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volunteer.html     4) 

en/volunteer.wml   5) #include "head.wmi" TITLE="Tor: Volunteer"

volunteer.html     6) 
volunteer.html     7) <div class="main-column">
volunteer.html     8) 
volunteer.html     9) <!-- PUT CONTENT AFTER THIS TAG -->

en/volunteer.wml  10) <h2>A few things everyone can do now:</h2>

volunteer.html    11) <ol>

en/volunteer.wml  12) <li>Please consider <a href="<page docs/tor-doc-relay>">running
en/volunteer.wml  13) a relay</a> to help the Tor network grow.</li>
en/volunteer.wml  14) <li>Tell your friends! Get them to run relays. Get them to run hidden

volunteer.html    15) services. Get them to tell their friends.</li>

en/volunteer.wml  16) <li>If you like Tor's goals, please <a href="<page donate>">take a moment
en/volunteer.wml  17) to donate to support further Tor development</a>. We're also looking
en/volunteer.wml  18) for more sponsors &mdash; if you know any companies, NGOs, agencies,
en/volunteer.wml  19) or other organizations that want anonymity / privacy / communications
en/volunteer.wml  20) security, let them know about us.</li>
en/volunteer.wml  21) <li>We're looking for more <a href="<page torusers>">good examples of Tor
en/volunteer.wml  22) users and Tor use cases</a>. If you use Tor for a scenario or purpose not
en/volunteer.wml  23) yet described on that page, and you're comfortable sharing it with us,
en/volunteer.wml  24) we'd love to hear from you.</li>

volunteer.html    25) </ol>
volunteer.html    26) 

en/volunteer.wml  27) <a id="Usability"></a>

en/volunteer.wml  28) <h2><a class="anchor" href="#Usability">Supporting Applications</a></h2>

volunteer.html    29) <ol>

en/volunteer.wml  30) <li>We need more and better ways to intercept DNS requests so they don't "leak" their

en/volunteer.wml  31) request to a local observer while we're trying to be anonymous. (This
en/volunteer.wml  32) happens because the application does the DNS resolve before going to
en/volunteer.wml  33) the SOCKS proxy.)</li>

en/volunteer.wml  34) <li>Tsocks/dsocks items:

en/volunteer.wml  35) <ul>
en/volunteer.wml  36) <li>We need to <a

en/volunteer.wml  37) href="https://wiki.torproject.org/noreply/TheOnionRouter/TSocksPatches">apply

en/volunteer.wml  38) all our tsocks patches</a> and maintain a new fork. We'll host it if
en/volunteer.wml  39) you want.</li>
en/volunteer.wml  40) <li>We should patch Dug Song's "dsocks" program to use Tor's
en/volunteer.wml  41) <i>mapaddress</i> commands from the controller interface, so we
en/volunteer.wml  42) don't waste a whole round-trip inside Tor doing the resolve before
en/volunteer.wml  43) connecting.</li>
en/volunteer.wml  44) <li>We need to make our <i>torify</i> script detect which of tsocks or
en/volunteer.wml  45) dsocks is installed, and call them appropriately. This probably means
en/volunteer.wml  46) unifying their interfaces, and might involve sharing code between them
en/volunteer.wml  47) or discarding one entirely.</li>
en/volunteer.wml  48) </ul>

en/volunteer.wml  49) </li>

en/volunteer.wml  50) <li>People running relays tell us they want to have one BandwidthRate

en/volunteer.wml  51) during some part of the day, and a different BandwidthRate at other
en/volunteer.wml  52) parts of the day. Rather than coding this inside Tor, we should have a
en/volunteer.wml  53) little script that speaks via the <a href="<page gui/index>">Tor
en/volunteer.wml  54) Controller Interface</a>, and does a setconf to change the bandwidth

en/volunteer.wml  55) rate. There is one for Unix and Mac already (it uses bash and cron),

en/volunteer.wml  56) but Windows users still need a solution.

en/volunteer.wml  57) </li>

volunteer.html    58) <li>Speaking of geolocation data, somebody should draw a map of the Earth

en/volunteer.wml  59) with a pin-point for each Tor relay. Bonus points if it updates as the

en/volunteer.wml  60) network grows and changes. Unfortunately, the easy ways to do this involve
en/volunteer.wml  61) sending all the data to Google and having them draw the map for you. How
en/volunteer.wml  62) much does this impact privacy, and do we have any other good options?</li>

volunteer.html    63) </ol>
volunteer.html    64) 

en/volunteer.wml  65) <a id="Documentation"></a>
en/volunteer.wml  66) <h2><a class="anchor" href="#Documentation">Documentation</a></h2>

