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/Polipo/Vidalia Auto-Update Framework</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>Matt, Jacob</i>

en/volunteer.wml  116) <br />

en/volunteer.wml  117) We're in need of a good authenticated-update framework.

en/volunteer.wml  118) Vidalia already has the ability to notice when the user is running an

en/volunteer.wml  119) outdated or unrecommended version of Tor, using signed statements inside
en/volunteer.wml  120) the Tor directory information. Currently, Vidalia simply pops

en/volunteer.wml  121) up a little message box that lets the user know they should manually
en/volunteer.wml  122) upgrade. The goal of this project would be to extend Vidalia with the
en/volunteer.wml  123) ability to also fetch and install the updated Tor software for the

en/volunteer.wml  124) user. We should do the fetches via Tor when possible, but also fall back
en/volunteer.wml  125) to direct fetches in a smart way. Time permitting, we would also like
en/volunteer.wml  126) to be able to update other

en/volunteer.wml  127) applications included in the bundled installers, such as Polipo and
en/volunteer.wml  128) Vidalia itself.
en/volunteer.wml  129) <br />
en/volunteer.wml  130) To complete this project, the student will first need to first investigate
en/volunteer.wml  131) the existing auto-update frameworks (e.g., Sparkle on OS X) to evaluate
en/volunteer.wml  132) their strengths, weaknesses, security properties, and ability to be
en/volunteer.wml  133) integrated into Vidalia. If none are found to be suitable, the student
en/volunteer.wml  134) will design their own auto-update framework, document the design, and
en/volunteer.wml  135) then discuss the design with other developers to assess any security
en/volunteer.wml  136) issues. The student will then implement their framework (or integrate
en/volunteer.wml  137) an existing one) and test it.
en/volunteer.wml  138) <br />
en/volunteer.wml  139) A student undertaking this project should have good C++ development
en/volunteer.wml  140) experience. Previous experience with Qt is helpful, but not required. The

en/volunteer.wml  141) student should also have a good understanding of common security

en/volunteer.wml  142) practices, such as package signature verification. Good writing ability
en/volunteer.wml  143) is also important for this project, since a vital step of the project
en/volunteer.wml  144) will be producing a design document for others to review and discuss
en/volunteer.wml  145) with the student prior to implementation.
en/volunteer.wml  146) </li>
en/volunteer.wml  147) 
en/volunteer.wml  148) <li>

en/volunteer.wml  149) <b>An Improved and More Usable Network Map in Vidalia</b>

en/volunteer.wml  150) <br />

en/volunteer.wml  151) Priority: <i>Medium</i>
en/volunteer.wml  152) <br />
en/volunteer.wml  153) Effort Level: <i>Medium</i>
en/volunteer.wml  154) <br />
en/volunteer.wml  155) Skill Level: <i>Medium to High</i>
en/volunteer.wml  156) <br />

en/volunteer.wml  157) Likely Mentors: <i>Matt</i>

en/volunteer.wml  158) <br />

en/volunteer.wml  159) One of Vidalia's existing features is a network map that shows the user
en/volunteer.wml  160) the approximate geographic location of relays in the Tor network and
en/volunteer.wml  161) plots the paths the user's traffic takes as it is tunneled through the
en/volunteer.wml  162) Tor network. The map is currently not very interactive and has rather
en/volunteer.wml  163) poor graphics. Instead, we would like to leverage KDE's Marble widget
en/volunteer.wml  164) that gives us a better quality map and enables improved interactivity,
en/volunteer.wml  165) such as allowing the user to click on individual relays or circuits to
en/volunteer.wml  166) display additional information. We might also consider adding the ability
en/volunteer.wml  167) for users to click on a particular relay or a country containing one or

en/volunteer.wml  168) more Tor exit relays and say, "I want my connections to foo.com to exit
en/volunteer.wml  169) from here."

en/volunteer.wml  170) <br />
en/volunteer.wml  171) This project will first involve the student getting familiar with Vidalia
en/volunteer.wml  172) and the Marble widget's API. The student will then integrate the widget
en/volunteer.wml  173) into Vidalia and customize Marble to be better suited for our application,
en/volunteer.wml  174) such as making circuits clickable, storing cached map data in Vidalia's
en/volunteer.wml  175) own data directory, and customizing some of the widget's dialogs.
en/volunteer.wml  176) <br />
en/volunteer.wml  177) A student undertaking this project should have good C++ development
en/volunteer.wml  178) experience. Previous experience with Qt and CMake is helpful, but not
en/volunteer.wml  179) required.
en/volunteer.wml  180) </li>
en/volunteer.wml  181) 
en/volunteer.wml  182) <li>

en/volunteer.wml  183) <b>Better Debian Packaging for Tor+Vidalia</b>

en/volunteer.wml  184) <br />

en/volunteer.wml  185) Priority: <i>High</i>
en/volunteer.wml  186) <br />
en/volunteer.wml  187) Effort Level: <i>Medium</i>
en/volunteer.wml  188) <br />
en/volunteer.wml  189) Skill Level: <i>Medium</i>
en/volunteer.wml  190) <br />

en/volunteer.wml  191) Likely Mentors: <i>Peter, Matt</i>

en/volunteer.wml  192) <br />

en/volunteer.wml  193) Vidalia currently doesn't play nicely on Debian and Ubuntu with the
en/volunteer.wml  194) default Tor packages. The current Tor packages automatically start Tor
en/volunteer.wml  195) as a daemon running as the debian-tor user and (sensibly) do not have a

en/volunteer.wml  196) <a href="<svnsandbox>doc/spec/control-spec.txt">ControlPort</a> defined
en/volunteer.wml  197) in the default torrc. Consequently, Vidalia will try

en/volunteer.wml  198) to start its own Tor process since it could not connect to the existing

en/volunteer.wml  199) Tor, and Vidalia's Tor process will then exit with an error message

en/volunteer.wml  200) the user likely doesn't understand since Tor cannot bind its listening

en/volunteer.wml  201) ports — they're already in use by the original Tor daemon.

en/volunteer.wml  202) <br />
en/volunteer.wml  203) The current solution involves either telling the user to stop the
en/volunteer.wml  204) existing Tor daemon and let Vidalia start its own Tor process, or
en/volunteer.wml  205) explaining to the user how to set a control port and password in their
en/volunteer.wml  206) torrc. A better solution on Debian would be to use Tor's ControlSocket,
en/volunteer.wml  207) which allows Vidalia to talk to Tor via a Unix domain socket, and could
en/volunteer.wml  208) possibly be enabled by default in Tor's Debian packages. Vidalia can

en/volunteer.wml  209) then authenticate to Tor using filesystem-based (cookie) authentication
en/volunteer.wml  210) if the user running Vidalia is also in the debian-tor group.

en/volunteer.wml  211) <br />
en/volunteer.wml  212) This project will first involve adding support for Tor's ControlSocket
en/volunteer.wml  213) to Vidalia. The student will then develop and test Debian and Ubuntu
en/volunteer.wml  214) packages for Vidalia that conform to Debian's packaging standards and

en/volunteer.wml  215) make sure they work well with the existing Tor packages. We can also

en/volunteer.wml  216) set up an apt repository to host the new Vidalia packages.
en/volunteer.wml  217) <br />

en/volunteer.wml  218) The next challenge would be to find an intuitive usable way for Vidalia
en/volunteer.wml  219) to be able to change Tor's configuration (torrc) even though it is
en/volunteer.wml  220) located in <code>/etc/tor/torrc</code> and thus immutable. The best
en/volunteer.wml  221) idea we've come up with so far is to feed Tor a new configuration via
en/volunteer.wml  222) the ControlSocket when Vidalia starts, but that's bad because Tor starts

en/volunteer.wml  223) each boot with a different configuration than the user wants. The second
en/volunteer.wml  224) best idea

en/volunteer.wml  225) we've come up with is for Vidalia to write out a temporary torrc file
en/volunteer.wml  226) and ask the user to manually move it to <code>/etc/tor/torrc</code>,
en/volunteer.wml  227) but that's bad because users shouldn't have to mess with files directly.
en/volunteer.wml  228) <br />

en/volunteer.wml  229) A student undertaking this project should have prior knowledge of
en/volunteer.wml  230) Debian package management and some C++ development experience. Previous
en/volunteer.wml  231) experience with Qt is helpful, but not required.
en/volunteer.wml  232) </li>
en/volunteer.wml  233) 
en/volunteer.wml  234) <li>

