that future work can add support for
cleaning published files to various publishing tools, such as desktop
social networking clients and Web content management systems.</p>
<p>This project mostly consists of writing glue between the many existing
tools and libraries that provide read/write access to files' meta-data. An
extensible program design would probably be the best bet, so that support
for other kinds of files can easily be added later.</p>
<p>The meta-data cleaning toolkit would run at least on GNU/Linux;
additional Windows and/or Mac OS X support would be welcome. The tools used
would be up to the students. The detailed specification is ready and will
be published soon.</p>
<a id="tailsDebianLive"></a>
<li>
<b>Improve Debian Live support for persistence</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>Medium</i>
<br>
Skill Level: <i>Low to Medium</i>
<br>
Likely Mentors: <i>intrigeri, anonym</i>
<p>Data persistence is a somewhat tricky topic in a Live system context,
especially one such as Tails, which is explicitly designed to avoid
leaving any trace of its use.</p>
<p>Some real-life use cases, however, require some kind of data
persistence. To start with, Tails should (carefully) support persistence of
application-specific configurations (e.g. GnuPG keyring) and of a user
arbitrary data store. Note that persistence in Tails will always be opt-in
and require encrypted storage.</p>
<p>The backend work consists of improving Debian Live's existing
persistence features to make them suit the specific context of Tails. A trust
relationship is already established with upstream who is happy to merge our
changes. The codebase is not that small and much refactoring is needed, so
this really is a programming project rather than a fire'n'forget shell
script hack contest.</p>
<p>Anyone undertaking this project must be familiar with GNU/Linux, and
preferably with Debian. Being able to (quickly learn to) write clean and
safe programs in shell is also needed.</p>
<p>For more information, see <a href="https://tails.boum.org/todo/persistence/">https://tails.boum.org/todo/persistence/</a>.</p>
<a id="torsocksForOSX"></a>
<li>
<b>Make torsocks/dsocks work on OS X</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>Medium</i>
<br>
Skill Level: <i>Medium</i>
<br>
Likely Mentors: <i>Robert Hogan</i>
<p>
<a href="https://code.google.com/p/torsocks/">Torsocks</a> and <a
href="https://code.google.com/p/dsocks/">dsocks</a> are wrappers that will
run applications, intercept their outgoing network connections, and push
those connections through Tor. The goal is to handle applications that
don't support proxies (or don't supporting them well). To get it right,
they need to intercept many system calls. The syscalls you need to
intercept on Linux differ dramatically from those on BSD. So Torsocks
works fine on Linux, dsocks works ok on BSD (though it may be less
maintained and thus might miss more syscalls), and nothing works well
on both. First, we should patch dsocks to use Tor's <i>mapaddress</i>
commands from the controller interface, so we don't waste a whole
round-trip inside Tor doing the resolve before connecting. Second,
we should make our <i>torify</i> script detect which of torsocks or
dsocks is installed, and call them appropriately. This probably means
unifying their interfaces, and might involve sharing code between them
or discarding one entirely.
</p>
</li>
<a id="vidaliaStatusEventInterface"></a>
<li>
<b>Tor Controller Status Event Interface for Vidalia</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>Medium</i>
<br>
Skill Level: <i>Low to Medium</i>
<br>
Likely Mentors: <i>Tomás</i>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<p>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.</p>
</li>
<a id="vidaliaNetworkMap"></a>
<li>
<b>An Improved and More Usable Network Map in Vidalia</b>
<br>
Priority: <i>Low to Medium</i>
<br>
Effort Level: <i>Medium</i>
<br>
Skill Level: <i>Medium</i>
<br>
Likely Mentors: <i>Tomás</i>
<p>
One of Vidalia's existing features is a network map that shows the user
the approximate geographic location of relays in the Tor network and
plots the paths the user's traffic takes as it is tunneled through the
Tor network. The map is currently not very interactive and has rather
poor graphics. Instead, we implemented KDE's Marble widget such
that it gives us a better quality map and enables improved interactivity,
such as allowing the user to click on individual relays or circuits to
display additional information. We want to add the ability
for users to click on a particular relay or a country containing one or
more Tor exit relays and say, "I want my connections to exit
from here."
</p>
<p>
This project will first involve getting familiar with Vidalia
and the Marble widget's API. One will then integrate the widget
into Vidalia and customize Marble to be better suited for our application,
such as making circuits clickable, storing cached map data in Vidalia's
own data directory, and customizing some of the widget's dialogs.
</p>
<p>
A person undertaking this project should have good C++ development
experience. Previous experience with Qt and CMake is helpful, but not
required.