volunteer.html    67) <ol>

en/volunteer.wml  68) <li>Please help Matt Edman with the documentation and how-tos for his

en/volunteer.wml  69) Tor controller,
en/volunteer.wml  70) <a href="http://vidalia-project.net/">Vidalia</a>.</li>

en/volunteer.wml  71) <li>Evaluate and document

en/volunteer.wml  72) <a href="https://wiki.torproject.org/wiki/TheOnionRouter/TorifyHOWTO">our

en/volunteer.wml  73) list of programs</a> that can be configured to use Tor.</li>

volunteer.html    74) <li>We need better documentation for dynamically intercepting

en/volunteer.wml  75) connections and sending them through Tor. tsocks (Linux), dsocks (BSD),

en/volunteer.wml  76) and freecap (Windows) seem to be good candidates, as would better
en/volunteer.wml  77) use of our new TransPort feature.</li>

en/volunteer.wml  78) <li>We have a huge list of <a href="https://wiki.torproject.org/noreply/TheOnionRouter/SupportPrograms">potentially useful

volunteer.html    79) programs that interface to Tor</a>. Which ones are useful in which
volunteer.html    80) situations? Please help us test them out and document your results.</li>

en/volunteer.wml  81) <li>Help translate the web page and documentation into other
en/volunteer.wml  82) languages. See the <a href="<page translation>">translation

en/volunteer.wml  83) guidelines</a> if you want to help out. We especially need Arabic or
en/volunteer.wml  84) Farsi translations, for the many Tor users in censored areas.</li>

volunteer.html    85) </ol>
volunteer.html    86) 

en/volunteer.wml  87) <a id="Coding"></a>

en/volunteer.wml  88) <a id="Summer"></a>
en/volunteer.wml  89) <a id="Projects"></a>

en/volunteer.wml  90) <h2><a class="anchor" href="#Projects">Good Coding Projects</a></h2>

en/volunteer.wml  91) 
en/volunteer.wml  92) <p>

en/volunteer.wml  93) Here is a list of ideas that are proposed for the <a href="<page gsoc>">Google Summer of Code 2009</a>
en/volunteer.wml  94) Some of the <a href="<svnsandbox>doc/spec/proposals/">current proposals</a> 

en/volunteer.wml  95) might also be short on developers. If you think you can help out, <a href="<page contact>"> let us know!</a> 

en/volunteer.wml  96) </p>
en/volunteer.wml  97) 

en/volunteer.wml  98) <ol>
en/volunteer.wml  99) 

en/volunteer.wml 100) <li>

en/volunteer.wml 101) <b>Tor Node Scanner improvements</b>

en/volunteer.wml 102) <br />

en/volunteer.wml 103) Similar to the SoaT exit scanner (or perhaps even during exit scanning),

en/volunteer.wml 104) statistics can be gathered about the reliability of nodes. Nodes that
en/volunteer.wml 105) fail too high a percentage of their circuits should not be given
en/volunteer.wml 106) Guard status. Perhaps they should have their reported bandwidth
en/volunteer.wml 107) penalized by some ratio as well, or just get marked as Invalid. In
en/volunteer.wml 108) addition, nodes that exhibit a very low average stream capacity but
en/volunteer.wml 109) advertise a very high node bandwidth can also be marked as Invalid.
en/volunteer.wml 110) Much of this statistics gathering is already done, it just needs to be
en/volunteer.wml 111) transformed into something that can be reported to the Directory
en/volunteer.wml 112) Authorities to blacklist/penalize nodes in such a way that clients
en/volunteer.wml 113) will listen.

en/volunteer.wml 114) <br />

en/volunteer.wml 115) In addition, these same statistics can be gathered about the traffic
en/volunteer.wml 116) through a node. Events can be added to the <a

en/volunteer.wml 117) href="https://svn.torproject.org/svn/torctl/trunk/doc/howto.txt">Tor Control

en/volunteer.wml 118) Protocol</a> to
en/volunteer.wml 119) report if a circuit extend attempt through the node succeeds or fails, and
en/volunteer.wml 120) passive statistics can be gathered on both bandwidth and reliability
en/volunteer.wml 121) of other nodes via a node-based monitor using these events. Such a
en/volunteer.wml 122) scanner would also report information on oddly-behaving nodes to
en/volunteer.wml 123) the Directory Authorities, but a communication channel for this
en/volunteer.wml 124) currently does not exist and would need to be developed as well.
en/volunteer.wml 125) </li>
en/volunteer.wml 126) 
en/volunteer.wml 127) <li>
en/volunteer.wml 128) <b>Help track the overall Tor Network status</b>