en/volunteer.wml  235) <b>Tor Controller Status Event Interface</b>

en/volunteer.wml  236) <br />

en/volunteer.wml  237) Priority: <i>Medium</i>
en/volunteer.wml  238) <br />
en/volunteer.wml  239) Effort Level: <i>Medium</i>
en/volunteer.wml  240) <br />
en/volunteer.wml  241) Skill Level: <i>Medium</i>
en/volunteer.wml  242) <br />

en/volunteer.wml  243) Likely Mentors: <i>Matt, Roger</i>

en/volunteer.wml  244) <br />

en/volunteer.wml  245) There are a number of status changes inside Tor of which the user may need

en/volunteer.wml  246) to be informed. For example, if the user is trying to set up his Tor as a
en/volunteer.wml  247) relay and Tor decides that its ports are not reachable from outside

en/volunteer.wml  248) the user's network, we should alert the user. Currently, all the user

en/volunteer.wml  249) gets is a couple log messages in Vidalia's 'message log' window, which they

en/volunteer.wml  250) likely never see since they don't receive a notification that something
en/volunteer.wml  251) has gone wrong. Even if the user does actually look at the message log,
en/volunteer.wml  252) most of the messages make little sense to the novice user.
en/volunteer.wml  253) <br />
en/volunteer.wml  254) Tor has the ability to inform Vidalia of many such status changes, and
en/volunteer.wml  255) we recently implemented support for a couple of these events. Still,
en/volunteer.wml  256) there are many more status events the user should be informed of and we
en/volunteer.wml  257) need a better UI for actually displaying them to the user.
en/volunteer.wml  258) <br />
en/volunteer.wml  259) The goal of this project then is to design and implement a UI for
en/volunteer.wml  260) displaying Tor status events to the user. For example, we might put a
en/volunteer.wml  261) little badge on Vidalia's tray icon that alerts the user to new status
en/volunteer.wml  262) events they should look at. Double-clicking the icon could bring up a
en/volunteer.wml  263) dialog that summarizes recent status events in simple terms and maybe

en/volunteer.wml  264) suggests a remedy for any negative events if they can be corrected by

en/volunteer.wml  265) the user. Of course, this is just an example and the student is free to
en/volunteer.wml  266) suggest another approach.
en/volunteer.wml  267) <br />
en/volunteer.wml  268) A student undertaking this project should have good UI design and layout

en/volunteer.wml  269) and some C++ development experience. Previous experience with Qt and 
en/volunteer.wml  270) Qt's Designer will be very helpful, but are not required. Some

en/volunteer.wml  271) English writing ability will also be useful, since this project will
en/volunteer.wml  272) likely involve writing small amounts of help documentation that should
en/volunteer.wml  273) be understandable by non-technical users. Bonus points for some graphic
en/volunteer.wml  274) design/Photoshop fu, since we might want/need some shiny new icons too.
en/volunteer.wml  275) </li>
en/volunteer.wml  276) 

en/volunteer.wml  277) <li>

en/volunteer.wml  278) <b>Translation Wiki</b>

en/volunteer.wml  279) <br />

en/volunteer.wml  280) Priority: <i>High</i>
en/volunteer.wml  281) <br />
en/volunteer.wml  282) Effort Level: <i>Medium</i>
en/volunteer.wml  283) <br />
en/volunteer.wml  284) Skill Level: <i>Medium</i>
en/volunteer.wml  285) <br />

en/volunteer.wml  286) Likely Mentors: <i>Jacob</i>

en/volunteer.wml  287) <br />

en/volunteer.wml  288) We need a way to edit and translate sections of the website. Currently

en/volunteer.wml  289) the website is made up of a bunch of <a href="<svnwebsite>en/">wml

en/volunteer.wml  290) files</a>, and <a href="<page translation>">translators</a> fetch these
en/volunteer.wml  291) wml files, translate them in an editor, and either send us the translation
en/volunteer.wml  292) or use svn to commit them back. The current "cost" of publication of
en/volunteer.wml  293) website changes is quite high even for English language users. For a
en/volunteer.wml  294) single word change or any type of

en/volunteer.wml  295) minor change, the page may never be corrected or translated. It would

en/volunteer.wml  296) be nice to have a wiki that was specifically geared towards translation
en/volunteer.wml  297) and would somehow track the upstream (English) versions to indicate when

en/volunteer.wml  298) a fresh translation is needed, like our current
en/volunteer.wml  299) <a href="<page translation-status>">translation status page</a>. This
en/volunteer.wml  300) seems mostly like a job for a wiki

en/volunteer.wml  301) integrator or wiki software author. Certainly the person would need to
en/volunteer.wml  302) be interested in human languages and translation. They should at least

en/volunteer.wml  303) be minimally familiar with what Tor is; but they would not have to interact
en/volunteer.wml  304) with the software, only the documentation and the website.

en/volunteer.wml  305) </li>
en/volunteer.wml  306) 
en/volunteer.wml  307) <li>

en/volunteer.wml  308) <b>Improvements on our active browser configuration tester</b> - 

en/volunteer.wml  309) <a href="https://check.torproject.org/">https://check.torproject.org/</a>

en/volunteer.wml  310) <br />

en/volunteer.wml  311) Priority: <i>Medium</i>
en/volunteer.wml  312) <br />
en/volunteer.wml  313) Effort Level: <i>Low</i>
en/volunteer.wml  314) <br />
en/volunteer.wml  315) Skill Level: <i>Low to Medium</i>
en/volunteer.wml  316) <br />

en/volunteer.wml  317) Likely Mentors: <i>Jacob, Steven</i>

en/volunteer.wml  318) <br />

en/volunteer.wml  319) We currently have a functional web page to detect if Tor is working. It

en/volunteer.wml  320) has a few places where it falls short. It requires improvements with

en/volunteer.wml  321) regard to default languages and functionality. It currently only responds
en/volunteer.wml  322) in English. In addition, it is a hack of a perl script that should have
en/volunteer.wml  323) never seen the light of day. It should probably be rewritten in python

en/volunteer.wml  324) with multi-lingual support in mind. It currently uses the <a
en/volunteer.wml  325) href="http://exitlist.torproject.org/">Tor DNS exit list</a>
en/volunteer.wml  326) and should continue to do so in the future. It currently result in certain

en/volunteer.wml  327) false positives and these should be discovered, documented, and fixed
en/volunteer.wml  328) where possible. Anyone working on this project should be interested in

en/volunteer.wml  329) DNS, basic perl or preferably python programming skills, and will have

en/volunteer.wml  330) to interact minimally with Tor to test their code.

en/volunteer.wml  331) <br />
en/volunteer.wml  332) If you want to make the project more exciting
en/volunteer.wml  333) and involve more design and coding, take a look at <a
en/volunteer.wml  334) href="<svnsandbox>doc/spec/proposals/131-verify-tor-usage.txt">proposal
en/volunteer.wml  335) 131-verify-tor-usage.txt</a>.

en/volunteer.wml  336) </li>
en/volunteer.wml  337) 
en/volunteer.wml  338) <li>

en/volunteer.wml  339) <b>Improvements on our DNS Exit List service</b> - 

en/volunteer.wml  340) <a href="http://exitlist.torproject.org/">http://exitlist.torproject.org/</a>

en/volunteer.wml  341) <br />

en/volunteer.wml  342) Priority: <i>Medium</i>
en/volunteer.wml  343) <br />
en/volunteer.wml  344) Effort Level: <i>Low</i>
en/volunteer.wml  345) <br />
en/volunteer.wml  346) Skill Level: <i>Low</i>
en/volunteer.wml  347) <br />

en/volunteer.wml  348) Likely Mentors: <i>Jacob, Tup</i>

en/volunteer.wml  349) <br />

en/volunteer.wml  350) The <a href="http://p56soo2ibjkx23xo.onion/">exitlist software</a>
en/volunteer.wml  351) is written by our fabulous anonymous

en/volunteer.wml  352) contributer Tup. It's a DNS server written in Haskell that supports part of our <a

en/volunteer.wml  353) href="https://www.torproject.org/svn/trunk/doc/contrib/torel-design.txt">exitlist

en/volunteer.wml  354) design document</a>. Currently, it is functional and it is used by

en/volunteer.wml  355) check.torproject.org and other users. The issues that are outstanding
en/volunteer.wml  356) are mostly aesthetic. This wonderful service could use a much better
en/volunteer.wml  357) website using the common Tor theme. It would be best served with better
en/volunteer.wml  358) documentation for common services that use an RBL. It could use more
en/volunteer.wml  359) publicity. A person working on this project should be interested in DNS,
en/volunteer.wml  360) basic RBL configuration for popular services, and writing documentation.
en/volunteer.wml  361) The person would require minimal Tor interaction — testing their
en/volunteer.wml  362) own documentation at the very least. Furthermore, it would be useful

