tor-webwml.git

en/volunteer.wml    1) ## translation metadata

en/volunteer.wml    2) # Revision: $Revision$

volunteer.html      3) 

en/volunteer.wml    4) #include "head.wmi" TITLE="Tor: Volunteer"

volunteer.html      5) 
volunteer.html      6) <div class="main-column">
volunteer.html      7) 
volunteer.html      8) <!-- PUT CONTENT AFTER THIS TAG -->

en/volunteer.wml    9) <h2>Three things everyone can do now:</h2>

volunteer.html     10) <ol>

en/volunteer.wml   11) <li>Please consider <a href="<page docs/tor-doc-relay>">running
en/volunteer.wml   12) a relay</a> to help the Tor network grow.</li>
en/volunteer.wml   13) <li>Tell your friends! Get them to run relays. Get them to run hidden

volunteer.html     14) services. Get them to tell their friends.</li>

en/volunteer.wml   15) <li>We are looking for funding and sponsors. If you like Tor's goals, please

en/volunteer.wml   16)   <a href="<page donate>">take a moment to donate to support further
en/volunteer.wml   17)   Tor development</a>. Also, if you know any

en/volunteer.wml   18)   companies, NGOs, agencies, or other organizations that want communications

en/volunteer.wml   19)   security, let them know about us.</li>

volunteer.html     20) </ol>
volunteer.html     21) 

en/volunteer.wml   22) <a id="Usability"></a>

en/volunteer.wml   23) <h2><a class="anchor" href="#Usability">Supporting Applications</a></h2>

volunteer.html     24) <ol>

en/volunteer.wml   25) <li>We need more good ways to intercept DNS requests so they don't "leak" their

en/volunteer.wml   26) request to a local observer while we're trying to be anonymous. (This
en/volunteer.wml   27) happens because the application does the DNS resolve before going to
en/volunteer.wml   28) the SOCKS proxy.)</li>

en/volunteer.wml   29) <li>Tsocks/dsocks items:

en/volunteer.wml   30) <ul>
en/volunteer.wml   31) <li>We need to <a

en/volunteer.wml   32) href="https://wiki.torproject.org/noreply/TheOnionRouter/TSocksPatches">apply

en/volunteer.wml   33) all our tsocks patches</a> and maintain a new fork. We'll host it if
en/volunteer.wml   34) you want.</li>
en/volunteer.wml   35) <li>We should patch Dug Song's "dsocks" program to use Tor's
en/volunteer.wml   36) <i>mapaddress</i> commands from the controller interface, so we
en/volunteer.wml   37) don't waste a whole round-trip inside Tor doing the resolve before
en/volunteer.wml   38) connecting.</li>
en/volunteer.wml   39) <li>We need to make our <i>torify</i> script detect which of tsocks or
en/volunteer.wml   40) dsocks is installed, and call them appropriately. This probably means
en/volunteer.wml   41) unifying their interfaces, and might involve sharing code between them
en/volunteer.wml   42) or discarding one entirely.</li>
en/volunteer.wml   43) </ul>

en/volunteer.wml   44) </li>

en/volunteer.wml   45) <li>People running relays tell us they want to have one BandwidthRate

en/volunteer.wml   46) during some part of the day, and a different BandwidthRate at other
en/volunteer.wml   47) parts of the day. Rather than coding this inside Tor, we should have a
en/volunteer.wml   48) little script that speaks via the <a href="<page gui/index>">Tor
en/volunteer.wml   49) Controller Interface</a>, and does a setconf to change the bandwidth

en/volunteer.wml   50) rate. There is one for Unix and Mac already (it uses bash and cron),

en/volunteer.wml   51) but Windows users still need a solution.

en/volunteer.wml   52) </li>

en/volunteer.wml   53) <li>Tor can <a

en/volunteer.wml   54) href="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#ChooseEntryExit">exit

en/volunteer.wml   55) the Tor network from a particular exit node</a>, but we should be able
en/volunteer.wml   56) to specify just a country and have something automatically pick. The
en/volunteer.wml   57) best bet is to fetch Blossom's directory also, and run a local Blossom
en/volunteer.wml   58) client that fetches this directory securely (via Tor and checking its
en/volunteer.wml   59) signature), intercepts <tt>.country.blossom</tt> hostnames, and does
en/volunteer.wml   60) the right thing.</li>

volunteer.html     61) <li>Speaking of geolocation data, somebody should draw a map of the Earth

en/volunteer.wml   62) with a pin-point for each Tor relay. Bonus points if it updates as the

en/volunteer.wml   63) network grows and changes. Unfortunately, the easy ways to do this involve
en/volunteer.wml   64) sending all the data to Google and having them draw the map for you. How
en/volunteer.wml   65) much does this impact privacy, and do we have any other good options?</li>

volunteer.html     66) </ol>
volunteer.html     67) 

en/volunteer.wml   68) <a id="Documentation"></a>
en/volunteer.wml   69) <h2><a class="anchor" href="#Documentation">Documentation</a></h2>

volunteer.html     70) <ol>

en/volunteer.wml   71) <li>Please help Matt Edman with the documentation and how-tos for his

en/volunteer.wml   72) Tor controller,
en/volunteer.wml   73) <a href="http://vidalia-project.net/">Vidalia</a>.</li>

en/volunteer.wml   74) <li>Evaluate and document

en/volunteer.wml   75) <a href="https://wiki.torproject.org/wiki/TheOnionRouter/TorifyHOWTO">our

en/volunteer.wml   76) list of programs</a> that can be configured to use Tor.</li>

volunteer.html     77) <li>We need better documentation for dynamically intercepting

en/volunteer.wml   78) connections and sending them through Tor. tsocks (Linux), dsocks (BSD),

en/volunteer.wml   79) and freecap (Windows) seem to be good candidates, as would better
en/volunteer.wml   80) use of our new TransPort feature.</li>

en/volunteer.wml   81) <li>We have a huge list of <a href="https://wiki.torproject.org/noreply/TheOnionRouter/SupportPrograms">potentially useful

volunteer.html     82) programs that interface to Tor</a>. Which ones are useful in which
volunteer.html     83) situations? Please help us test them out and document your results.</li>

en/volunteer.wml   84) <li>Help translate the web page and documentation into other
en/volunteer.wml   85) languages. See the <a href="<page translation>">translation

en/volunteer.wml   86) guidelines</a> if you want to help out. We especially need Arabic or
en/volunteer.wml   87) Farsi translations, for the many Tor users in censored areas.</li>

volunteer.html     88) </ol>
volunteer.html     89) 

en/volunteer.wml   90) <a id="Coding"></a>

en/volunteer.wml   91) <a id="Summer"></a>
en/volunteer.wml   92) <a id="Projects"></a>

en/volunteer.wml   93) <h2><a class="anchor" href="#Projects">Good Coding Projects</a></h2>

en/volunteer.wml   94) 
en/volunteer.wml   95) <p>
en/volunteer.wml   96) You may find some of these projects to be good <a href="<page
en/volunteer.wml   97) gsoc>">Google Summer of Code 2008</a> ideas. We have labelled each idea

en/volunteer.wml   98) with how useful it would be to the overall Tor project

en/volunteer.wml   99) (priority), how much work we expect it would be (effort level), how much
en/volunteer.wml  100) clue you should start with (skill level), and which of our <a href="<page
en/volunteer.wml  101) people>#Core">core developers</a> would be good mentors.
en/volunteer.wml  102) </p>
en/volunteer.wml  103) 

en/volunteer.wml  104) <ol>
en/volunteer.wml  105) 

en/volunteer.wml  106) <li>

en/volunteer.wml  107) <b>Tor Exit Scanner improvements</b>

en/volunteer.wml  108) <br />

en/volunteer.wml  109) Priority: <i>High</i>
en/volunteer.wml  110) <br />
en/volunteer.wml  111) Effort Level: <i>High</i>
en/volunteer.wml  112) <br />

en/volunteer.wml  113) Skill Level: <i>High</i>
en/volunteer.wml  114) <br />

en/volunteer.wml  115) Likely Mentors: <i>Mike</i>

en/volunteer.wml  116) <br />

en/volunteer.wml  117) Applications as of 30 Mar 20:50 UTC: <i>3</i>
en/volunteer.wml  118) <br />

en/volunteer.wml  119) The Tor exit node scanner 'SoaT', part of the <a
en/volunteer.wml  120) href="<svnsandbox>torflow/">Torflow project</a>, makes connections out
en/volunteer.wml  121) of each Tor exit node and compares the content it gets back with what it
en/volunteer.wml  122) "should" get back. The goal is to notice misconfigured, broken, and even
en/volunteer.wml  123) malicious exit relays. Alas, the code is
en/volunteer.wml  124) currently written in rather rickety perl and relies on MD5sums of
en/volunteer.wml  125) entire documents in order to determine if exit nodes are modifying
en/volunteer.wml  126) content. The problem with this is threefold: 1) Perl sucks at life.
en/volunteer.wml  127) 2) The scanner can't verify pages that are dynamic, and attackers can
en/volunteer.wml  128) focus malicious content injection on only those dynamic pages. 3)
en/volunteer.wml  129) Pages change after a while (or based on GeoIP) and begin generating
en/volunteer.wml  130) false positives.

en/volunteer.wml  131) <br />

en/volunteer.wml  132) Ideally, soat.pl would be reimplemented in a sane language with a
en/volunteer.wml  133) robust html parser library (since the rest of Torflow is in Python
en/volunteer.wml  134) that would be nice, but it is not required), and calculate signatures only for
en/volunteer.wml  135) tags and content likely to be targeted by a malicious attacker (script
en/volunteer.wml  136) tags, object links, images, css). It should also be robust in the face of
en/volunteer.wml  137) changes to content outside of Tor, and ultimately even GeoIP localized
en/volunteer.wml  138) content.
en/volunteer.wml  139) <br />
en/volunteer.wml  140) This scanner would likely be run by the Directory Authorities and
en/volunteer.wml  141) report its results to the control port via the AuthDirBadExit config
en/volunteer.wml  142) setting.