en/volunteer.wml 129) <br />

en/volunteer.wml 130) It would be great to set up an automated system for tracking network
en/volunteer.wml 131) health over time, graphing it, etc. Part of this project would involve
en/volunteer.wml 132) inventing better metrics for assessing network health and growth. Is the
en/volunteer.wml 133) average uptime of the network increasing? How many relays are qualifying
en/volunteer.wml 134) for Guard status this month compared to last month? What's the turnover
en/volunteer.wml 135) in terms of new relays showing up and relays shutting off? Periodically
en/volunteer.wml 136) people collect brief snapshots, but where it gets really interesting is
en/volunteer.wml 137) when we start tracking data points over time.
en/volunteer.wml 138) <br />
en/volunteer.wml 139) Data could be collected from the "Tor Node Scanner" item above, from
en/volunteer.wml 140) the server descriptors that each relay publishes, and from other
en/volunteer.wml 141) sources. Results over time could be integrated into one of the <a
en/volunteer.wml 142) href="https://torstatus.blutmagie.de/">Tor Status</a> web pages, or be
en/volunteer.wml 143) kept separate. Speaking of the Tor Status pages, take a look at Roger's
en/volunteer.wml 144) <a href="http://archives.seul.org/or/talk/Jan-2008/msg00300.html">Tor
en/volunteer.wml 145) Status wish list</a>.
en/volunteer.wml 146) </li>
en/volunteer.wml 147) 
en/volunteer.wml 148) <li>
en/volunteer.wml 149) <b>Better Debian/Ubuntu Packaging for Tor+Vidalia</b>

en/volunteer.wml 150) <br />
en/volunteer.wml 151) Vidalia currently doesn't play nicely on Debian and Ubuntu with the
en/volunteer.wml 152) default Tor packages. The current Tor packages automatically start Tor
en/volunteer.wml 153) as a daemon running as the debian-tor user and (sensibly) do not have a

en/volunteer.wml 154) <a href="<svnsandbox>doc/spec/control-spec.txt">ControlPort</a> defined
en/volunteer.wml 155) in the default torrc. Consequently, Vidalia will try

en/volunteer.wml 156) to start its own Tor process since it could not connect to the existing

en/volunteer.wml 157) Tor, and Vidalia's Tor process will then exit with an error message

en/volunteer.wml 158) the user likely doesn't understand since Tor cannot bind its listening

en/volunteer.wml 159) ports — they're already in use by the original Tor daemon.

en/volunteer.wml 160) <br />
en/volunteer.wml 161) The current solution involves either telling the user to stop the
en/volunteer.wml 162) existing Tor daemon and let Vidalia start its own Tor process, or
en/volunteer.wml 163) explaining to the user how to set a control port and password in their
en/volunteer.wml 164) torrc. A better solution on Debian would be to use Tor's ControlSocket,
en/volunteer.wml 165) which allows Vidalia to talk to Tor via a Unix domain socket, and could
en/volunteer.wml 166) possibly be enabled by default in Tor's Debian packages. Vidalia can

en/volunteer.wml 167) then authenticate to Tor using filesystem-based (cookie) authentication
en/volunteer.wml 168) if the user running Vidalia is also in the debian-tor group.

en/volunteer.wml 169) <br />
en/volunteer.wml 170) This project will first involve adding support for Tor's ControlSocket
en/volunteer.wml 171) to Vidalia. The student will then develop and test Debian and Ubuntu
en/volunteer.wml 172) packages for Vidalia that conform to Debian's packaging standards and

en/volunteer.wml 173) make sure they work well with the existing Tor packages. We can also

en/volunteer.wml 174) set up an apt repository to host the new Vidalia packages.
en/volunteer.wml 175) <br />

en/volunteer.wml 176) The next challenge would be to find an intuitive usable way for Vidalia
en/volunteer.wml 177) to be able to change Tor's configuration (torrc) even though it is
en/volunteer.wml 178) located in <code>/etc/tor/torrc</code> and thus immutable. The best
en/volunteer.wml 179) idea we've come up with so far is to feed Tor a new configuration via
en/volunteer.wml 180) the ControlSocket when Vidalia starts, but that's bad because Tor starts

en/volunteer.wml 181) each boot with a different configuration than the user wants. The second
en/volunteer.wml 182) best idea

en/volunteer.wml 183) we've come up with is for Vidalia to write out a temporary torrc file
en/volunteer.wml 184) and ask the user to manually move it to <code>/etc/tor/torrc</code>,
en/volunteer.wml 185) but that's bad because users shouldn't have to mess with files directly.
en/volunteer.wml 186) <br />