en/volunteer.wml  363) if they were interested in Haskell and wanted to implement more of the

en/volunteer.wml  364) torel-design.txt suggestions.
en/volunteer.wml  365) </li>
en/volunteer.wml  366) 
en/volunteer.wml  367) <li>

en/volunteer.wml  368) <b>Testing integration of Tor with web browsers for our end users</b>

en/volunteer.wml  369) <br />

en/volunteer.wml  370) Priority: <i>Medium</i>
en/volunteer.wml  371) <br />
en/volunteer.wml  372) Effort Level: <i>Medium</i>
en/volunteer.wml  373) <br />
en/volunteer.wml  374) Skill Level: <i>Medium</i>
en/volunteer.wml  375) <br />

en/volunteer.wml  376) Likely Mentors: <i>Jacob, Mike, Greg</i>

en/volunteer.wml  377) <br />

en/volunteer.wml  378) The Tor project currently lacks a solid test suite to ensure that a
en/volunteer.wml  379) user has a properly and safely configured web browser. It should test for as

en/volunteer.wml  380) many known issues as possible. It should attempt to decloak the

en/volunteer.wml  381) user in any way possible. Two current webpages that track these

en/volunteer.wml  382) kinds of issues are run by Greg Fleischer and HD Moore. Greg keeps a nice <a

en/volunteer.wml  383) href="http://pseudo-flaw.net/tor/torbutton/">list of issues along
en/volunteer.wml  384) with their proof of concept code, bug issues, etc</a>. HD Moore runs

en/volunteer.wml  385) the <a href="http://metasploit.com/research/projects/decloak/">metasploit

en/volunteer.wml  386) decloak website</a>. A student interested in defending Tor could start

en/volunteer.wml  387) by collecting as many workable and known methods for decloaking a

en/volunteer.wml  388) Tor user. (<a href="https://torcheck.xenobite.eu/">This page</a> may
en/volunteer.wml  389) be helpful as a start.) The student should be familiar with the common
en/volunteer.wml  390) pitfalls but

en/volunteer.wml  391) possibly have new methods in mind for implementing decloaking issues. The
en/volunteer.wml  392) website should ensure that it tells a user what their problem is. It
en/volunteer.wml  393) should help them to fix the problem or direct them to the proper support

en/volunteer.wml  394) channels. The student should be closely familiar with using Tor and how
en/volunteer.wml  395) to prevent Tor information leakage.

en/volunteer.wml  396) </li>
en/volunteer.wml  397) 

en/volunteer.wml  398) <li>

en/volunteer.wml  399) <b>Improving Tor's ability to resist censorship</b>

en/volunteer.wml  400) <br />

en/volunteer.wml  401) Priority: <i>High</i>
en/volunteer.wml  402) <br />
en/volunteer.wml  403) Effort Level: <i>High</i>
en/volunteer.wml  404) <br />

en/volunteer.wml  405) Skill Level: <i>High</i>

en/volunteer.wml  406) <br />

en/volunteer.wml  407) Likely Mentors: <i>Nick</i>

en/volunteer.wml  408) <br />

en/volunteer.wml  409) The Tor 0.2.0.x series makes <a
en/volunteer.wml  410) href="<svnsandbox>doc/design-paper/blocking.html">significant
en/volunteer.wml  411) improvements</a> in resisting national and organizational censorship.

en/volunteer.wml  412) But Tor still needs better mechanisms for some parts of its

en/volunteer.wml  413) anti-censorship design.  For example, current Tors can only listen on a
en/volunteer.wml  414) single address/port combination at a time.  There's
en/volunteer.wml  415) <a href="<svnsandbox>doc/spec/proposals/118-multiple-orports.txt">a

en/volunteer.wml  416) proposal to address this limitation</a> and allow clients to connect

en/volunteer.wml  417) to any given Tor on multiple addresses and ports, but it needs more
en/volunteer.wml  418) work.  Another anti-censorship project (far more difficult) is to try
en/volunteer.wml  419) to make Tor more scanning-resistant.  Right now, an adversary can identify

en/volunteer.wml  420) <a href="<svnsandbox>doc/spec/proposals/125-bridges.txt">Tor bridges</a>

en/volunteer.wml  421) just by trying to connect to them, following the Tor protocol, and 
en/volunteer.wml  422) seeing if they respond.  To solve this, bridges could
en/volunteer.wml  423) <a href="<svnsandbox>doc/design-paper/blocking.html#tth_sEc9.3">act like
en/volunteer.wml  424) webservers</a> (HTTP or HTTPS) when contacted by port-scanning tools,
en/volunteer.wml  425) and not act like bridges until the user provides a bridge-specific key.

en/volunteer.wml  426) <br />
en/volunteer.wml  427) This project involves a lot of research and design. One of the big
en/volunteer.wml  428) challenges will be identifying and crafting approaches that can still
en/volunteer.wml  429) resist an adversary even after the adversary knows the design, and
en/volunteer.wml  430) then trading off censorship resistance with usability and robustness.

en/volunteer.wml  431) </li>
en/volunteer.wml  432) 
en/volunteer.wml  433) <li>

en/volunteer.wml  434) <b>Libevent and Tor integration improvements</b>
en/volunteer.wml  435) <br />

en/volunteer.wml  436) Priority: <i>Medium</i>
en/volunteer.wml  437) <br />
en/volunteer.wml  438) Effort Level: <i>High</i>
en/volunteer.wml  439) <br />
en/volunteer.wml  440) Skill Level: <i>Medium to High</i>
en/volunteer.wml  441) <br />

en/volunteer.wml  442) Likely Mentors: <i>Nick</i>

en/volunteer.wml  443) <br />

en/volunteer.wml  444) Tor should make better use of the more recent features of Niels
en/volunteer.wml  445) Provos's <a href="http://monkey.org/~provos/libevent/">Libevent</a>

en/volunteer.wml  446) library.  Tor already uses Libevent for its low-level asynchronous IO

en/volunteer.wml  447) calls, and could also use Libevent's increasingly good implementations

en/volunteer.wml  448) of network buffers and of HTTP.  This wouldn't be simply a matter of

en/volunteer.wml  449) replacing Tor's internal calls with calls to Libevent: instead, we'll

en/volunteer.wml  450) need to refactor Tor to use Libevent calls that do not follow the

en/volunteer.wml  451) same models as Tor's existing backends. Also, we'll need to add
en/volunteer.wml  452) missing functionality to Libevent as needed — most difficult likely
en/volunteer.wml  453) will be adding OpenSSL support on top of Libevent's buffer abstraction.
en/volunteer.wml  454) Also tricky will be adding rate-limiting to Libevent.

en/volunteer.wml  455) </li>
en/volunteer.wml  456) 
en/volunteer.wml  457) <li>

en/volunteer.wml  458) <b>Tuneup Tor!</b>
en/volunteer.wml  459) <br />

en/volunteer.wml  460) Priority: <i>Medium</i>
en/volunteer.wml  461) <br />
en/volunteer.wml  462) Effort Level: <i>Medium</i>
en/volunteer.wml  463) <br />
en/volunteer.wml  464) Skill Level: <i>Medium to High</i>
en/volunteer.wml  465) <br />

en/volunteer.wml  466) Likely Mentors: <i>Nick, Roger, Mike</i>

en/volunteer.wml  467) <br />

en/volunteer.wml  468) Right now, Tor relays measure and report their own bandwidth, and Tor
en/volunteer.wml  469) clients choose which relays to use in part based on that bandwidth.
en/volunteer.wml  470) This approach is vulnerable to
en/volunteer.wml  471) <a href="http://freehaven.net/anonbib/#bauer:wpes2007">attacks where
en/volunteer.wml  472) relays lie about their bandwidth</a>;
en/volunteer.wml  473) to address this, Tor currently caps the maximum bandwidth
en/volunteer.wml  474) it's willing to believe any relay provides.  This is a limited fix, and
en/volunteer.wml  475) a waste of bandwidth capacity to boot.  Instead,

en/volunteer.wml  476) Tor should possibly measure bandwidth in a more distributed way, perhaps
en/volunteer.wml  477) as described in the

en/volunteer.wml  478) <a href="http://freehaven.net/anonbib/author.html#snader08">"A Tune-up for
en/volunteer.wml  479) Tor"</a> paper

en/volunteer.wml  480) by Snader and Borisov. A student could use current testing code to

en/volunteer.wml  481) double-check this paper's findings and verify the extent to which they

en/volunteer.wml  482) dovetail with Tor as deployed in the wild, and determine good ways to
en/volunteer.wml  483) incorporate them into their suggestions Tor network without adding too

en/volunteer.wml  484) much communications overhead between relays and directory

en/volunteer.wml  485) authorities.