en/volunteer.wml  143) <br />
en/volunteer.wml  144) </li>
en/volunteer.wml  145) 
en/volunteer.wml  146) <li>

en/volunteer.wml  147) <b>Tor Node Scanner improvements</b>

en/volunteer.wml  148) <br />

en/volunteer.wml  149) Priority: <i>High</i>

en/volunteer.wml  150) <br />

en/volunteer.wml  151) Effort Level: <i>Medium to High</i>

en/volunteer.wml  152) <br />
en/volunteer.wml  153) Skill Level: <i>Medium to High</i>
en/volunteer.wml  154) <br />

en/volunteer.wml  155) Likely Mentors: <i>Mike</i>

en/volunteer.wml  156) <br />

en/volunteer.wml  157) Applications as of 30 Mar 20:50 UTC: <i>1</i>
en/volunteer.wml  158) <br />

en/volunteer.wml  159) Similar to the exit scanner (or perhaps even during exit scanning),
en/volunteer.wml  160) statistics can be gathered about the reliability of nodes. Nodes that
en/volunteer.wml  161) fail too high a percentage of their circuits should not be given
en/volunteer.wml  162) Guard status. Perhaps they should have their reported bandwidth
en/volunteer.wml  163) penalized by some ratio as well, or just get marked as Invalid. In
en/volunteer.wml  164) addition, nodes that exhibit a very low average stream capacity but
en/volunteer.wml  165) advertise a very high node bandwidth can also be marked as Invalid.
en/volunteer.wml  166) Much of this statistics gathering is already done, it just needs to be
en/volunteer.wml  167) transformed into something that can be reported to the Directory
en/volunteer.wml  168) Authorities to blacklist/penalize nodes in such a way that clients
en/volunteer.wml  169) will listen.

en/volunteer.wml  170) <br />

en/volunteer.wml  171) In addition, these same statistics can be gathered about the traffic
en/volunteer.wml  172) through a node. Events can be added to the <a
en/volunteer.wml  173) href="https://www.torproject.org/svn/torctl/doc/howto.txt">Tor Control
en/volunteer.wml  174) Protocol</a> to
en/volunteer.wml  175) report if a circuit extend attempt through the node succeeds or fails, and
en/volunteer.wml  176) passive statistics can be gathered on both bandwidth and reliability
en/volunteer.wml  177) of other nodes via a node-based monitor using these events. Such a
en/volunteer.wml  178) scanner would also report information on oddly-behaving nodes to
en/volunteer.wml  179) the Directory Authorities, but a communication channel for this
en/volunteer.wml  180) currently does not exist and would need to be developed as well.
en/volunteer.wml  181) </li>
en/volunteer.wml  182) 
en/volunteer.wml  183) <li>
en/volunteer.wml  184) <b>Help track the overall Tor Network status</b>

en/volunteer.wml  185) <br />

en/volunteer.wml  186) Priority: <i>High</i>
en/volunteer.wml  187) <br />
en/volunteer.wml  188) Effort Level: <i>Medium</i>
en/volunteer.wml  189) <br />
en/volunteer.wml  190) Skill Level: <i>Medium</i>
en/volunteer.wml  191) <br />
en/volunteer.wml  192) Likely Mentors: <i>Roger, Nick, Mike</i>
en/volunteer.wml  193) <br />
en/volunteer.wml  194) It would be great to set up an automated system for tracking network
en/volunteer.wml  195) health over time, graphing it, etc. Part of this project would involve
en/volunteer.wml  196) inventing better metrics for assessing network health and growth. Is the
en/volunteer.wml  197) average uptime of the network increasing? How many relays are qualifying
en/volunteer.wml  198) for Guard status this month compared to last month? What's the turnover
en/volunteer.wml  199) in terms of new relays showing up and relays shutting off? Periodically
en/volunteer.wml  200) people collect brief snapshots, but where it gets really interesting is
en/volunteer.wml  201) when we start tracking data points over time.
en/volunteer.wml  202) <br />
en/volunteer.wml  203) Data could be collected from the "Tor Node Scanner" item above, from
en/volunteer.wml  204) the server descriptors that each relay publishes, and from other
en/volunteer.wml  205) sources. Results over time could be integrated into one of the <a
en/volunteer.wml  206) href="https://torstatus.blutmagie.de/">Tor Status</a> web pages, or be
en/volunteer.wml  207) kept separate. Speaking of the Tor Status pages, take a look at Roger's
en/volunteer.wml  208) <a href="http://archives.seul.org/or/talk/Jan-2008/msg00300.html">Tor
en/volunteer.wml  209) Status wish list</a>.
en/volunteer.wml  210) </li>
en/volunteer.wml  211) 
en/volunteer.wml  212) <li>
en/volunteer.wml  213) <b>Tor path selection improvements</b>
en/volunteer.wml  214) <br />
en/volunteer.wml  215) Priority: <i>High</i>
en/volunteer.wml  216) <br />
en/volunteer.wml  217) Effort Level: <i>Low to Medium</i>
en/volunteer.wml  218) <br />
en/volunteer.wml  219) Skill Level: <i>High</i>
en/volunteer.wml  220) <br />
en/volunteer.wml  221) Likely Mentors: <i>Roger, Nick, Mike</i>
en/volunteer.wml  222) <br />

en/volunteer.wml  223) Applications as of 30 Mar 20:50 UTC: <i>2</i>
en/volunteer.wml  224) <br />

en/volunteer.wml  225) Some simple improvements can be made to Tor's path selection to vastly
en/volunteer.wml  226) improve Tor speed. For instance, some of the (unofficial) <a
en/volunteer.wml  227) href="http://wiki.noreply.org/noreply/TheOnionRouter/FireFoxTorPerf">Tor
en/volunteer.wml  228) Performance Recommendations</a> on the wiki are to increase the number of
en/volunteer.wml  229) guards and decrease the CircuitBuildTimeout. Ideally, the client would
en/volunteer.wml  230) <a href="http://archives.seul.org/or/talk/Feb-2008/msg00012.html">learn
en/volunteer.wml  231) these values by gathering statistics on circuit construction
en/volunteer.wml  232) time</a> (and/or using values gained from Torflow), and set the timeouts
en/volunteer.wml  233) low enough such that some high percentile (75%, 90%, 1-stddev?) of
en/volunteer.wml  234) circuits succeed, yet extremely slow nodes are avoided. This would
en/volunteer.wml  235) involve some statistics gathering+basic research, and some changes to
en/volunteer.wml  236) Tor path selection code.
en/volunteer.wml  237) <br />
en/volunteer.wml  238) In addition, to improve path security, some elements from the <a
en/volunteer.wml  239) href="http://www.torproject.org/svn/trunk/doc/spec/proposals/115-two-hop-paths.txt">Two
en/volunteer.wml  240) Hop Paths proposal</a> could be done as part of this (since it will
en/volunteer.wml  241) likely touch the same code anyways), regardless of the adoption of
en/volunteer.wml  242) that proposal. In particular, clients probably should avoid guards that
en/volunteer.wml  243) seem to fail an excessive percentage of their circuits through them,
en/volunteer.wml  244) and non-firewalled clients should issue a warning if they are only able
en/volunteer.wml  245) to connect to a limited set of guard nodes. See also
en/volunteer.wml  246) <a href="http://archives.seul.org/or/dev/Feb-2008/msg00003.html">this
en/volunteer.wml  247) or-dev post</a>.

en/volunteer.wml  248) </li>
en/volunteer.wml  249) 
en/volunteer.wml  250) <li>

en/volunteer.wml  251) <b>Translation Wiki</b>
en/volunteer.wml  252) <br />
en/volunteer.wml  253) Priority: <i>High</i>
en/volunteer.wml  254) <br />
en/volunteer.wml  255) Effort Level: <i>Medium</i>
en/volunteer.wml  256) <br />
en/volunteer.wml  257) Skill Level: <i>Medium</i>
en/volunteer.wml  258) <br />
en/volunteer.wml  259) Likely Mentors: <i>Jacob</i>
en/volunteer.wml  260) <br />
en/volunteer.wml  261) We need a way to edit and translate sections of the website. Currently
en/volunteer.wml  262) the website is made up of a bunch of <a href="<svnwebsite>en/">wml
en/volunteer.wml  263) files</a>, and <a href="<page translation>">translators</a> fetch these
en/volunteer.wml  264) wml files, translate them in an editor, and either send us the translation
en/volunteer.wml  265) or use svn to commit them back. The current "cost" of publication of
en/volunteer.wml  266) website changes is quite high even for English language users. For a
en/volunteer.wml  267) single word change or any type of
en/volunteer.wml  268) minor change, the page may never be corrected or translated. It would
en/volunteer.wml  269) be nice to have a wiki that was specifically geared towards translation
en/volunteer.wml  270) and would somehow track the upstream (English) versions to indicate when
en/volunteer.wml  271) a fresh translation is needed, like our current
en/volunteer.wml  272) <a href="<page translation-status>">translation status page</a>. This
en/volunteer.wml  273) seems mostly like a job for a wiki
en/volunteer.wml  274) integrator or wiki software author. Certainly the person would need to
en/volunteer.wml  275) be interested in human languages and translation. They should at least
en/volunteer.wml  276) be minimally familiar with what Tor is; but they would not have to interact
en/volunteer.wml  277) with the software, only the documentation and the website.
en/volunteer.wml  278) </li>
en/volunteer.wml  279) 
en/volunteer.wml  280) <li>
en/volunteer.wml  281) <b>Better Debian/Ubuntu Packaging for Tor+Vidalia</b>

en/volunteer.wml  282) <br />

en/volunteer.wml  283) Priority: <i>High</i>
en/volunteer.wml  284) <br />
en/volunteer.wml  285) Effort Level: <i>Medium</i>
en/volunteer.wml  286) <br />
en/volunteer.wml  287) Skill Level: <i>Medium</i>
en/volunteer.wml  288) <br />

en/volunteer.wml  289) Likely Mentors: <i>Peter, Matt</i>

en/volunteer.wml  290) <br />

en/volunteer.wml  291) Applications as of 30 Mar 20:50 UTC: <i>1</i>
en/volunteer.wml  292) <br />

en/volunteer.wml  293) Vidalia currently doesn't play nicely on Debian and Ubuntu with the
en/volunteer.wml  294) default Tor packages. The current Tor packages automatically start Tor
en/volunteer.wml  295) as a daemon running as the debian-tor user and (sensibly) do not have a

en/volunteer.wml  296) <a href="<svnsandbox>doc/spec/control-spec.txt">ControlPort</a> defined
en/volunteer.wml  297) in the default torrc. Consequently, Vidalia will try

en/volunteer.wml  298) to start its own Tor process since it could not connect to the existing

en/volunteer.wml  299) Tor, and Vidalia's Tor process will then exit with an error message

en/volunteer.wml  300) the user likely doesn't understand since Tor cannot bind its listening

en/volunteer.wml  301) ports — they're already in use by the original Tor daemon.