</p>
</li>
<a id="armGui"></a>
<li>
<b>GUI for Arm</b>
<br>
Priority: <i>Low</i>
<br>
Effort Level: <i>High</i>
<br>
Skill Level: <i>Medium</i>
<br>
Likely Mentors: <i>Damian</i>
<p>
Arm has several unique features, some of the most interesting being its
connection listing (correlating netstat results against the Tor consensus)
and configuration editor (a quick method for editing Tor's config, with
information pulled from the control port and man page). However, since arm
is a command line controller it's of limited appeal to certain sets of
users. This project would be to build a GTK or Qt frontend for the
controller, providing similar features set but with a windowed interface.
</p>
<p>
The vast majority of arm's more interesting functionality lies in its
backend <a
href="https://svn.torproject.org/svn/arm/trunk/src/util/">utilities</a>, so
there should be little to no work decoupling the CLI from its backend.
Instead, this project would mostly be UI hacking and experimentation,
trying different interfaces to find something that's elegant and simple,
but matches the information found in the current terminal application.
</p>
</li>
<!--
<li>
<b>Help with independent Tor client implementations</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>High</i>
<br>
Skill Level: <i>Medium to High</i>
<br>
Likely Mentors: <i>Bruce, Nathan</i>
<p>Others are currently working on Tor clients for Java, Android, and Maemo
environments. The first step is to get a handle on the current state of
the project in which you are interested in helping; <a
href="https://github.com/brl/JTor">Tor for Java</a>,
<a href="https://svn.torproject.org/svn/projects/android/trunk/">Android/Orbot</a>,
or <a href="<page docs/N900>">Tor for Maemo</a>. Check out the
repository and familiarize yourself
with the source code. Further, support for requesting or even providing
Tor hidden services would be neat, but not required.</p>
<p>A prospective developer should be able to understand and write new Java
code, including a Java cryptography API. Being able to read C code would be helpful,
too. One should be willing to read the existing documentation,
implement code based on it, and refine the documentation
when things are underdocumented. This project is mostly about coding and
to a small degree about design.</p>
</li>
-->
<!--
<li>
<b>Improvements for Tor+Vidalia interaction on Linux/Unix platforms</b>
<br>
Priority: <i>Medium</i>
<br>
Effort Level: <i>Medium</i>
<br>
Skill Level: <i>Medium</i>
<br>
Likely Mentors: <i>Erinn, Peter</i>
<p>
Vidalia currently doesn't play nicely with Tor on Linux and Unix platforms.
Currently, on Debian and Ubuntu, there is a configuration mechanism which
allows Vidalia to override Tor's ability to start on boot (by sourcing
<code>/etc/default/tor.vidalia</code> which sets <code>RUN_DAEMON=no</code> at the user's
request), but full implementation of <a href="<specblob>control-spec.txt">ControlPort</a>
communication is still required.
</p>
<p>
A better solution on Linux and Unix platforms would be to use Tor's
ControlSocket, which allows Vidalia to talk to Tor via a Unix domain socket,
and could possibly be enabled by default in Tor's distribution packages.
Vidalia can then authenticate to Tor using filesystem-based (cookie)
authentication if the user running Vidalia is also in the distribution-specific
tor group.
</p>
<p>
This project will first involve adding support for Tor's ControlSocket to
Vidalia. The student will then develop and test this support on various
distributions to make sure it behaves in a predictable and consistent manner on
all of them.
</p>
<p>
The next challenge would be to find an intuitive and usable way for Vidalia to be
able to change Tor's configuration (torrc) even though it is located in
<code>/etc/tor/torrc</code> and thus immutable. In Debian and Ubuntu we handle
this with the aforementioned <code>/etc/default/tor.vidalia</code> but this
functionality could (or should) be less distribution-specific.
</p>
<p>
The best idea we've come up with so far is to feed Tor a new configuration via
the ControlSocket when Vidalia starts, but that's bad because if the user is not
using the latest Debian/Ubuntu packages, they may not have disabled Tor's
ability to run on boot and will end up with a configuration that is different
from what they want. The second best idea we've come up with is for Vidalia to
write out a temporary torrc file and ask the user to manually move it to
<code>/etc/tor/torrc</code>, but that's bad because users shouldn't have to
mess with files directly.
</p>
<p>
A person undertaking this project should have prior knowledge of various Linux
distributions and their packaging mechanisms as well as some C++ development
experience. Previous experience with Qt is helpful, but not required.
</p>
</li>
-->
<li>
<b>Bring up new ideas!</b>
<br>
Don't like any of these? Look at the <a
href="<gitblob>doc/roadmaps/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="https://trac.torproject.org/projects/tor/wiki/TheOnionRouter/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 — 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> — 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>
<p>
<a href="<page about/contact>">Let us know</a> if you've made progress on any
of these!
</p>
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