en/volunteer.wml  486) </li>
en/volunteer.wml  487) 

en/volunteer.wml  488) <!--

en/volunteer.wml  489) <li>

en/volunteer.wml  490) <b>Improving the Tor QA process: Continuous Integration for Windows builds</b>
en/volunteer.wml  491) <br />

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

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

en/volunteer.wml  499) <br />

en/volunteer.wml  500) It would be useful to have automated build processes for Windows and
en/volunteer.wml  501) probably other platforms. The purpose of having a continuous integration
en/volunteer.wml  502) build environment is to ensure that Windows isn't left behind for any of
en/volunteer.wml  503) the software projects used in the Tor project or its accompanying.<br />
en/volunteer.wml  504) Buildbot may be a good choice for this as it appears to support all of
en/volunteer.wml  505) the platforms Tor does. See the 

en/volunteer.wml  506) <a href="http://en.wikipedia.org/wiki/BuildBot">wikipedia entry for

en/volunteer.wml  507) buildbot</a>.<br />
en/volunteer.wml  508) There may be better options and the person undertaking this task should
en/volunteer.wml  509) evaluate other options. Any person working on this automatic build
en/volunteer.wml  510) process should have experience or be willing to learn how to build all
en/volunteer.wml  511) of the respective Tor related code bases from scratch. Furthermore, the
en/volunteer.wml  512) person should have some experience building software in Windows
en/volunteer.wml  513) environments as this is the target audience we want to ensure we do not
en/volunteer.wml  514) leave behind. It would require close work with the Tor source code but

en/volunteer.wml  515) probably only in the form of building, not authoring.<br />
en/volunteer.wml  516) Additionally, we need to automate our performance testing for all platforms.
en/volunteer.wml  517) We've got buildbot (except on Windows &mdash; as noted above) to automate 
en/volunteer.wml  518) our regular integration and compile testing already,
en/volunteer.wml  519) but we need to get our network simulation tests (as built in torflow)
en/volunteer.wml  520) updated for more recent versions of Tor, and designed to launch a test
en/volunteer.wml  521) network either on a single machine, or across several, so we can test

en/volunteer.wml  522) changes in performance on machines in different roles automatically.

en/volunteer.wml  523) </li>

en/volunteer.wml  524) -->

en/volunteer.wml  525) 

en/volunteer.wml  526) <li>

en/volunteer.wml  527) <b>Improve our unit testing process</b>
en/volunteer.wml  528) <br />

en/volunteer.wml  529) Priority: <i>Medium</i>
en/volunteer.wml  530) <br />
en/volunteer.wml  531) Effort Level: <i>Medium</i>
en/volunteer.wml  532) <br />
en/volunteer.wml  533) Skill Level: <i>Medium</i>
en/volunteer.wml  534) <br />

en/volunteer.wml  535) Likely Mentors: <i>Nick</i>

en/volunteer.wml  536) <br />

en/volunteer.wml  537) Tor needs to be far more tested. This is a multi-part effort. To start

en/volunteer.wml  538) with, our unit test coverage should rise substantially, especially in

en/volunteer.wml  539) the areas outside the utility functions. This will require significant

en/volunteer.wml  540) refactoring of some parts of Tor, in order to dissociate as much logic

en/volunteer.wml  541) as possible from globals.
en/volunteer.wml  542) <br />

en/volunteer.wml  543) Additionally, we need to automate our performance testing. We've got

en/volunteer.wml  544) buildbot to automate our regular integration and compile testing already
en/volunteer.wml  545) (though we need somebody to set it up on Windows),
en/volunteer.wml  546) but we need to get our network simulation tests (as built in TorFlow: see
en/volunteer.wml  547) the "Tor Node Scanner improvements" item)

en/volunteer.wml  548) updated for more recent versions of Tor, and designed to launch a test
en/volunteer.wml  549) network either on a single machine, or across several, so we can test

en/volunteer.wml  550) changes in performance on machines in different roles automatically.

en/volunteer.wml  551) </li>
en/volunteer.wml  552) 

en/volunteer.wml  553) <li>

en/volunteer.wml  554) <b>Help revive an independent Tor client implementation</b>

en/volunteer.wml  555) <br />

en/volunteer.wml  556) Priority: <i>Medium</i>

en/volunteer.wml  557) <br />
en/volunteer.wml  558) Effort Level: <i>High</i>
en/volunteer.wml  559) <br />
en/volunteer.wml  560) Skill Level: <i>Medium to High</i>
en/volunteer.wml  561) <br />

en/volunteer.wml  562) Likely Mentors: <i>Karsten, Nick</i>

en/volunteer.wml  563) <br />

en/volunteer.wml  564) Reanimate one of the approaches to implement a Tor client in Java,
en/volunteer.wml  565) e.g. the <a href="http://onioncoffee.sourceforge.net/">OnionCoffee
en/volunteer.wml  566) project</a>, and make it run on <a
en/volunteer.wml  567) href="http://code.google.com/android/">Android</a>. The first step
en/volunteer.wml  568) would be to port the existing code and execute it in an Android
en/volunteer.wml  569) environment. Next, the code should be updated to support the newer Tor
en/volunteer.wml  570) protocol versions like the <a href="<svnsandbox>doc/spec/dir-spec.txt">v3
en/volunteer.wml  571) directory protocol</a>. Further, support for requesting or even

en/volunteer.wml  572) providing Tor hidden services would be neat, but not required.
en/volunteer.wml  573) <br />
en/volunteer.wml  574) The student should be able to understand and write new Java code, including

en/volunteer.wml  575) a Java cryptography API. Being able to read C code would be helpful,

en/volunteer.wml  576) too. The student should be willing to read the existing documentation,

en/volunteer.wml  577) implement code based on it, and refine the documentation
en/volunteer.wml  578) when things are underdocumented. This project is mostly about coding and

en/volunteer.wml  579) to a small degree about design.
en/volunteer.wml  580) </li>
en/volunteer.wml  581) 
en/volunteer.wml  582) <li>

en/volunteer.wml  583) <b>Automatic system tests and automatically starting private Tor networks</b>

en/volunteer.wml  584) <br />

en/volunteer.wml  585) Priority: <i>Medium</i>
en/volunteer.wml  586) <br />
en/volunteer.wml  587) Effort Level: <i>Medium</i>
en/volunteer.wml  588) <br />
en/volunteer.wml  589) Skill Level: <i>Medium</i>
en/volunteer.wml  590) <br />

en/volunteer.wml  591) Likely Mentors: <i>Karsten, Nick, Roger</i>

en/volunteer.wml  592) <br />

en/volunteer.wml  593) Write a tool that runs automatic system tests in addition
en/volunteer.wml  594) to the existing unit tests. The Java-based Tor simulator <a
en/volunteer.wml  595) href="https://tor-svn.freehaven.net/svn/puppetor/trunk/">PuppeTor</a>
en/volunteer.wml  596) might be a good start for starting up a private Tor network, using it
en/volunteer.wml  597) for a while, and verifying that at least parts of it are working. This
en/volunteer.wml  598) project requires to conceive a blueprint for performing system tests
en/volunteer.wml  599) of private Tor networks, before starting to code. Typical types of
en/volunteer.wml  600) tests range from performing single requests over the private network to
en/volunteer.wml  601) manipulating exchanged messages and see if nodes handle corrupt messages

en/volunteer.wml  602) appropriately.
en/volunteer.wml  603) <br />
en/volunteer.wml  604) The student should be able to obtain a good understanding

en/volunteer.wml  605) of how Tor works and what problems and bugs could arise to design good

en/volunteer.wml  606) test cases. Understanding the existing Tor code structure and documentation is

en/volunteer.wml  607) vital. If PuppeTor is used, the student should also be able to understand
en/volunteer.wml  608) and possibly extend an existing Java application. This project is partly
en/volunteer.wml  609) about design and partly about coding.
en/volunteer.wml  610) </li>
en/volunteer.wml  611) 
en/volunteer.wml  612) <li>

en/volunteer.wml  613) <b>Bring moniTor to life</b>
en/volunteer.wml  614) <br />

en/volunteer.wml  615) Priority: <i>Medium</i>
en/volunteer.wml  616) <br />
en/volunteer.wml  617) Effort Level: <i>Medium</i>
en/volunteer.wml  618) <br />
en/volunteer.wml  619) Skill Level: <i>Low to Medium</i>
en/volunteer.wml  620) <br />

en/volunteer.wml  621) Likely Mentors: <i>Karsten, Jacob</i>

en/volunteer.wml  622) <br />

en/volunteer.wml  623) Implement a <a href="http://www.ss64.com/bash/top.html">top-like</a>
en/volunteer.wml  624) management tool for Tor relays. The purpose of such a tool would be
en/volunteer.wml  625) to monitor a local Tor relay via its control port and include useful
en/volunteer.wml  626) system information of the underlying machine. When running this tool, it
en/volunteer.wml  627) would dynamically update its content like top does for Linux processes.
en/volunteer.wml  628) <a href="http://archives.seul.org/or/dev/Jan-2008/msg00005.html">This

en/volunteer.wml  629) or-dev post</a> might be a good first read.
en/volunteer.wml  630) <br />
en/volunteer.wml  631) The student should be familiar

en/volunteer.wml  632) with or willing to learn about administering a Tor relay and configuring
en/volunteer.wml  633) it via its control port. As an initial prototype is written in Python,
en/volunteer.wml  634) some knowledge about writing Python code would be helpful, too. This

en/volunteer.wml  635) project is one part about identifying requirements to such a
en/volunteer.wml  636) tool and designing its interface, and one part lots of coding.