en/volunteer.wml  302) <br />
en/volunteer.wml  303) The current solution involves either telling the user to stop the
en/volunteer.wml  304) existing Tor daemon and let Vidalia start its own Tor process, or
en/volunteer.wml  305) explaining to the user how to set a control port and password in their
en/volunteer.wml  306) torrc. A better solution on Debian would be to use Tor's ControlSocket,
en/volunteer.wml  307) which allows Vidalia to talk to Tor via a Unix domain socket, and could
en/volunteer.wml  308) possibly be enabled by default in Tor's Debian packages. Vidalia can

en/volunteer.wml  309) then authenticate to Tor using filesystem-based (cookie) authentication
en/volunteer.wml  310) if the user running Vidalia is also in the debian-tor group.

en/volunteer.wml  311) <br />
en/volunteer.wml  312) This project will first involve adding support for Tor's ControlSocket
en/volunteer.wml  313) to Vidalia. The student will then develop and test Debian and Ubuntu
en/volunteer.wml  314) packages for Vidalia that conform to Debian's packaging standards and

en/volunteer.wml  315) make sure they work well with the existing Tor packages. We can also

en/volunteer.wml  316) set up an apt repository to host the new Vidalia packages.
en/volunteer.wml  317) <br />

en/volunteer.wml  318) The next challenge would be to find an intuitive usable way for Vidalia
en/volunteer.wml  319) to be able to change Tor's configuration (torrc) even though it is
en/volunteer.wml  320) located in <code>/etc/tor/torrc</code> and thus immutable. The best
en/volunteer.wml  321) idea we've come up with so far is to feed Tor a new configuration via
en/volunteer.wml  322) the ControlSocket when Vidalia starts, but that's bad because Tor starts

en/volunteer.wml  323) each boot with a different configuration than the user wants. The second
en/volunteer.wml  324) best idea

en/volunteer.wml  325) we've come up with is for Vidalia to write out a temporary torrc file
en/volunteer.wml  326) and ask the user to manually move it to <code>/etc/tor/torrc</code>,
en/volunteer.wml  327) but that's bad because users shouldn't have to mess with files directly.
en/volunteer.wml  328) <br />

en/volunteer.wml  329) A student undertaking this project should have prior knowledge of
en/volunteer.wml  330) Debian package management and some C++ development experience. Previous
en/volunteer.wml  331) experience with Qt is helpful, but not required.
en/volunteer.wml  332) </li>
en/volunteer.wml  333) 

en/volunteer.wml  334) <li>
en/volunteer.wml  335) <b>Improving Tor's ability to resist censorship</b>
en/volunteer.wml  336) <br />
en/volunteer.wml  337) Priority: <i>High</i>
en/volunteer.wml  338) <br />
en/volunteer.wml  339) Effort Level: <i>High</i>
en/volunteer.wml  340) <br />
en/volunteer.wml  341) Skill Level: <i>High</i>
en/volunteer.wml  342) <br />
en/volunteer.wml  343) Likely Mentors: <i>Nick</i>
en/volunteer.wml  344) <br />
en/volunteer.wml  345) The Tor 0.2.0.x series makes <a
en/volunteer.wml  346) href="<svnsandbox>doc/design-paper/blocking.html">significant
en/volunteer.wml  347) improvements</a> in resisting national and organizational censorship.
en/volunteer.wml  348) But Tor still needs better mechanisms for some parts of its
en/volunteer.wml  349) anti-censorship design.  For example, current Tors can only listen on a
en/volunteer.wml  350) single address/port combination at a time.  There's
en/volunteer.wml  351) <a href="<svnsandbox>doc/spec/proposals/118-multiple-orports.txt">a
en/volunteer.wml  352) proposal to address this limitation</a> and allow clients to connect
en/volunteer.wml  353) to any given Tor on multiple addresses and ports, but it needs more
en/volunteer.wml  354) work.  Another anti-censorship project (far more difficult) is to try
en/volunteer.wml  355) to make Tor more scanning-resistant.  Right now, an adversary can identify
en/volunteer.wml  356) <a href="<svnsandbox>doc/spec/proposals/125-bridges.txt">Tor bridges</a>
en/volunteer.wml  357) just by trying to connect to them, following the Tor protocol, and
en/volunteer.wml  358) seeing if they respond.  To solve this, bridges could
en/volunteer.wml  359) <a href="<svnsandbox>doc/design-paper/blocking.html#tth_sEc9.3">act like
en/volunteer.wml  360) webservers</a> (HTTP or HTTPS) when contacted by port-scanning tools,
en/volunteer.wml  361) and not act like bridges until the user provides a bridge-specific key.
en/volunteer.wml  362) <br />
en/volunteer.wml  363) This project involves a lot of research and design. One of the big
en/volunteer.wml  364) challenges will be identifying and crafting approaches that can still
en/volunteer.wml  365) resist an adversary even after the adversary knows the design, and
en/volunteer.wml  366) then trading off censorship resistance with usability and robustness.
en/volunteer.wml  367) </li>
en/volunteer.wml  368) 
en/volunteer.wml  369) <li>
en/volunteer.wml  370) <b>Tor/Polipo/Vidalia Auto-Update Framework</b>
en/volunteer.wml  371) <br />
en/volunteer.wml  372) Priority: <i>Medium</i>
en/volunteer.wml  373) <br />
en/volunteer.wml  374) Effort Level: <i>High</i>
en/volunteer.wml  375) <br />
en/volunteer.wml  376) Skill Level: <i>High</i>
en/volunteer.wml  377) <br />
en/volunteer.wml  378) Likely Mentors: <i>Matt, Jacob</i>
en/volunteer.wml  379) <br />
en/volunteer.wml  380) We're in need of a good authenticated-update framework.
en/volunteer.wml  381) Vidalia already has the ability to notice when the user is running an
en/volunteer.wml  382) outdated or unrecommended version of Tor, using signed statements inside
en/volunteer.wml  383) the Tor directory information. Currently, Vidalia simply pops
en/volunteer.wml  384) up a little message box that lets the user know they should manually
en/volunteer.wml  385) upgrade. The goal of this project would be to extend Vidalia with the
en/volunteer.wml  386) ability to also fetch and install the updated Tor software for the
en/volunteer.wml  387) user. We should do the fetches via Tor when possible, but also fall back
en/volunteer.wml  388) to direct fetches in a smart way. Time permitting, we would also like
en/volunteer.wml  389) to be able to update other
en/volunteer.wml  390) applications included in the bundled installers, such as Polipo and
en/volunteer.wml  391) Vidalia itself.
en/volunteer.wml  392) <br />
en/volunteer.wml  393) To complete this project, the student will first need to first investigate
en/volunteer.wml  394) the existing auto-update frameworks (e.g., Sparkle on OS X) to evaluate
en/volunteer.wml  395) their strengths, weaknesses, security properties, and ability to be
en/volunteer.wml  396) integrated into Vidalia. If none are found to be suitable, the student
en/volunteer.wml  397) will design their own auto-update framework, document the design, and
en/volunteer.wml  398) then discuss the design with other developers to assess any security
en/volunteer.wml  399) issues. The student will then implement their framework (or integrate
en/volunteer.wml  400) an existing one) and test it.
en/volunteer.wml  401) <br />
en/volunteer.wml  402) A student undertaking this project should have good C++ development
en/volunteer.wml  403) experience. Previous experience with Qt is helpful, but not required. The
en/volunteer.wml  404) student should also have a good understanding of common security
en/volunteer.wml  405) practices, such as package signature verification. Good writing ability
en/volunteer.wml  406) is also important for this project, since a vital step of the project
en/volunteer.wml  407) will be producing a design document for others to review and discuss
en/volunteer.wml  408) with the student prior to implementation.
en/volunteer.wml  409) </li>
en/volunteer.wml  410) 
en/volunteer.wml  411) <li>
en/volunteer.wml  412) <b>An Improved and More Usable Network Map in Vidalia</b>
en/volunteer.wml  413) <br />
en/volunteer.wml  414) Priority: <i>Medium</i>
en/volunteer.wml  415) <br />
en/volunteer.wml  416) Effort Level: <i>Medium</i>
en/volunteer.wml  417) <br />
en/volunteer.wml  418) Skill Level: <i>Medium to High</i>
en/volunteer.wml  419) <br />
en/volunteer.wml  420) Likely Mentors: <i>Matt</i>
en/volunteer.wml  421) <br />
en/volunteer.wml  422) One of Vidalia's existing features is a network map that shows the user
en/volunteer.wml  423) the approximate geographic location of relays in the Tor network and
en/volunteer.wml  424) plots the paths the user's traffic takes as it is tunneled through the
en/volunteer.wml  425) Tor network. The map is currently not very interactive and has rather
en/volunteer.wml  426) poor graphics. Instead, we would like to leverage KDE's Marble widget
en/volunteer.wml  427) that gives us a better quality map and enables improved interactivity,
en/volunteer.wml  428) such as allowing the user to click on individual relays or circuits to
en/volunteer.wml  429) display additional information. We might also consider adding the ability
en/volunteer.wml  430) for users to click on a particular relay or a country containing one or
en/volunteer.wml  431) more Tor exit relays and say, "I want my connections to foo.com to exit
en/volunteer.wml  432) from here."
en/volunteer.wml  433) <br />
en/volunteer.wml  434) This project will first involve the student getting familiar with Vidalia
en/volunteer.wml  435) and the Marble widget's API. The student will then integrate the widget
en/volunteer.wml  436) into Vidalia and customize Marble to be better suited for our application,
en/volunteer.wml  437) such as making circuits clickable, storing cached map data in Vidalia's
en/volunteer.wml  438) own data directory, and customizing some of the widget's dialogs.
en/volunteer.wml  439) <br />
en/volunteer.wml  440) A student undertaking this project should have good C++ development
en/volunteer.wml  441) experience. Previous experience with Qt and CMake is helpful, but not
en/volunteer.wml  442) required.
en/volunteer.wml  443) </li>
en/volunteer.wml  444) 