en/volunteer.wml 187) A person undertaking this project should have prior knowledge of

en/volunteer.wml 188) Debian package management and some C++ development experience. Previous
en/volunteer.wml 189) experience with Qt is helpful, but not required.
en/volunteer.wml 190) </li>
en/volunteer.wml 191) 

en/volunteer.wml 192) <li>
en/volunteer.wml 193) <b>Improving Tor's ability to resist censorship</b>
en/volunteer.wml 194) <br />
en/volunteer.wml 195) The Tor 0.2.0.x series makes <a
en/volunteer.wml 196) href="<svnsandbox>doc/design-paper/blocking.html">significant
en/volunteer.wml 197) improvements</a> in resisting national and organizational censorship.
en/volunteer.wml 198) But Tor still needs better mechanisms for some parts of its
en/volunteer.wml 199) anti-censorship design.  For example, current Tors can only listen on a
en/volunteer.wml 200) single address/port combination at a time.  There's
en/volunteer.wml 201) <a href="<svnsandbox>doc/spec/proposals/118-multiple-orports.txt">a
en/volunteer.wml 202) proposal to address this limitation</a> and allow clients to connect
en/volunteer.wml 203) to any given Tor on multiple addresses and ports, but it needs more
en/volunteer.wml 204) work.  Another anti-censorship project (far more difficult) is to try
en/volunteer.wml 205) to make Tor more scanning-resistant.  Right now, an adversary can identify
en/volunteer.wml 206) <a href="<svnsandbox>doc/spec/proposals/125-bridges.txt">Tor bridges</a>
en/volunteer.wml 207) just by trying to connect to them, following the Tor protocol, and
en/volunteer.wml 208) seeing if they respond.  To solve this, bridges could
en/volunteer.wml 209) <a href="<svnsandbox>doc/design-paper/blocking.html#tth_sEc9.3">act like
en/volunteer.wml 210) webservers</a> (HTTP or HTTPS) when contacted by port-scanning tools,
en/volunteer.wml 211) and not act like bridges until the user provides a bridge-specific key.
en/volunteer.wml 212) <br />
en/volunteer.wml 213) This project involves a lot of research and design. One of the big
en/volunteer.wml 214) challenges will be identifying and crafting approaches that can still
en/volunteer.wml 215) resist an adversary even after the adversary knows the design, and
en/volunteer.wml 216) then trading off censorship resistance with usability and robustness.
en/volunteer.wml 217) </li>
en/volunteer.wml 218) 
en/volunteer.wml 219) <li>
en/volunteer.wml 220) <b>Tor/Polipo/Vidalia Auto-Update Framework</b>
en/volunteer.wml 221) <br />
en/volunteer.wml 222) We're in need of a good authenticated-update framework.
en/volunteer.wml 223) Vidalia already has the ability to notice when the user is running an
en/volunteer.wml 224) outdated or unrecommended version of Tor, using signed statements inside
en/volunteer.wml 225) the Tor directory information. Currently, Vidalia simply pops
en/volunteer.wml 226) up a little message box that lets the user know they should manually
en/volunteer.wml 227) upgrade. The goal of this project would be to extend Vidalia with the
en/volunteer.wml 228) ability to also fetch and install the updated Tor software for the
en/volunteer.wml 229) user. We should do the fetches via Tor when possible, but also fall back
en/volunteer.wml 230) to direct fetches in a smart way. Time permitting, we would also like
en/volunteer.wml 231) to be able to update other
en/volunteer.wml 232) applications included in the bundled installers, such as Polipo and
en/volunteer.wml 233) Vidalia itself.
en/volunteer.wml 234) <br />
en/volunteer.wml 235) To complete this project, the student will first need to first investigate
en/volunteer.wml 236) the existing auto-update frameworks (e.g., Sparkle on OS X) to evaluate
en/volunteer.wml 237) their strengths, weaknesses, security properties, and ability to be
en/volunteer.wml 238) integrated into Vidalia. If none are found to be suitable, the student
en/volunteer.wml 239) will design their own auto-update framework, document the design, and
en/volunteer.wml 240) then discuss the design with other developers to assess any security
en/volunteer.wml 241) issues. The student will then implement their framework (or integrate
en/volunteer.wml 242) an existing one) and test it.
en/volunteer.wml 243) <br />

en/volunteer.wml 244) A person undertaking this project should have good C++ development
en/volunteer.wml 245) experience. Previous experience with Qt is helpful, but not required. One
en/volunteer.wml 246) should also have a good understanding of common security

en/volunteer.wml 247) practices, such as package signature verification. Good writing ability
en/volunteer.wml 248) is also important for this project, since a vital step of the project

en/volunteer.wml 249) will be producing a design document to review and discuss
en/volunteer.wml 250) with others prior to implementation.