en/volunteer.wml  637) </li>
en/volunteer.wml  638) 

en/volunteer.wml  639) <li>

en/volunteer.wml  640) <b>Tor Exit Scanner improvements</b>

en/volunteer.wml  641) <br />
en/volunteer.wml  642) Priority: <i>High</i>
en/volunteer.wml  643) <br />
en/volunteer.wml  644) Effort Level: <i>High</i>
en/volunteer.wml  645) <br />

en/volunteer.wml  646) Skill Level: <i>High</i>
en/volunteer.wml  647) <br />

en/volunteer.wml  648) Likely Mentors: <i>Mike</i>

en/volunteer.wml  649) <br />
en/volunteer.wml  650) The Tor exit node scanner 'SoaT', part of the <a

en/volunteer.wml  651) href="<svnsandbox>torflow/">Torflow project</a>, makes connections out
en/volunteer.wml  652) of each Tor exit node and compares the content it gets back with what it
en/volunteer.wml  653) "should" get back. The goal is to notice misconfigured, broken, and even
en/volunteer.wml  654) malicious exit relays. Alas, the code is

en/volunteer.wml  655) currently written in rather rickety perl and relies on MD5sums of
en/volunteer.wml  656) entire documents in order to determine if exit nodes are modifying
en/volunteer.wml  657) content. The problem with this is threefold: 1) Perl sucks at life.
en/volunteer.wml  658) 2) The scanner can't verify pages that are dynamic, and attackers can
en/volunteer.wml  659) focus malicious content injection on only those dynamic pages. 3)
en/volunteer.wml  660) Pages change after a while (or based on GeoIP) and begin generating
en/volunteer.wml  661) false positives.
en/volunteer.wml  662) <br />
en/volunteer.wml  663) Ideally, soat.pl would be reimplemented in a sane language with a

en/volunteer.wml  664) robust html parser library (since the rest of Torflow is in Python
en/volunteer.wml  665) that would be nice, but it is not required), and calculate signatures only for

en/volunteer.wml  666) tags and content likely to be targeted by a malicious attacker (script

en/volunteer.wml  667) tags, object links, images, css). It should also be robust in the face of

en/volunteer.wml  668) changes to content outside of Tor, and ultimately even GeoIP localized
en/volunteer.wml  669) content.
en/volunteer.wml  670) <br />

en/volunteer.wml  671) This scanner would likely be run by the Directory Authorities and

en/volunteer.wml  672) report its results to the control port via the AuthDirBadExit config
en/volunteer.wml  673) setting.
en/volunteer.wml  674) <br />
en/volunteer.wml  675) </li>

en/volunteer.wml  676) 

en/volunteer.wml  677) <li>

en/volunteer.wml  678) <b>Tor Node Scanner improvements</b>

en/volunteer.wml  679) <br />

en/volunteer.wml  680) Priority: <i>High</i>

en/volunteer.wml  681) <br />

en/volunteer.wml  682) Effort Level: <i>Medium to High</i>

en/volunteer.wml  683) <br />

en/volunteer.wml  684) Skill Level: <i>Medium to High</i>

en/volunteer.wml  685) <br />

en/volunteer.wml  686) Likely Mentors: <i>Mike</i>

en/volunteer.wml  687) <br />
en/volunteer.wml  688) Similar to the exit scanner (or perhaps even during exit scanning),
en/volunteer.wml  689) statistics can be gathered about the reliability of nodes. Nodes that

en/volunteer.wml  690) fail too high a percentage of their circuits should not be given
en/volunteer.wml  691) Guard status. Perhaps they should have their reported bandwidth

en/volunteer.wml  692) penalized by some ratio as well, or just get marked as Invalid. In
en/volunteer.wml  693) addition, nodes that exhibit a very low average stream capacity but
en/volunteer.wml  694) advertise a very high node bandwidth can also be marked as Invalid.
en/volunteer.wml  695) Much of this statistics gathering is already done, it just needs to be
en/volunteer.wml  696) transformed into something that can be reported to the Directory
en/volunteer.wml  697) Authorities to blacklist/penalize nodes in such a way that clients
en/volunteer.wml  698) will listen.
en/volunteer.wml  699) <br />
en/volunteer.wml  700) In addition, these same statistics can be gathered about the traffic
en/volunteer.wml  701) through a node. Events can be added to the <a
en/volunteer.wml  702) href="https://www.torproject.org/svn/torctl/doc/howto.txt">Tor Control
en/volunteer.wml  703) Protocol</a> to

en/volunteer.wml  704) report if a circuit extend attempt through the node succeeds or fails, and

en/volunteer.wml  705) passive statistics can be gathered on both bandwidth and reliability
en/volunteer.wml  706) of other nodes via a node-based monitor using these events. Such a

en/volunteer.wml  707) scanner would also report information on oddly-behaving nodes to

en/volunteer.wml  708) the Directory Authorities, but a communication channel for this
en/volunteer.wml  709) currently does not exist and would need to be developed as well.
en/volunteer.wml  710) </li>

en/volunteer.wml  711) 
en/volunteer.wml  712) <li>
en/volunteer.wml  713) <b>Help track the overall Tor Network status</b>
en/volunteer.wml  714) <br />
en/volunteer.wml  715) Priority: <i>High</i>
en/volunteer.wml  716) <br />
en/volunteer.wml  717) Effort Level: <i>Medium</i>
en/volunteer.wml  718) <br />
en/volunteer.wml  719) Skill Level: <i>Medium</i>
en/volunteer.wml  720) <br />
en/volunteer.wml  721) Likely Mentors: <i>Roger, Nick, Mike</i>
en/volunteer.wml  722) <br />
en/volunteer.wml  723) It would be great to set up an automated system for tracking network
en/volunteer.wml  724) health over time, graphing it, etc. Part of this project would involve
en/volunteer.wml  725) inventing better metrics for assessing network health and growth. Is the
en/volunteer.wml  726) average uptime of the network increasing? How many relays are qualifying
en/volunteer.wml  727) for Guard status this month compared to last month? What's the turnover
en/volunteer.wml  728) in terms of new relays showing up and relays shutting off? Periodically
en/volunteer.wml  729) people collect brief snapshots, but where it gets really interesting is
en/volunteer.wml  730) when we start tracking data points over time.
en/volunteer.wml  731) <br />
en/volunteer.wml  732) Data could be collected from the "Tor Node Scanner" item above, from
en/volunteer.wml  733) the server descriptors that each relay publishes, and from other
en/volunteer.wml  734) sources. Results over time could be integrated into one of the <a
en/volunteer.wml  735) href="https://torstatus.blutmagie.de/">Tor Status</a> web pages, or be
en/volunteer.wml  736) kept separate. Speaking of the Tor Status pages, take a look at Roger's
en/volunteer.wml  737) <a href="http://archives.seul.org/or/talk/Jan-2008/msg00300.html">Tor
en/volunteer.wml  738) Status wish list</a>.
en/volunteer.wml  739) </li>
en/volunteer.wml  740) 

en/volunteer.wml  741) <li>
en/volunteer.wml  742) <b>Tor path selection improvements</b>
en/volunteer.wml  743) <br />
en/volunteer.wml  744) Priority: <i>High</i>
en/volunteer.wml  745) <br />

en/volunteer.wml  746) Effort Level: <i>Low to Medium</i>

en/volunteer.wml  747) <br />

en/volunteer.wml  748) Skill Level: <i>High</i>
en/volunteer.wml  749) <br />
en/volunteer.wml  750) Likely Mentors: <i>Roger, Nick, Mike</i>