en/volunteer.wml  445) <li>

en/volunteer.wml  446) <b>Tor Controller Status Event Interface</b>

en/volunteer.wml  447) <br />

en/volunteer.wml  448) Priority: <i>Medium</i>
en/volunteer.wml  449) <br />
en/volunteer.wml  450) Effort Level: <i>Medium</i>
en/volunteer.wml  451) <br />
en/volunteer.wml  452) Skill Level: <i>Medium</i>
en/volunteer.wml  453) <br />

en/volunteer.wml  454) Likely Mentors: <i>Matt, Roger</i>

en/volunteer.wml  455) <br />

en/volunteer.wml  456) There are a number of status changes inside Tor of which the user may need

en/volunteer.wml  457) to be informed. For example, if the user is trying to set up his Tor as a
en/volunteer.wml  458) relay and Tor decides that its ports are not reachable from outside

en/volunteer.wml  459) the user's network, we should alert the user. Currently, all the user

en/volunteer.wml  460) gets is a couple log messages in Vidalia's 'message log' window, which they

en/volunteer.wml  461) likely never see since they don't receive a notification that something
en/volunteer.wml  462) has gone wrong. Even if the user does actually look at the message log,
en/volunteer.wml  463) most of the messages make little sense to the novice user.
en/volunteer.wml  464) <br />
en/volunteer.wml  465) Tor has the ability to inform Vidalia of many such status changes, and
en/volunteer.wml  466) we recently implemented support for a couple of these events. Still,
en/volunteer.wml  467) there are many more status events the user should be informed of and we
en/volunteer.wml  468) need a better UI for actually displaying them to the user.
en/volunteer.wml  469) <br />
en/volunteer.wml  470) The goal of this project then is to design and implement a UI for
en/volunteer.wml  471) displaying Tor status events to the user. For example, we might put a
en/volunteer.wml  472) little badge on Vidalia's tray icon that alerts the user to new status
en/volunteer.wml  473) events they should look at. Double-clicking the icon could bring up a
en/volunteer.wml  474) dialog that summarizes recent status events in simple terms and maybe

en/volunteer.wml  475) suggests a remedy for any negative events if they can be corrected by

en/volunteer.wml  476) the user. Of course, this is just an example and the student is free to
en/volunteer.wml  477) suggest another approach.
en/volunteer.wml  478) <br />
en/volunteer.wml  479) A student undertaking this project should have good UI design and layout

en/volunteer.wml  480) and some C++ development experience. Previous experience with Qt and

en/volunteer.wml  481) Qt's Designer will be very helpful, but are not required. Some

en/volunteer.wml  482) English writing ability will also be useful, since this project will
en/volunteer.wml  483) likely involve writing small amounts of help documentation that should
en/volunteer.wml  484) be understandable by non-technical users. Bonus points for some graphic
en/volunteer.wml  485) design/Photoshop fu, since we might want/need some shiny new icons too.
en/volunteer.wml  486) </li>
en/volunteer.wml  487) 

en/volunteer.wml  488) <li>

en/volunteer.wml  489) <b>Improvements on our active browser configuration tester</b> -

en/volunteer.wml  490) <a href="https://check.torproject.org/">https://check.torproject.org/</a>

en/volunteer.wml  491) <br />

en/volunteer.wml  492) Priority: <i>Medium</i>
en/volunteer.wml  493) <br />
en/volunteer.wml  494) Effort Level: <i>Low</i>
en/volunteer.wml  495) <br />
en/volunteer.wml  496) Skill Level: <i>Low to Medium</i>
en/volunteer.wml  497) <br />

en/volunteer.wml  498) Likely Mentors: <i>Jacob, Steven</i>

en/volunteer.wml  499) <br />

en/volunteer.wml  500) We currently have a functional web page to detect if Tor is working. It

en/volunteer.wml  501) has a few places where it falls short. It requires improvements with

en/volunteer.wml  502) regard to default languages and functionality. It currently only responds
en/volunteer.wml  503) in English. In addition, it is a hack of a perl script that should have
en/volunteer.wml  504) never seen the light of day. It should probably be rewritten in python

en/volunteer.wml  505) with multi-lingual support in mind. It currently uses the <a
en/volunteer.wml  506) href="http://exitlist.torproject.org/">Tor DNS exit list</a>
en/volunteer.wml  507) and should continue to do so in the future. It currently result in certain

en/volunteer.wml  508) false positives and these should be discovered, documented, and fixed
en/volunteer.wml  509) where possible. Anyone working on this project should be interested in

en/volunteer.wml  510) DNS, basic perl or preferably python programming skills, and will have

en/volunteer.wml  511) to interact minimally with Tor to test their code.

en/volunteer.wml  512) <br />
en/volunteer.wml  513) If you want to make the project more exciting
en/volunteer.wml  514) and involve more design and coding, take a look at <a
en/volunteer.wml  515) href="<svnsandbox>doc/spec/proposals/131-verify-tor-usage.txt">proposal
en/volunteer.wml  516) 131-verify-tor-usage.txt</a>.

en/volunteer.wml  517) </li>
en/volunteer.wml  518) 
en/volunteer.wml  519) <li>

en/volunteer.wml  520) <b>Improvements on our DNS Exit List service</b> -

en/volunteer.wml  521) <a href="http://exitlist.torproject.org/">http://exitlist.torproject.org/</a>

en/volunteer.wml  522) <br />

en/volunteer.wml  523) Priority: <i>Medium</i>
en/volunteer.wml  524) <br />
en/volunteer.wml  525) Effort Level: <i>Low</i>
en/volunteer.wml  526) <br />
en/volunteer.wml  527) Skill Level: <i>Low</i>
en/volunteer.wml  528) <br />

en/volunteer.wml  529) Likely Mentors: <i>Jacob, Tup</i>

en/volunteer.wml  530) <br />

en/volunteer.wml  531) The <a href="http://p56soo2ibjkx23xo.onion/">exitlist software</a>
en/volunteer.wml  532) is written by our fabulous anonymous

en/volunteer.wml  533) contributer Tup. It's a DNS server written in Haskell that supports part of our <a

en/volunteer.wml  534) href="https://www.torproject.org/svn/trunk/doc/contrib/torel-design.txt">exitlist

en/volunteer.wml  535) design document</a>. Currently, it is functional and it is used by

en/volunteer.wml  536) check.torproject.org and other users. The issues that are outstanding
en/volunteer.wml  537) are mostly aesthetic. This wonderful service could use a much better
en/volunteer.wml  538) website using the common Tor theme. It would be best served with better
en/volunteer.wml  539) documentation for common services that use an RBL. It could use more
en/volunteer.wml  540) publicity. A person working on this project should be interested in DNS,
en/volunteer.wml  541) basic RBL configuration for popular services, and writing documentation.
en/volunteer.wml  542) The person would require minimal Tor interaction — testing their
en/volunteer.wml  543) own documentation at the very least. Furthermore, it would be useful

en/volunteer.wml  544) if they were interested in Haskell and wanted to implement more of the

en/volunteer.wml  545) torel-design.txt suggestions.
en/volunteer.wml  546) </li>
en/volunteer.wml  547) 
en/volunteer.wml  548) <li>

en/volunteer.wml  549) <b>Testing integration of Tor with web browsers for our end users</b>

en/volunteer.wml  550) <br />

en/volunteer.wml  551) Priority: <i>Medium</i>
en/volunteer.wml  552) <br />
en/volunteer.wml  553) Effort Level: <i>Medium</i>
en/volunteer.wml  554) <br />
en/volunteer.wml  555) Skill Level: <i>Medium</i>
en/volunteer.wml  556) <br />

en/volunteer.wml  557) Likely Mentors: <i>Jacob, Mike, Greg</i>

en/volunteer.wml  558) <br />

en/volunteer.wml  559) The Tor project currently lacks a solid test suite to ensure that a
en/volunteer.wml  560) user has a properly and safely configured web browser. It should test for as

en/volunteer.wml  561) many known issues as possible. It should attempt to decloak the

en/volunteer.wml  562) user in any way possible. Two current webpages that track these

en/volunteer.wml  563) kinds of issues are run by Greg Fleischer and HD Moore. Greg keeps a nice <a

en/volunteer.wml  564) href="http://pseudo-flaw.net/tor/torbutton/">list of issues along
en/volunteer.wml  565) with their proof of concept code, bug issues, etc</a>. HD Moore runs

en/volunteer.wml  566) the <a href="http://metasploit.com/research/projects/decloak/">metasploit

en/volunteer.wml  567) decloak website</a>. A student interested in defending Tor could start

en/volunteer.wml  568) by collecting as many workable and known methods for decloaking a

en/volunteer.wml  569) Tor user. (<a href="https://torcheck.xenobite.eu/">This page</a> may
en/volunteer.wml  570) be helpful as a start.) The student should be familiar with the common
en/volunteer.wml  571) pitfalls but

en/volunteer.wml  572) possibly have new methods in mind for implementing decloaking issues. The
en/volunteer.wml  573) website should ensure that it tells a user what their problem is. It
en/volunteer.wml  574) should help them to fix the problem or direct them to the proper support

en/volunteer.wml  575) channels. The student should be closely familiar with using Tor and how
en/volunteer.wml  576) to prevent Tor information leakage.

en/volunteer.wml  577) </li>
en/volunteer.wml  578) 

en/volunteer.wml  579) <li>

en/volunteer.wml  580) <b>Libevent and Tor integration improvements</b>
en/volunteer.wml  581) <br />

en/volunteer.wml  582) Priority: <i>Medium</i>
en/volunteer.wml  583) <br />
en/volunteer.wml  584) Effort Level: <i>High</i>
en/volunteer.wml  585) <br />
en/volunteer.wml  586) Skill Level: <i>Medium to High</i>
en/volunteer.wml  587) <br />

en/volunteer.wml  588) Likely Mentors: <i>Nick</i>

en/volunteer.wml  589) <br />

en/volunteer.wml  590) Tor should make better use of the more recent features of Niels
en/volunteer.wml  591) Provos's <a href="http://monkey.org/~provos/libevent/">Libevent</a>

en/volunteer.wml  592) library.  Tor already uses Libevent for its low-level asynchronous IO

en/volunteer.wml  593) calls, and could also use Libevent's increasingly good implementations

en/volunteer.wml  594) of network buffers and of HTTP.  This wouldn't be simply a matter of

en/volunteer.wml  595) replacing Tor's internal calls with calls to Libevent: instead, we'll

en/volunteer.wml  596) need to refactor Tor to use Libevent calls that do not follow the

en/volunteer.wml  597) same models as Tor's existing backends. Also, we'll need to add
en/volunteer.wml  598) missing functionality to Libevent as needed — most difficult likely
en/volunteer.wml  599) will be adding OpenSSL support on top of Libevent's buffer abstraction.
en/volunteer.wml  600) Also tricky will be adding rate-limiting to Libevent.

en/volunteer.wml  601) </li>
en/volunteer.wml  602) 
en/volunteer.wml  603) <li>

en/volunteer.wml  604) <b>Tuneup Tor!</b>
en/volunteer.wml  605) <br />

en/volunteer.wml  606) Priority: <i>Medium</i>
en/volunteer.wml  607) <br />
en/volunteer.wml  608) Effort Level: <i>Medium</i>
en/volunteer.wml  609) <br />
en/volunteer.wml  610) Skill Level: <i>Medium to High</i>
en/volunteer.wml  611) <br />

en/volunteer.wml  612) Likely Mentors: <i>Nick, Roger, Mike</i>

en/volunteer.wml  613) <br />

en/volunteer.wml  614) Right now, Tor relays measure and report their own bandwidth, and Tor
en/volunteer.wml  615) clients choose which relays to use in part based on that bandwidth.
en/volunteer.wml  616) This approach is vulnerable to
en/volunteer.wml  617) <a href="http://freehaven.net/anonbib/#bauer:wpes2007">attacks where
en/volunteer.wml  618) relays lie about their bandwidth</a>;
en/volunteer.wml  619) to address this, Tor currently caps the maximum bandwidth
en/volunteer.wml  620) it's willing to believe any relay provides.  This is a limited fix, and
en/volunteer.wml  621) a waste of bandwidth capacity to boot.  Instead,

en/volunteer.wml  622) Tor should possibly measure bandwidth in a more distributed way, perhaps
en/volunteer.wml  623) as described in the

en/volunteer.wml  624) <a href="http://freehaven.net/anonbib/author.html#snader08">"A Tune-up for
en/volunteer.wml  625) Tor"</a> paper

en/volunteer.wml  626) by Snader and Borisov. A student could use current testing code to

en/volunteer.wml  627) double-check this paper's findings and verify the extent to which they

en/volunteer.wml  628) dovetail with Tor as deployed in the wild, and determine good ways to
en/volunteer.wml  629) incorporate them into their suggestions Tor network without adding too

en/volunteer.wml  630) much communications overhead between relays and directory

en/volunteer.wml  631) authorities.

en/volunteer.wml  632) </li>
en/volunteer.wml  633) 

en/volunteer.wml  634) <!--

en/volunteer.wml  635) <li>

en/volunteer.wml  636) <b>Improving the Tor QA process: Continuous Integration for Windows builds</b>
en/volunteer.wml  637) <br />

en/volunteer.wml  638) Priority: <i>High</i>
en/volunteer.wml  639) <br />
en/volunteer.wml  640) Effort Level: <i>Medium</i>
en/volunteer.wml  641) <br />
en/volunteer.wml  642) Skill Level: <i>Medium</i>
en/volunteer.wml  643) <br />

en/volunteer.wml  644) Likely Mentors: <i>Jacob, Andrew</i>

en/volunteer.wml  645) <br />

en/volunteer.wml  646) It would be useful to have automated build processes for Windows and
en/volunteer.wml  647) probably other platforms. The purpose of having a continuous integration
en/volunteer.wml  648) build environment is to ensure that Windows isn't left behind for any of
en/volunteer.wml  649) the software projects used in the Tor project or its accompanying.<br />
en/volunteer.wml  650) Buildbot may be a good choice for this as it appears to support all of

en/volunteer.wml  651) the platforms Tor does. See the

en/volunteer.wml  652) <a href="http://en.wikipedia.org/wiki/BuildBot">wikipedia entry for

en/volunteer.wml  653) buildbot</a>.<br />
en/volunteer.wml  654) There may be better options and the person undertaking this task should
en/volunteer.wml  655) evaluate other options. Any person working on this automatic build
en/volunteer.wml  656) process should have experience or be willing to learn how to build all
en/volunteer.wml  657) of the respective Tor related code bases from scratch. Furthermore, the
en/volunteer.wml  658) person should have some experience building software in Windows
en/volunteer.wml  659) environments as this is the target audience we want to ensure we do not
en/volunteer.wml  660) leave behind. It would require close work with the Tor source code but

en/volunteer.wml  661) probably only in the form of building, not authoring.<br />
en/volunteer.wml  662) Additionally, we need to automate our performance testing for all platforms.

en/volunteer.wml  663) We've got buildbot (except on Windows — as noted above) to automate

en/volunteer.wml  664) our regular integration and compile testing already,
en/volunteer.wml  665) but we need to get our network simulation tests (as built in torflow)
en/volunteer.wml  666) updated for more recent versions of Tor, and designed to launch a test
en/volunteer.wml  667) network either on a single machine, or across several, so we can test

en/volunteer.wml  668) changes in performance on machines in different roles automatically.

en/volunteer.wml  669) </li>

en/volunteer.wml  670) -->

en/volunteer.wml  671) 

en/volunteer.wml  672) <li>

en/volunteer.wml  673) <b>Improve our unit testing process</b>
en/volunteer.wml  674) <br />

en/volunteer.wml  675) Priority: <i>Medium</i>
en/volunteer.wml  676) <br />
en/volunteer.wml  677) Effort Level: <i>Medium</i>
en/volunteer.wml  678) <br />
en/volunteer.wml  679) Skill Level: <i>Medium</i>
en/volunteer.wml  680) <br />

en/volunteer.wml  681) Likely Mentors: <i>Nick</i>

en/volunteer.wml  682) <br />

en/volunteer.wml  683) Tor needs to be far more tested. This is a multi-part effort. To start

en/volunteer.wml  684) with, our unit test coverage should rise substantially, especially in

en/volunteer.wml  685) the areas outside the utility functions. This will require significant

en/volunteer.wml  686) refactoring of some parts of Tor, in order to dissociate as much logic

en/volunteer.wml  687) as possible from globals.
en/volunteer.wml  688) <br />

en/volunteer.wml  689) Additionally, we need to automate our performance testing. We've got

en/volunteer.wml  690) buildbot to automate our regular integration and compile testing already
en/volunteer.wml  691) (though we need somebody to set it up on Windows),
en/volunteer.wml  692) but we need to get our network simulation tests (as built in TorFlow: see
en/volunteer.wml  693) the "Tor Node Scanner improvements" item)

en/volunteer.wml  694) updated for more recent versions of Tor, and designed to launch a test
en/volunteer.wml  695) network either on a single machine, or across several, so we can test

en/volunteer.wml  696) changes in performance on machines in different roles automatically.

en/volunteer.wml  697) </li>
en/volunteer.wml  698) 

en/volunteer.wml  699) <li>

en/volunteer.wml  700) <b>Help revive an independent Tor client implementation</b>

en/volunteer.wml  701) <br />

en/volunteer.wml  702) Priority: <i>Medium</i>

en/volunteer.wml  703) <br />
en/volunteer.wml  704) Effort Level: <i>High</i>
en/volunteer.wml  705) <br />
en/volunteer.wml  706) Skill Level: <i>Medium to High</i>
en/volunteer.wml  707) <br />

en/volunteer.wml  708) Likely Mentors: <i>Karsten, Nick</i>

en/volunteer.wml  709) <br />

en/volunteer.wml  710) Applications as of 30 Mar 20:50 UTC: <i>4</i>
en/volunteer.wml  711) <br />

en/volunteer.wml  712) Reanimate one of the approaches to implement a Tor client in Java,
en/volunteer.wml  713) e.g. the <a href="http://onioncoffee.sourceforge.net/">OnionCoffee
en/volunteer.wml  714) project</a>, and make it run on <a
en/volunteer.wml  715) href="http://code.google.com/android/">Android</a>. The first step
en/volunteer.wml  716) would be to port the existing code and execute it in an Android
en/volunteer.wml  717) environment. Next, the code should be updated to support the newer Tor
en/volunteer.wml  718) protocol versions like the <a href="<svnsandbox>doc/spec/dir-spec.txt">v3
en/volunteer.wml  719) directory protocol</a>. Further, support for requesting or even