en/volunteer.wml  751) <br />
en/volunteer.wml  752) Some simple improvements can be made to Tor's path selection to vastly
en/volunteer.wml  753) improve Tor speed. For instance, some of the (unofficial) <a
en/volunteer.wml  754) href="http://wiki.noreply.org/noreply/TheOnionRouter/FireFoxTorPerf">Tor
en/volunteer.wml  755) Performance Recommendations</a> on the wiki are to increase the number of
en/volunteer.wml  756) guards and decrease the CircuitBuildTimeout. Ideally, the client would

en/volunteer.wml  757) <a href="http://archives.seul.org/or/talk/Feb-2008/msg00012.html">learn
en/volunteer.wml  758) these values by gathering statistics on circuit construction
en/volunteer.wml  759) time</a> (and/or using values gained from Torflow), and set the timeouts

en/volunteer.wml  760) low enough such that some high percentile (75%, 90%, 1-stddev?) of
en/volunteer.wml  761) circuits succeed, yet extremely slow nodes are avoided. This would
en/volunteer.wml  762) involve some statistics gathering+basic research, and some changes to 
en/volunteer.wml  763) Tor path selection code.
en/volunteer.wml  764) <br />
en/volunteer.wml  765) In addition, to improve path security, some elements from the <a
en/volunteer.wml  766) href="http://www.torproject.org/svn/trunk/doc/spec/proposals/115-two-hop-paths.txt">Two
en/volunteer.wml  767) Hop Paths proposal</a> could be done as part of this (since it will
en/volunteer.wml  768) likely touch the same code anyways), regardless of the adoption of

en/volunteer.wml  769) that proposal. In particular, clients probably should avoid guards that
en/volunteer.wml  770) seem to fail an excessive percentage of their circuits through them,
en/volunteer.wml  771) and non-firewalled clients should issue a warning if they are only able
en/volunteer.wml  772) to connect to a limited set of guard nodes. See also
en/volunteer.wml  773) <a href="http://archives.seul.org/or/dev/Feb-2008/msg00003.html">this
en/volunteer.wml  774) or-dev post</a>.

en/volunteer.wml  775) </li>

en/volunteer.wml  776) 

en/volunteer.wml  777) <li>
en/volunteer.wml  778) <b>Torbutton improvements</b>
en/volunteer.wml  779) <br />

en/volunteer.wml  780) Priority: <i>Medium</i>

en/volunteer.wml  781) <br />

en/volunteer.wml  782) Effort Level: <i>High</i>
en/volunteer.wml  783) <br />
en/volunteer.wml  784) Skill Level: <i>High</i>

en/volunteer.wml  785) <br />

en/volunteer.wml  786) Likely Mentors: <i>Mike</i>

en/volunteer.wml  787) <br/>
en/volunteer.wml  788) Torbutton has a number of improvements that can be made in the post-1.2
en/volunteer.wml  789) timeframe. Most of these are documented as feature requests in the <a
en/volunteer.wml  790) href="https://bugs.torproject.org/flyspray/index.php?tasks=all&project=5">Torbutton
en/volunteer.wml  791) flyspray section</a>. Good examples include: stripping off node.exit on http
en/volunteer.wml  792) headers, more fine-grained control over formfill blocking, improved referrer

en/volunteer.wml  793) spoofing based on the domain of the site (a-la <a
en/volunteer.wml  794) href="http://addons.mozilla.org/firefox/addon/4513">refspoof extension</a>),
en/volunteer.wml  795) tighter integration with Vidalia for reporting Tor status, a New Identity
en/volunteer.wml  796) button with Tor integration and multiple identity management, and anything

en/volunteer.wml  797) else you might think of.

en/volunteer.wml  798) <br />
en/volunteer.wml  799) This work would be independent coding in Javascript and the fun world of <a
en/volunteer.wml  800) href="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">XUL</a>,
en/volunteer.wml  801) with not too much involvement in the Tor internals.

en/volunteer.wml  802) </li>
en/volunteer.wml  803) 

en/volunteer.wml  804) <li>

en/volunteer.wml  805) <b>Porting Polipo to Windows</b>
en/volunteer.wml  806) <br />

en/volunteer.wml  807) Priority: <i>Medium</i>

en/volunteer.wml  808) <br />

en/volunteer.wml  809) Effort Level: <i>Medium</i>

en/volunteer.wml  810) <br />
en/volunteer.wml  811) Skill Level: <i>Medium to High</i>
en/volunteer.wml  812) <br />

en/volunteer.wml  813) Likely Mentors: <i>Andrew, Steven, Roger</i>

en/volunteer.wml  814) <br />

en/volunteer.wml  815) Help port <a
en/volunteer.wml  816) href="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</a> to

en/volunteer.wml  817) Windows. Example topics to tackle include:
en/volunteer.wml  818) 1) handle spaces in path names and understand the filesystem
en/volunteer.wml  819) namespace — that is, where application data, personal data,

en/volunteer.wml  820) and program data typically reside in various versions of Windows. 2) the
en/volunteer.wml  821) ability to handle ipv6 communications. 3) the ability to asynchronously
en/volunteer.wml  822) query name servers, find the system nameservers, and manage netbios
en/volunteer.wml  823) and dns queries. 4) use native regex capabilities of Windows, rather
en/volunteer.wml  824) than using 3rd party GNU regex libraries. 5) manage events and buffers
en/volunteer.wml  825) natively (i.e. in Unix-like OSes, Polipo defaults to 25% of ram, in
en/volunteer.wml  826) Windows it's whatever the config specifies). 6) some sort of GUI config
en/volunteer.wml  827) and reporting tool, bonus if it has a systray icon with right clickable
en/volunteer.wml  828) menu options. Double bonus if it's cross-platform compatible.
en/volunteer.wml  829) </li>
en/volunteer.wml  830) 
en/volunteer.wml  831) <li>

en/volunteer.wml  832) <b>Make our diagrams beautiful and automated</b>

en/volunteer.wml  833) <br />

en/volunteer.wml  834) Priority: <i>Medium</i>

en/volunteer.wml  835) <br />
en/volunteer.wml  836) Effort Level: <i>Low</i>
en/volunteer.wml  837) <br />
en/volunteer.wml  838) Skill Level: <i>Low</i>
en/volunteer.wml  839) <br />

en/volunteer.wml  840) Likely Mentors: <i>Andrew</i>

en/volunteer.wml  841) <br />

en/volunteer.wml  842) We need a way to generate the website diagrams (for example, the "How
en/volunteer.wml  843) Tor Works" pictures on the <a href="<page overview>">overview page</a>
en/volunteer.wml  844) from source, so we can translate them as UTF-8 text rather than edit
en/volunteer.wml  845) them by hand with Gimp. We might want to
en/volunteer.wml  846) integrate this as an wml file so translations are easy and images are
en/volunteer.wml  847) generated in multiple languages whenever we build the website. See the
en/volunteer.wml  848) "Translation Wiki" idea above.

en/volunteer.wml  849) </li>
en/volunteer.wml  850) 

en/volunteer.wml  851) <li>
en/volunteer.wml  852) <b>Improve the LiveCD offerings for the Tor community</b>
en/volunteer.wml  853) <br />

en/volunteer.wml  854) Priority: <i>Low</i>
en/volunteer.wml  855) <br />
en/volunteer.wml  856) Effort Level: <i>Low</i>
en/volunteer.wml  857) <br />
en/volunteer.wml  858) Skill Level: <i>Medium to High</i>
en/volunteer.wml  859) <br />

en/volunteer.wml  860) Likely Mentors: <i>Anonym, Jacob, Roger</i>

en/volunteer.wml  861) <br />

en/volunteer.wml  862) How can we make the <a

en/volunteer.wml  863) href="http://anonymityanywhere.com/incognito/">Incognito LiveCD</a>

en/volunteer.wml  864) easier to maintain, improve, and document?
en/volunteer.wml  865) </li>

en/volunteer.wml  866) 

en/volunteer.wml  867) <li>
en/volunteer.wml  868) <b>Rework and extend Blossom</b>
en/volunteer.wml  869) <br />
en/volunteer.wml  870) Priority: <i>Medium</i>
en/volunteer.wml  871) <br />
en/volunteer.wml  872) Effort Level: <i>Medium to High</i>
en/volunteer.wml  873) <br />
en/volunteer.wml  874) Skill Level: <i>Medium to High</i>
en/volunteer.wml  875) <br />
en/volunteer.wml  876) Likely Mentors: <i>Goodell</i>
en/volunteer.wml  877) <br />
en/volunteer.wml  878) Rework and extend Blossom (a tool for monitoring and
en/volunteer.wml  879) selecting appropriate Tor circuits based upon exit node requirements
en/volunteer.wml  880) specified by the user) to gather data in a self-contained way, with
en/volunteer.wml  881) parameters easily configurable by the user.  Blossom is presently
en/volunteer.wml  882) implemented as a single Python script that interfaces with Tor using the
en/volunteer.wml  883) Controller interface and depends upon metadata about Tor nodes obtained
en/volunteer.wml  884) via external processes, such as a webpage indicating status of the nodes
en/volunteer.wml  885) plus publically available data from DNS, whois, etc.  This project has
en/volunteer.wml  886) two parts: (1) Determine which additional metadata may be useful and
en/volunteer.wml  887) rework Blossom so that it cleanly obtains the metadata on its own rather
en/volunteer.wml  888) than depend upon external scripts (this may, for example, involve
en/volunteer.wml  889) additional threads or inter-process communication), and (2) develop a
en/volunteer.wml  890) means by which the user can easily configure Blossom, starting with a
en/volunteer.wml  891) configuration file and possibly working up to a web configuration engine.

en/volunteer.wml  892) Knowledge of Tor and Python are important; knowledge of
en/volunteer.wml  893) TCP, interprocess communication, and Perl will also be helpful.  An
en/volunteer.wml  894) interest in network neutrality is important as well, since the
en/volunteer.wml  895) principles of evaluating and understanding internet inconsistency are at
en/volunteer.wml  896) the core of the Blossom effort.

en/volunteer.wml  897) </li>
en/volunteer.wml  898) 
en/volunteer.wml  899) <li>
en/volunteer.wml  900) <b>Improve Blossom: Allow users to qualitatively describe exit nodes they desire</b>
en/volunteer.wml  901) <br />
en/volunteer.wml  902) Priority: <i>Low</i>
en/volunteer.wml  903) <br />
en/volunteer.wml  904) Effort Level: <i>Medium</i>
en/volunteer.wml  905) <br />
en/volunteer.wml  906) Skill Level: <i>Medium</i>
en/volunteer.wml  907) <br />
en/volunteer.wml  908) Likely Mentors: <i>Goodell</i>
en/volunteer.wml  909) <br />
en/volunteer.wml  910) Develop and implement a means of affording Blossom
en/volunteer.wml  911) users the ability to qualitatively describe the exit node that they
en/volunteer.wml  912) want.  The Internet is an inconsistent place: some Tor exit nodes see
en/volunteer.wml  913) the world differently than others.  As presently implemented, Blossom (a
en/volunteer.wml  914) tool for monitoring and selecting appropriate Tor circuits based upon
en/volunteer.wml  915) exit node requirements specified by the user) lacks a sufficiently rich
en/volunteer.wml  916) language to describe how the different vantage points are different.
en/volunteer.wml  917) For example, some exit nodes may have an upstream network that filters
en/volunteer.wml  918) certain kinds of traffic or certain websites.  Other exit nodes may
en/volunteer.wml  919) provide access to special content as a result of their location, perhaps
en/volunteer.wml  920) as a result of discrimination on the part of the content providers
en/volunteer.wml  921) themselves.  This project has two parts: (1) develop a language for
en/volunteer.wml  922) describing characteristics of networks in which exit nodes reside, and
en/volunteer.wml  923) (2) incorporate this language into Blossom so that users can select Tor
en/volunteer.wml  924) paths based upon the description.

en/volunteer.wml  925) Knowledge of Tor and Python are important; knowledge of
en/volunteer.wml  926) TCP, interprocess communication, and Perl will also be helpful.  An
en/volunteer.wml  927) interest in network neutrality is important as well, since the
en/volunteer.wml  928) principles of evaluating and understanding internet inconsistency are at
en/volunteer.wml  929) the core of the Blossom effort.

en/volunteer.wml  930) </li>
en/volunteer.wml  931) 

en/volunteer.wml  932) <li>
en/volunteer.wml  933) <b>Bring up new ideas!</b>
en/volunteer.wml  934) <br />
en/volunteer.wml  935) Don't like any of these? Look at the <a

en/volunteer.wml  936) href="<svnsandbox>doc/design-paper/roadmap-future.pdf">Tor development

en/volunteer.wml  937) roadmap</a> for more ideas.
en/volunteer.wml  938) </li>
en/volunteer.wml  939) 

en/volunteer.wml  940) </ol>
en/volunteer.wml  941) 

en/volunteer.wml  942) <h2><a class="anchor" href="#Coding">Coding and Design</a></h2>

volunteer.html    943) <ol>

en/volunteer.wml  944) <li>Tor relays don't work well on Windows XP. On

en/volunteer.wml  945) Windows, Tor uses the standard <tt>select()</tt> system

en/volunteer.wml  946) call, which uses space in the non-page pool. This means

en/volunteer.wml  947) that a medium sized Tor relay will empty the non-page pool, <a

en/volunteer.wml  948) href="https://wiki.torproject.org/noreply/TheOnionRouter/WindowsBufferProblems">causing

en/volunteer.wml  949) havoc and system crashes</a>. We should probably be using overlapped IO

en/volunteer.wml  950) instead. One solution would be to teach <a
en/volunteer.wml  951) href="http://www.monkey.org/~provos/libevent/">libevent</a> how to use
en/volunteer.wml  952) overlapped IO rather than select() on Windows, and then adapt Tor to

en/volunteer.wml  953) the new libevent interface. Christian King made a
en/volunteer.wml  954) <a href="https://tor-svn.freehaven.net/svn/libevent-urz/trunk/">good

en/volunteer.wml  955) start</a> on this in the summer of 2007.</li>

en/volunteer.wml  956) <li>We need to actually start building our <a href="<page
en/volunteer.wml  957) documentation>#DesignDoc">blocking-resistance design</a>. This involves

en/volunteer.wml  958) fleshing out the design, modifying many different pieces of Tor, adapting
en/volunteer.wml  959) <a href="http://vidalia-project.net/">Vidalia</a> so it supports the
en/volunteer.wml  960) new features, and planning for deployment.</li>

en/volunteer.wml  961) <li>We need a flexible simulator framework for studying end-to-end
en/volunteer.wml  962) traffic confirmation attacks. Many researchers have whipped up ad hoc
en/volunteer.wml  963) simulators to support their intuition either that the attacks work
en/volunteer.wml  964) really well or that some defense works great. Can we build a simulator
en/volunteer.wml  965) that's clearly documented and open enough that everybody knows it's
en/volunteer.wml  966) giving a reasonable answer? This will spur a lot of new research.
en/volunteer.wml  967) See the entry <a href="#Research">below</a> on confirmation attacks for
en/volunteer.wml  968) details on the research side of this task &mdash; who knows, when it's
en/volunteer.wml  969) done maybe you can help write a paper or three also.</li>

en/volunteer.wml  970) <li>Tor 0.1.1.x and later include support for hardware crypto accelerators

en/volunteer.wml  971) via OpenSSL. Nobody has ever tested it, though. Does somebody want to get

volunteer.html    972) a card and let us know how it goes?</li>

volunteer.html    973) <li>Perform a security analysis of Tor with <a
volunteer.html    974) href="http://en.wikipedia.org/wiki/Fuzz_testing">"fuzz"</a>. Determine

en/volunteer.wml  975) if there are good fuzzing libraries out there for what we want. Win fame by

volunteer.html    976) getting credit when we put out a new release because of you!</li>

volunteer.html    977) <li>Tor uses TCP for transport and TLS for link
volunteer.html    978) encryption. This is nice and simple, but it means all cells
volunteer.html    979) on a link are delayed when a single packet gets dropped, and
volunteer.html    980) it means we can only reasonably support TCP streams. We have a <a

en/volunteer.wml  981) href="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#TransportIPnotTCP">list

en/volunteer.wml  982) of reasons why we haven't shifted to UDP transport</a>, but it would
en/volunteer.wml  983) be great to see that list get shorter. We also have a proposed <a

en/volunteer.wml  984) href="<svnsandbox>doc/spec/proposals/100-tor-spec-udp.txt">specification
en/volunteer.wml  985) for Tor and

en/volunteer.wml  986) UDP</a> &mdash; please let us know what's wrong with it.</li>

volunteer.html    987) <li>We're not that far from having IPv6 support for destination addresses
volunteer.html    988) (at exit nodes). If you care strongly about IPv6, that's probably the
volunteer.html    989) first place to start.</li>

volunteer.html    990) </ol>
volunteer.html    991) 

en/volunteer.wml  992) <a id="Research"></a>
en/volunteer.wml  993) <h2><a class="anchor" href="#Research">Research</a></h2>