en/volunteer.wml  720) providing Tor hidden services would be neat, but not required.
en/volunteer.wml  721) <br />
en/volunteer.wml  722) The student should be able to understand and write new Java code, including

en/volunteer.wml  723) a Java cryptography API. Being able to read C code would be helpful,

en/volunteer.wml  724) too. The student should be willing to read the existing documentation,

en/volunteer.wml  725) implement code based on it, and refine the documentation
en/volunteer.wml  726) when things are underdocumented. This project is mostly about coding and

en/volunteer.wml  727) to a small degree about design.
en/volunteer.wml  728) </li>
en/volunteer.wml  729) 
en/volunteer.wml  730) <li>

en/volunteer.wml  731) <b>Automatic system tests and automatically starting private Tor networks</b>

en/volunteer.wml  732) <br />

en/volunteer.wml  733) Priority: <i>Medium</i>
en/volunteer.wml  734) <br />
en/volunteer.wml  735) Effort Level: <i>Medium</i>
en/volunteer.wml  736) <br />
en/volunteer.wml  737) Skill Level: <i>Medium</i>
en/volunteer.wml  738) <br />

en/volunteer.wml  739) Likely Mentors: <i>Karsten, Nick, Roger</i>

en/volunteer.wml  740) <br />

en/volunteer.wml  741) Write a tool that runs automatic system tests in addition
en/volunteer.wml  742) to the existing unit tests. The Java-based Tor simulator <a
en/volunteer.wml  743) href="https://tor-svn.freehaven.net/svn/puppetor/trunk/">PuppeTor</a>
en/volunteer.wml  744) might be a good start for starting up a private Tor network, using it
en/volunteer.wml  745) for a while, and verifying that at least parts of it are working. This
en/volunteer.wml  746) project requires to conceive a blueprint for performing system tests
en/volunteer.wml  747) of private Tor networks, before starting to code. Typical types of
en/volunteer.wml  748) tests range from performing single requests over the private network to
en/volunteer.wml  749) manipulating exchanged messages and see if nodes handle corrupt messages

en/volunteer.wml  750) appropriately.
en/volunteer.wml  751) <br />
en/volunteer.wml  752) The student should be able to obtain a good understanding

en/volunteer.wml  753) of how Tor works and what problems and bugs could arise to design good

en/volunteer.wml  754) test cases. Understanding the existing Tor code structure and documentation is

en/volunteer.wml  755) vital. If PuppeTor is used, the student should also be able to understand
en/volunteer.wml  756) and possibly extend an existing Java application. This project is partly
en/volunteer.wml  757) about design and partly about coding.
en/volunteer.wml  758) </li>
en/volunteer.wml  759) 
en/volunteer.wml  760) <li>

en/volunteer.wml  761) <b>Bring moniTor to life</b>
en/volunteer.wml  762) <br />

en/volunteer.wml  763) Priority: <i>Medium</i>
en/volunteer.wml  764) <br />
en/volunteer.wml  765) Effort Level: <i>Medium</i>
en/volunteer.wml  766) <br />
en/volunteer.wml  767) Skill Level: <i>Low to Medium</i>
en/volunteer.wml  768) <br />

en/volunteer.wml  769) Likely Mentors: <i>Karsten, Jacob</i>

en/volunteer.wml  770) <br />

en/volunteer.wml  771) Applications as of 30 Mar 20:50 UTC: <i>2</i>
en/volunteer.wml  772) <br />

en/volunteer.wml  773) Implement a <a href="http://www.ss64.com/bash/top.html">top-like</a>
en/volunteer.wml  774) management tool for Tor relays. The purpose of such a tool would be
en/volunteer.wml  775) to monitor a local Tor relay via its control port and include useful
en/volunteer.wml  776) system information of the underlying machine. When running this tool, it
en/volunteer.wml  777) would dynamically update its content like top does for Linux processes.
en/volunteer.wml  778) <a href="http://archives.seul.org/or/dev/Jan-2008/msg00005.html">This

en/volunteer.wml  779) or-dev post</a> might be a good first read.
en/volunteer.wml  780) <br />
en/volunteer.wml  781) The student should be familiar

en/volunteer.wml  782) with or willing to learn about administering a Tor relay and configuring
en/volunteer.wml  783) it via its control port. As an initial prototype is written in Python,
en/volunteer.wml  784) some knowledge about writing Python code would be helpful, too. This

en/volunteer.wml  785) project is one part about identifying requirements to such a
en/volunteer.wml  786) tool and designing its interface, and one part lots of coding.

en/volunteer.wml  787) </li>
en/volunteer.wml  788) 

en/volunteer.wml  789) <li>
en/volunteer.wml  790) <b>Torbutton improvements</b>
en/volunteer.wml  791) <br />

en/volunteer.wml  792) Priority: <i>Medium</i>

en/volunteer.wml  793) <br />

en/volunteer.wml  794) Effort Level: <i>High</i>
en/volunteer.wml  795) <br />
en/volunteer.wml  796) Skill Level: <i>High</i>

en/volunteer.wml  797) <br />

en/volunteer.wml  798) Likely Mentors: <i>Mike</i>

en/volunteer.wml  799) <br/>
en/volunteer.wml  800) Torbutton has a number of improvements that can be made in the post-1.2
en/volunteer.wml  801) timeframe. Most of these are documented as feature requests in the <a

en/volunteer.wml  802) href="https://bugs.torproject.org/flyspray/index.php?tasks=all&project=5">Torbutton

en/volunteer.wml  803) flyspray section</a>. Good examples include: stripping off node.exit on http
en/volunteer.wml  804) headers, more fine-grained control over formfill blocking, improved referrer

en/volunteer.wml  805) spoofing based on the domain of the site (a-la <a

en/volunteer.wml  806) href="https://addons.mozilla.org/en-US/firefox/addon/953">refcontrol extension</a>),

en/volunteer.wml  807) tighter integration with Vidalia for reporting Tor status, a New Identity
en/volunteer.wml  808) button with Tor integration and multiple identity management, and anything

en/volunteer.wml  809) else you might think of.

en/volunteer.wml  810) <br />
en/volunteer.wml  811) This work would be independent coding in Javascript and the fun world of <a
en/volunteer.wml  812) href="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">XUL</a>,
en/volunteer.wml  813) with not too much involvement in the Tor internals.

en/volunteer.wml  814) </li>
en/volunteer.wml  815) 

en/volunteer.wml  816) <li>

en/volunteer.wml  817) <b>Porting Polipo to Windows</b>
en/volunteer.wml  818) <br />

en/volunteer.wml  819) Priority: <i>Medium</i>

en/volunteer.wml  820) <br />

en/volunteer.wml  821) Effort Level: <i>Medium</i>

en/volunteer.wml  822) <br />
en/volunteer.wml  823) Skill Level: <i>Medium to High</i>
en/volunteer.wml  824) <br />

en/volunteer.wml  825) Likely Mentors: <i>Andrew, Steven, Roger</i>

en/volunteer.wml  826) <br />

en/volunteer.wml  827) Help port <a
en/volunteer.wml  828) href="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</a> to

en/volunteer.wml  829) Windows. Example topics to tackle include:
en/volunteer.wml  830) 1) handle spaces in path names and understand the filesystem
en/volunteer.wml  831) namespace — that is, where application data, personal data,

en/volunteer.wml  832) and program data typically reside in various versions of Windows. 2) the
en/volunteer.wml  833) ability to handle ipv6 communications. 3) the ability to asynchronously
en/volunteer.wml  834) query name servers, find the system nameservers, and manage netbios
en/volunteer.wml  835) and dns queries. 4) use native regex capabilities of Windows, rather
en/volunteer.wml  836) than using 3rd party GNU regex libraries. 5) manage events and buffers
en/volunteer.wml  837) natively (i.e. in Unix-like OSes, Polipo defaults to 25% of ram, in
en/volunteer.wml  838) Windows it's whatever the config specifies). 6) some sort of GUI config
en/volunteer.wml  839) and reporting tool, bonus if it has a systray icon with right clickable
en/volunteer.wml  840) menu options. Double bonus if it's cross-platform compatible.
en/volunteer.wml  841) </li>
en/volunteer.wml  842) 
en/volunteer.wml  843) <li>

en/volunteer.wml  844) <b>Make our diagrams beautiful and automated</b>

en/volunteer.wml  845) <br />

en/volunteer.wml  846) Priority: <i>Medium</i>

en/volunteer.wml  847) <br />
en/volunteer.wml  848) Effort Level: <i>Low</i>
en/volunteer.wml  849) <br />
en/volunteer.wml  850) Skill Level: <i>Low</i>
en/volunteer.wml  851) <br />

en/volunteer.wml  852) Likely Mentors: <i>Andrew</i>

en/volunteer.wml  853) <br />

en/volunteer.wml  854) We need a way to generate the website diagrams (for example, the "How
en/volunteer.wml  855) Tor Works" pictures on the <a href="<page overview>">overview page</a>
en/volunteer.wml  856) from source, so we can translate them as UTF-8 text rather than edit
en/volunteer.wml  857) them by hand with Gimp. We might want to
en/volunteer.wml  858) integrate this as an wml file so translations are easy and images are
en/volunteer.wml  859) generated in multiple languages whenever we build the website. See the
en/volunteer.wml  860) "Translation Wiki" idea above.