volunteer.html    994) <ol>

volunteer.html    995) <li>The "website fingerprinting attack": make a list of a few
volunteer.html    996) hundred popular websites, download their pages, and make a set of
volunteer.html    997) "signatures" for each site. Then observe a Tor client's traffic. As
volunteer.html    998) you watch him receive data, you quickly approach a guess about which
volunteer.html    999) (if any) of those sites he is visiting. First, how effective is
volunteer.html   1000) this attack on the deployed Tor codebase? Then start exploring
volunteer.html   1001) defenses: for example, we could change Tor's cell size from 512
volunteer.html   1002) bytes to 1024 bytes, we could employ padding techniques like <a
volunteer.html   1003) href="http://freehaven.net/anonbib/#timing-fc2004">defensive dropping</a>,
volunteer.html   1004) or we could add traffic delays. How much of an impact do these have,
volunteer.html   1005) and how much usability impact (using some suitable metric) is there from
volunteer.html   1006) a successful defense in each case?</li>

volunteer.html   1007) <li>The "end-to-end traffic confirmation attack":
volunteer.html   1008) by watching traffic at Alice and at Bob, we can <a
volunteer.html   1009) href="http://freehaven.net/anonbib/#danezis:pet2004">compare
volunteer.html   1010) traffic signatures and become convinced that we're watching the same
volunteer.html   1011) stream</a>. So far Tor accepts this as a fact of life and assumes this
volunteer.html   1012) attack is trivial in all cases. First of all, is that actually true? How
volunteer.html   1013) much traffic of what sort of distribution is needed before the adversary
volunteer.html   1014) is confident he has won? Are there scenarios (e.g. not transmitting much)
volunteer.html   1015) that slow down the attack? Do some traffic padding or traffic shaping
volunteer.html   1016) schemes work better than others?</li>

en/volunteer.wml 1017) <li>A related question is: Does running a relay/bridge provide additional
en/volunteer.wml 1018) protection against these timing attacks? Can an external adversary that can't
en/volunteer.wml 1019) see inside TLS links still recognize individual streams reliably? 
en/volunteer.wml 1020) Does the amount of traffic carried degrade this ability any? What if the
en/volunteer.wml 1021) client-relay deliberately delayed upstream relayed traffic to create a queue
en/volunteer.wml 1022) that could be used to mimic timings of client downstream traffic to make it
en/volunteer.wml 1023) look like it was also relayed? This same queue could also be used for masking
en/volunteer.wml 1024) timings in client upstream traffic with the techniques from <a
en/volunteer.wml 1025) href="http://www.freehaven.net/anonbib/#ShWa-Timing06">adaptive padding</a>,
en/volunteer.wml 1026) but without the need for additional traffic. Would such an interleaving of
en/volunteer.wml 1027) client upstream traffic obscure timings for external adversaries? Would the
en/volunteer.wml 1028) strategies need to be adjusted for asymmetric links? For example, on
en/volunteer.wml 1029) asymmetric links, is it actually possible to differentiate client traffic from
en/volunteer.wml 1030) natural bursts due to their asymmetric capacity? Or is it easier than
en/volunteer.wml 1031) symmetric links for some other reason?</li>

volunteer.html   1032) <li>The "routing zones attack": most of the literature thinks of
volunteer.html   1033) the network path between Alice and her entry node (and between the
volunteer.html   1034) exit node and Bob) as a single link on some graph. In practice,
volunteer.html   1035) though, the path traverses many autonomous systems (ASes), and <a
volunteer.html   1036) href="http://freehaven.net/anonbib/#feamster:wpes2004">it's not uncommon
volunteer.html   1037) that the same AS appears on both the entry path and the exit path</a>.
volunteer.html   1038) Unfortunately, to accurately predict whether a given Alice, entry,
volunteer.html   1039) exit, Bob quad will be dangerous, we need to download an entire Internet
volunteer.html   1040) routing zone and perform expensive operations on it. Are there practical
volunteer.html   1041) approximations, such as avoiding IP addresses in the same /8 network?</li>

en/volunteer.wml 1042) <li>Other research questions regarding geographic diversity consider
en/volunteer.wml 1043) the tradeoff between choosing an efficient circuit and choosing a random

en/volunteer.wml 1044) circuit. Look at Stephen Rollyson's <a

en/volunteer.wml 1045) href="http://swiki.cc.gatech.edu:8080/ugResearch/uploads/7/ImprovingTor.pdf">position
en/volunteer.wml 1046) paper</a> on how to discard particularly slow choices without hurting

en/volunteer.wml 1047) anonymity "too much". This line of reasoning needs more work and more
en/volunteer.wml 1048) thinking, but it looks very promising.</li>

en/volunteer.wml 1049) <li>Tor doesn't work very well when relays have asymmetric bandwidth

volunteer.html   1050) (e.g. cable or DSL). Because Tor has separate TCP connections between
volunteer.html   1051) each hop, if the incoming bytes are arriving just fine and the outgoing
volunteer.html   1052) bytes are all getting dropped on the floor, the TCP push-back mechanisms
volunteer.html   1053) don't really transmit this information back to the incoming streams.
volunteer.html   1054) Perhaps Tor should detect when it's dropping a lot of outgoing packets,
volunteer.html   1055) and rate-limit incoming streams to regulate this itself? I can imagine
volunteer.html   1056) a build-up and drop-off scheme where we pick a conservative rate-limit,
volunteer.html   1057) slowly increase it until we get lost packets, back off, repeat. We
volunteer.html   1058) need somebody who's good with networks to simulate this and help design
volunteer.html   1059) solutions; and/or we need to understand the extent of the performance
volunteer.html   1060) degradation, and use this as motivation to reconsider UDP transport.</li>
volunteer.html   1061) <li>A related topic is congestion control. Is our
volunteer.html   1062) current design sufficient once we have heavy use? Maybe
volunteer.html   1063) we should experiment with variable-sized windows rather
volunteer.html   1064) than fixed-size windows? That seemed to go well in an <a
volunteer.html   1065) href="http://www.psc.edu/networking/projects/hpn-ssh/theory.php">ssh
volunteer.html   1066) throughput experiment</a>. We'll need to measure and tweak, and maybe
volunteer.html   1067) overhaul if the results are good.</li>

volunteer.html   1068) <li>To let dissidents in remote countries use Tor without being blocked
volunteer.html   1069) at their country's firewall, we need a way to get tens of thousands of
volunteer.html   1070) relays, not just a few hundred. We can imagine a Tor client GUI that

en/volunteer.wml 1071) has a "Tor for Freedom" button at the top that opens a port and relays a

volunteer.html   1072) few KB/s of traffic into the Tor network. (A few KB/s shouldn't be too
volunteer.html   1073) much hassle, and there are few abuse issues since they're not being exit
volunteer.html   1074) nodes.) But how do we distribute a list of these volunteer clients to the
volunteer.html   1075) good dissidents in an automated way that doesn't let the country-level

en/volunteer.wml 1076) firewalls intercept and enumerate them? This probably needs to work on a

en/volunteer.wml 1077) human-trust level. See our <a href="<page documentation>#DesignDoc">early
en/volunteer.wml 1078) blocking-resistance design document</a> and our
en/volunteer.wml 1079) <a

en/volunteer.wml 1080) href="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#BlockingResistance">FAQ

en/volunteer.wml 1081) entry</a> on this, and then read the <a
en/volunteer.wml 1082) href="http://freehaven.net/anonbib/topic.html#Communications_20Censorship">censorship
en/volunteer.wml 1083) resistance section of anonbib</a>.</li>

volunteer.html   1084) <li>Tor circuits are built one hop at a time, so in theory we have the
volunteer.html   1085) ability to make some streams exit from the second hop, some from the
volunteer.html   1086) third, and so on. This seems nice because it breaks up the set of exiting

en/volunteer.wml 1087) streams that a given relay can see. But if we want each stream to be safe,

volunteer.html   1088) the "shortest" path should be at least 3 hops long by our current logic, so
volunteer.html   1089) the rest will be even longer. We need to examine this performance / security
volunteer.html   1090) tradeoff.</li>

en/volunteer.wml 1091) <li>It's not that hard to DoS Tor relays or directory authorities. Are client

volunteer.html   1092) puzzles the right answer? What other practical approaches are there? Bonus
volunteer.html   1093) if they're backward-compatible with the current Tor protocol.</li>

volunteer.html   1094) </ol>
volunteer.html   1095) 

en/volunteer.wml 1096) <p>

en/volunteer.wml 1097) <a href="<page contact>">Let us know</a> if you've made progress on any
en/volunteer.wml 1098) of these!

en/volunteer.wml 1099) </p>

volunteer.html   1100) 

en/volunteer.wml 1101)   </div><!-- #main -->

volunteer.html   1102) 

en/volunteer.wml 1103) #include <foot.wmi>