en/volunteer.wml  861) </li>
en/volunteer.wml  862) 

en/volunteer.wml  863) <li>
en/volunteer.wml  864) <b>Improve the LiveCD offerings for the Tor community</b>
en/volunteer.wml  865) <br />

en/volunteer.wml  866) Priority: <i>Low</i>
en/volunteer.wml  867) <br />
en/volunteer.wml  868) Effort Level: <i>Low</i>
en/volunteer.wml  869) <br />
en/volunteer.wml  870) Skill Level: <i>Medium to High</i>
en/volunteer.wml  871) <br />

en/volunteer.wml  872) Likely Mentors: <i>Anonym, Jacob, Roger</i>

en/volunteer.wml  873) <br />

en/volunteer.wml  874) How can we make the <a

en/volunteer.wml  875) href="http://anonymityanywhere.com/incognito/">Incognito LiveCD</a>

en/volunteer.wml  876) easier to maintain, improve, and document?
en/volunteer.wml  877) </li>

en/volunteer.wml  878) 

en/volunteer.wml  879) <li>
en/volunteer.wml  880) <b>Rework and extend Blossom</b>
en/volunteer.wml  881) <br />
en/volunteer.wml  882) Priority: <i>Medium</i>
en/volunteer.wml  883) <br />
en/volunteer.wml  884) Effort Level: <i>Medium to High</i>
en/volunteer.wml  885) <br />
en/volunteer.wml  886) Skill Level: <i>Medium to High</i>
en/volunteer.wml  887) <br />
en/volunteer.wml  888) Likely Mentors: <i>Goodell</i>
en/volunteer.wml  889) <br />
en/volunteer.wml  890) Rework and extend Blossom (a tool for monitoring and
en/volunteer.wml  891) selecting appropriate Tor circuits based upon exit node requirements
en/volunteer.wml  892) specified by the user) to gather data in a self-contained way, with
en/volunteer.wml  893) parameters easily configurable by the user.  Blossom is presently
en/volunteer.wml  894) implemented as a single Python script that interfaces with Tor using the
en/volunteer.wml  895) Controller interface and depends upon metadata about Tor nodes obtained
en/volunteer.wml  896) via external processes, such as a webpage indicating status of the nodes
en/volunteer.wml  897) plus publically available data from DNS, whois, etc.  This project has
en/volunteer.wml  898) two parts: (1) Determine which additional metadata may be useful and
en/volunteer.wml  899) rework Blossom so that it cleanly obtains the metadata on its own rather
en/volunteer.wml  900) than depend upon external scripts (this may, for example, involve
en/volunteer.wml  901) additional threads or inter-process communication), and (2) develop a
en/volunteer.wml  902) means by which the user can easily configure Blossom, starting with a
en/volunteer.wml  903) configuration file and possibly working up to a web configuration engine.

en/volunteer.wml  904) Knowledge of Tor and Python are important; knowledge of
en/volunteer.wml  905) TCP, interprocess communication, and Perl will also be helpful.  An
en/volunteer.wml  906) interest in network neutrality is important as well, since the
en/volunteer.wml  907) principles of evaluating and understanding internet inconsistency are at
en/volunteer.wml  908) the core of the Blossom effort.

en/volunteer.wml  909) </li>
en/volunteer.wml  910) 
en/volunteer.wml  911) <li>
en/volunteer.wml  912) <b>Improve Blossom: Allow users to qualitatively describe exit nodes they desire</b>
en/volunteer.wml  913) <br />
en/volunteer.wml  914) Priority: <i>Low</i>
en/volunteer.wml  915) <br />
en/volunteer.wml  916) Effort Level: <i>Medium</i>
en/volunteer.wml  917) <br />
en/volunteer.wml  918) Skill Level: <i>Medium</i>
en/volunteer.wml  919) <br />
en/volunteer.wml  920) Likely Mentors: <i>Goodell</i>
en/volunteer.wml  921) <br />
en/volunteer.wml  922) Develop and implement a means of affording Blossom
en/volunteer.wml  923) users the ability to qualitatively describe the exit node that they
en/volunteer.wml  924) want.  The Internet is an inconsistent place: some Tor exit nodes see
en/volunteer.wml  925) the world differently than others.  As presently implemented, Blossom (a
en/volunteer.wml  926) tool for monitoring and selecting appropriate Tor circuits based upon
en/volunteer.wml  927) exit node requirements specified by the user) lacks a sufficiently rich
en/volunteer.wml  928) language to describe how the different vantage points are different.
en/volunteer.wml  929) For example, some exit nodes may have an upstream network that filters
en/volunteer.wml  930) certain kinds of traffic or certain websites.  Other exit nodes may
en/volunteer.wml  931) provide access to special content as a result of their location, perhaps
en/volunteer.wml  932) as a result of discrimination on the part of the content providers
en/volunteer.wml  933) themselves.  This project has two parts: (1) develop a language for
en/volunteer.wml  934) describing characteristics of networks in which exit nodes reside, and
en/volunteer.wml  935) (2) incorporate this language into Blossom so that users can select Tor
en/volunteer.wml  936) paths based upon the description.

en/volunteer.wml  937) Knowledge of Tor and Python are important; knowledge of
en/volunteer.wml  938) TCP, interprocess communication, and Perl will also be helpful.  An
en/volunteer.wml  939) interest in network neutrality is important as well, since the
en/volunteer.wml  940) principles of evaluating and understanding internet inconsistency are at
en/volunteer.wml  941) the core of the Blossom effort.

en/volunteer.wml  942) </li>
en/volunteer.wml  943) 

en/volunteer.wml  944) <li>
en/volunteer.wml  945) <b>Bring up new ideas!</b>
en/volunteer.wml  946) <br />
en/volunteer.wml  947) Don't like any of these? Look at the <a

en/volunteer.wml  948) href="<svnsandbox>doc/design-paper/roadmap-future.pdf">Tor development

en/volunteer.wml  949) roadmap</a> for more ideas.
en/volunteer.wml  950) </li>
en/volunteer.wml  951) 

en/volunteer.wml  952) </ol>
en/volunteer.wml  953) 

en/volunteer.wml  954) <h2><a class="anchor" href="#Coding">Coding and Design</a></h2>

volunteer.html    955) <ol>

en/volunteer.wml  956) <li>Tor relays don't work well on Windows XP. On

en/volunteer.wml  957) Windows, Tor uses the standard <tt>select()</tt> system

en/volunteer.wml  958) call, which uses space in the non-page pool. This means

en/volunteer.wml  959) that a medium sized Tor relay will empty the non-page pool, <a

en/volunteer.wml  960) href="https://wiki.torproject.org/noreply/TheOnionRouter/WindowsBufferProblems">causing

en/volunteer.wml  961) havoc and system crashes</a>. We should probably be using overlapped IO

en/volunteer.wml  962) instead. One solution would be to teach <a
en/volunteer.wml  963) href="http://www.monkey.org/~provos/libevent/">libevent</a> how to use
en/volunteer.wml  964) overlapped IO rather than select() on Windows, and then adapt Tor to

en/volunteer.wml  965) the new libevent interface. Christian King made a
en/volunteer.wml  966) <a href="https://tor-svn.freehaven.net/svn/libevent-urz/trunk/">good

en/volunteer.wml  967) start</a> on this in the summer of 2007.</li>

en/volunteer.wml  968) <li>We need to actually start building our <a href="<page
en/volunteer.wml  969) documentation>#DesignDoc">blocking-resistance design</a>. This involves

en/volunteer.wml  970) fleshing out the design, modifying many different pieces of Tor, adapting
en/volunteer.wml  971) <a href="http://vidalia-project.net/">Vidalia</a> so it supports the
en/volunteer.wml  972) new features, and planning for deployment.</li>

en/volunteer.wml  973) <li>We need a flexible simulator framework for studying end-to-end
en/volunteer.wml  974) traffic confirmation attacks. Many researchers have whipped up ad hoc
en/volunteer.wml  975) simulators to support their intuition either that the attacks work
en/volunteer.wml  976) really well or that some defense works great. Can we build a simulator
en/volunteer.wml  977) that's clearly documented and open enough that everybody knows it's
en/volunteer.wml  978) giving a reasonable answer? This will spur a lot of new research.
en/volunteer.wml  979) See the entry <a href="#Research">below</a> on confirmation attacks for
en/volunteer.wml  980) details on the research side of this task &mdash; who knows, when it's
en/volunteer.wml  981) done maybe you can help write a paper or three also.</li>

en/volunteer.wml  982) <li>Tor 0.1.1.x and later include support for hardware crypto accelerators

en/volunteer.wml  983) via OpenSSL. Nobody has ever tested it, though. Does somebody want to get

volunteer.html    984) a card and let us know how it goes?</li>

volunteer.html    985) <li>Perform a security analysis of Tor with <a
volunteer.html    986) href="http://en.wikipedia.org/wiki/Fuzz_testing">"fuzz"</a>. Determine

en/volunteer.wml  987) if there are good fuzzing libraries out there for what we want. Win fame by

volunteer.html    988) getting credit when we put out a new release because of you!</li>

volunteer.html    989) <li>Tor uses TCP for transport and TLS for link
volunteer.html    990) encryption. This is nice and simple, but it means all cells
volunteer.html    991) on a link are delayed when a single packet gets dropped, and
volunteer.html    992) it means we can only reasonably support TCP streams. We have a <a

en/volunteer.wml  993) href="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#TransportIPnotTCP">list

en/volunteer.wml  994) of reasons why we haven't shifted to UDP transport</a>, but it would
en/volunteer.wml  995) be great to see that list get shorter. We also have a proposed <a

en/volunteer.wml  996) href="<svnsandbox>doc/spec/proposals/100-tor-spec-udp.txt">specification
en/volunteer.wml  997) for Tor and

en/volunteer.wml  998) UDP</a> &mdash; please let us know what's wrong with it.</li>

volunteer.html    999) <li>We're not that far from having IPv6 support for destination addresses
volunteer.html   1000) (at exit nodes). If you care strongly about IPv6, that's probably the
volunteer.html   1001) first place to start.</li>

volunteer.html   1002) </ol>
volunteer.html   1003) 

en/volunteer.wml 1004) <a id="Research"></a>
en/volunteer.wml 1005) <h2><a class="anchor" href="#Research">Research</a></h2>

volunteer.html   1006) <ol>

volunteer.html   1007) <li>The "website fingerprinting attack": make a list of a few
volunteer.html   1008) hundred popular websites, download their pages, and make a set of
volunteer.html   1009) "signatures" for each site. Then observe a Tor client's traffic. As
volunteer.html   1010) you watch him receive data, you quickly approach a guess about which
volunteer.html   1011) (if any) of those sites he is visiting. First, how effective is
volunteer.html   1012) this attack on the deployed Tor codebase? Then start exploring
volunteer.html   1013) defenses: for example, we could change Tor's cell size from 512
volunteer.html   1014) bytes to 1024 bytes, we could employ padding techniques like <a
volunteer.html   1015) href="http://freehaven.net/anonbib/#timing-fc2004">defensive dropping</a>,
volunteer.html   1016) or we could add traffic delays. How much of an impact do these have,
volunteer.html   1017) and how much usability impact (using some suitable metric) is there from
volunteer.html   1018) a successful defense in each case?</li>

volunteer.html   1019) <li>The "end-to-end traffic confirmation attack":
volunteer.html   1020) by watching traffic at Alice and at Bob, we can <a
volunteer.html   1021) href="http://freehaven.net/anonbib/#danezis:pet2004">compare
volunteer.html   1022) traffic signatures and become convinced that we're watching the same
volunteer.html   1023) stream</a>. So far Tor accepts this as a fact of life and assumes this
volunteer.html   1024) attack is trivial in all cases. First of all, is that actually true? How
volunteer.html   1025) much traffic of what sort of distribution is needed before the adversary
volunteer.html   1026) is confident he has won? Are there scenarios (e.g. not transmitting much)
volunteer.html   1027) that slow down the attack? Do some traffic padding or traffic shaping
volunteer.html   1028) schemes work better than others?</li>

en/volunteer.wml 1029) <li>A related question is: Does running a relay/bridge provide additional
en/volunteer.wml 1030) protection against these timing attacks? Can an external adversary that can't

en/volunteer.wml 1031) see inside TLS links still recognize individual streams reliably?

en/volunteer.wml 1032) Does the amount of traffic carried degrade this ability any? What if the
en/volunteer.wml 1033) client-relay deliberately delayed upstream relayed traffic to create a queue
en/volunteer.wml 1034) that could be used to mimic timings of client downstream traffic to make it
en/volunteer.wml 1035) look like it was also relayed? This same queue could also be used for masking
en/volunteer.wml 1036) timings in client upstream traffic with the techniques from <a
en/volunteer.wml 1037) href="http://www.freehaven.net/anonbib/#ShWa-Timing06">adaptive padding</a>,
en/volunteer.wml 1038) but without the need for additional traffic. Would such an interleaving of
en/volunteer.wml 1039) client upstream traffic obscure timings for external adversaries? Would the
en/volunteer.wml 1040) strategies need to be adjusted for asymmetric links? For example, on
en/volunteer.wml 1041) asymmetric links, is it actually possible to differentiate client traffic from
en/volunteer.wml 1042) natural bursts due to their asymmetric capacity? Or is it easier than
en/volunteer.wml 1043) symmetric links for some other reason?</li>

volunteer.html   1044) <li>The "routing zones attack": most of the literature thinks of
volunteer.html   1045) the network path between Alice and her entry node (and between the
volunteer.html   1046) exit node and Bob) as a single link on some graph. In practice,
volunteer.html   1047) though, the path traverses many autonomous systems (ASes), and <a
volunteer.html   1048) href="http://freehaven.net/anonbib/#feamster:wpes2004">it's not uncommon
volunteer.html   1049) that the same AS appears on both the entry path and the exit path</a>.
volunteer.html   1050) Unfortunately, to accurately predict whether a given Alice, entry,
volunteer.html   1051) exit, Bob quad will be dangerous, we need to download an entire Internet
volunteer.html   1052) routing zone and perform expensive operations on it. Are there practical
volunteer.html   1053) approximations, such as avoiding IP addresses in the same /8 network?</li>

en/volunteer.wml 1054) <li>Other research questions regarding geographic diversity consider
en/volunteer.wml 1055) the tradeoff between choosing an efficient circuit and choosing a random

en/volunteer.wml 1056) circuit. Look at Stephen Rollyson's <a

en/volunteer.wml 1057) href="http://swiki.cc.gatech.edu:8080/ugResearch/uploads/7/ImprovingTor.pdf">position
en/volunteer.wml 1058) paper</a> on how to discard particularly slow choices without hurting

en/volunteer.wml 1059) anonymity "too much". This line of reasoning needs more work and more
en/volunteer.wml 1060) thinking, but it looks very promising.</li>

en/volunteer.wml 1061) <li>Tor doesn't work very well when relays have asymmetric bandwidth

volunteer.html   1062) (e.g. cable or DSL). Because Tor has separate TCP connections between
volunteer.html   1063) each hop, if the incoming bytes are arriving just fine and the outgoing
volunteer.html   1064) bytes are all getting dropped on the floor, the TCP push-back mechanisms
volunteer.html   1065) don't really transmit this information back to the incoming streams.
volunteer.html   1066) Perhaps Tor should detect when it's dropping a lot of outgoing packets,
volunteer.html   1067) and rate-limit incoming streams to regulate this itself? I can imagine
volunteer.html   1068) a build-up and drop-off scheme where we pick a conservative rate-limit,
volunteer.html   1069) slowly increase it until we get lost packets, back off, repeat. We
volunteer.html   1070) need somebody who's good with networks to simulate this and help design
volunteer.html   1071) solutions; and/or we need to understand the extent of the performance
volunteer.html   1072) degradation, and use this as motivation to reconsider UDP transport.</li>
volunteer.html   1073) <li>A related topic is congestion control. Is our
volunteer.html   1074) current design sufficient once we have heavy use? Maybe
volunteer.html   1075) we should experiment with variable-sized windows rather
volunteer.html   1076) than fixed-size windows? That seemed to go well in an <a
volunteer.html   1077) href="http://www.psc.edu/networking/projects/hpn-ssh/theory.php">ssh
volunteer.html   1078) throughput experiment</a>. We'll need to measure and tweak, and maybe
volunteer.html   1079) overhaul if the results are good.</li>

volunteer.html   1080) <li>To let dissidents in remote countries use Tor without being blocked
volunteer.html   1081) at their country's firewall, we need a way to get tens of thousands of
volunteer.html   1082) relays, not just a few hundred. We can imagine a Tor client GUI that

en/volunteer.wml 1083) has a "Tor for Freedom" button at the top that opens a port and relays a

volunteer.html   1084) few KB/s of traffic into the Tor network. (A few KB/s shouldn't be too
volunteer.html   1085) much hassle, and there are few abuse issues since they're not being exit
volunteer.html   1086) nodes.) But how do we distribute a list of these volunteer clients to the
volunteer.html   1087) good dissidents in an automated way that doesn't let the country-level

en/volunteer.wml 1088) firewalls intercept and enumerate them? This probably needs to work on a

en/volunteer.wml 1089) human-trust level. See our <a href="<page documentation>#DesignDoc">early
en/volunteer.wml 1090) blocking-resistance design document</a> and our
en/volunteer.wml 1091) <a

en/volunteer.wml 1092) href="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#BlockingResistance">FAQ

en/volunteer.wml 1093) entry</a> on this, and then read the <a
en/volunteer.wml 1094) href="http://freehaven.net/anonbib/topic.html#Communications_20Censorship">censorship
en/volunteer.wml 1095) resistance section of anonbib</a>.</li>

volunteer.html   1096) <li>Tor circuits are built one hop at a time, so in theory we have the
volunteer.html   1097) ability to make some streams exit from the second hop, some from the
volunteer.html   1098) third, and so on. This seems nice because it breaks up the set of exiting

en/volunteer.wml 1099) streams that a given relay can see. But if we want each stream to be safe,

volunteer.html   1100) the "shortest" path should be at least 3 hops long by our current logic, so
volunteer.html   1101) the rest will be even longer. We need to examine this performance / security
volunteer.html   1102) tradeoff.</li>

en/volunteer.wml 1103) <li>It's not that hard to DoS Tor relays or directory authorities. Are client

volunteer.html   1104) puzzles the right answer? What other practical approaches are there? Bonus
volunteer.html   1105) if they're backward-compatible with the current Tor protocol.</li>

en/volunteer.wml 1106) <li>Programs like <a
en/volunteer.wml 1107) href="https://torbutton.torproject.org/dev/">Torbutton</a> aim to hide
en/volunteer.wml 1108) your browser's UserAgent string by replacing it with a uniform answer for
en/volunteer.wml 1109) every Tor user. That way the attacker can't splinter Tor's anonymity set
en/volunteer.wml 1110) by looking at that header. It tries to pick a string that is commonly used
en/volunteer.wml 1111) by non-Tor users too, so it doesn't stand out. Question one: how badly
en/volunteer.wml 1112) do we hurt ourselves by periodically updating the version of Firefox
en/volunteer.wml 1113) that Torbutton claims to be? If we update it too often, we splinter the
en/volunteer.wml 1114) anonymity sets ourselves. If we don't update it often enough, then all the
en/volunteer.wml 1115) Tor users stand out because they claim to be running a quite old version
en/volunteer.wml 1116) of Firefox. The answer here probably depends on the Firefox versions seen
en/volunteer.wml 1117) in the wild. Question two: periodically people ask us to cycle through N
en/volunteer.wml 1118) UserAgent strings rather than stick with one. Does this approach help,
en/volunteer.wml 1119) hurt, or not matter? Consider: cookies and recognizing Torbutton users
en/volunteer.wml 1120) by their rotating UserAgents; malicious websites who only attack certain
en/volunteer.wml 1121) browsers; and whether the answers to question one impact this answer.
en/volunteer.wml 1122) </li>

volunteer.html   1123) </ol>
volunteer.html   1124) 

en/volunteer.wml 1125) <p>

en/volunteer.wml 1126) <a href="<page contact>">Let us know</a> if you've made progress on any
en/volunteer.wml 1127) of these!

en/volunteer.wml 1128) </p>

volunteer.html   1129) 

en/volunteer.wml 1130)   </div><!-- #main -->

volunteer.html   1131) 

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