en/volunteer.wml 251) </li>
en/volunteer.wml 252) 
en/volunteer.wml 253) <li>
en/volunteer.wml 254) <b>An Improved and More Usable Network Map in Vidalia</b>
en/volunteer.wml 255) <br />
en/volunteer.wml 256) One of Vidalia's existing features is a network map that shows the user
en/volunteer.wml 257) the approximate geographic location of relays in the Tor network and
en/volunteer.wml 258) plots the paths the user's traffic takes as it is tunneled through the
en/volunteer.wml 259) Tor network. The map is currently not very interactive and has rather
en/volunteer.wml 260) poor graphics. Instead, we would like to leverage KDE's Marble widget
en/volunteer.wml 261) that gives us a better quality map and enables improved interactivity,
en/volunteer.wml 262) such as allowing the user to click on individual relays or circuits to
en/volunteer.wml 263) display additional information. We might also consider adding the ability
en/volunteer.wml 264) for users to click on a particular relay or a country containing one or
en/volunteer.wml 265) more Tor exit relays and say, "I want my connections to foo.com to exit
en/volunteer.wml 266) from here."
en/volunteer.wml 267) <br />

en/volunteer.wml 268) This project will first involve getting familiar with Vidalia
en/volunteer.wml 269) and the Marble widget's API. One will then integrate the widget

en/volunteer.wml 270) into Vidalia and customize Marble to be better suited for our application,
en/volunteer.wml 271) such as making circuits clickable, storing cached map data in Vidalia's
en/volunteer.wml 272) own data directory, and customizing some of the widget's dialogs.
en/volunteer.wml 273) <br />

en/volunteer.wml 274) A person undertaking this project should have good C++ development

en/volunteer.wml 275) experience. Previous experience with Qt and CMake is helpful, but not
en/volunteer.wml 276) required.
en/volunteer.wml 277) </li>
en/volunteer.wml 278) 

en/volunteer.wml 279) <li>

en/volunteer.wml 280) <b>Tor Controller Status Event Interface</b>

en/volunteer.wml 281) <br />

en/volunteer.wml 282) There are a number of status changes inside Tor of which the user may need

en/volunteer.wml 283) to be informed. For example, if the user is trying to set up his Tor as a
en/volunteer.wml 284) relay and Tor decides that its ports are not reachable from outside

en/volunteer.wml 285) the user's network, we should alert the user. Currently, all the user

en/volunteer.wml 286) gets is a couple log messages in Vidalia's 'message log' window, which they

en/volunteer.wml 287) likely never see since they don't receive a notification that something
en/volunteer.wml 288) has gone wrong. Even if the user does actually look at the message log,
en/volunteer.wml 289) most of the messages make little sense to the novice user.
en/volunteer.wml 290) <br />
en/volunteer.wml 291) Tor has the ability to inform Vidalia of many such status changes, and
en/volunteer.wml 292) we recently implemented support for a couple of these events. Still,
en/volunteer.wml 293) there are many more status events the user should be informed of and we
en/volunteer.wml 294) need a better UI for actually displaying them to the user.
en/volunteer.wml 295) <br />
en/volunteer.wml 296) The goal of this project then is to design and implement a UI for
en/volunteer.wml 297) displaying Tor status events to the user. For example, we might put a
en/volunteer.wml 298) little badge on Vidalia's tray icon that alerts the user to new status
en/volunteer.wml 299) events they should look at. Double-clicking the icon could bring up a
en/volunteer.wml 300) dialog that summarizes recent status events in simple terms and maybe

en/volunteer.wml 301) suggests a remedy for any negative events if they can be corrected by

en/volunteer.wml 302) the user. Of course, this is just an example and one is free to

en/volunteer.wml 303) suggest another approach.
en/volunteer.wml 304) <br />

en/volunteer.wml 305) A person undertaking this project should have good UI design and layout

en/volunteer.wml 306) and some C++ development experience. Previous experience with Qt and

en/volunteer.wml 307) Qt's Designer will be very helpful, but are not required. Some

en/volunteer.wml 308) English writing ability will also be useful, since this project will
en/volunteer.wml 309) likely involve writing small amounts of help documentation that should
en/volunteer.wml 310) be understandable by non-technical users. Bonus points for some graphic
en/volunteer.wml 311) design/Photoshop fu, since we might want/need some shiny new icons too.
en/volunteer.wml 312) </li>
en/volunteer.wml 313) 

en/volunteer.wml 314) <li>

en/volunteer.wml 315) <b>Improvements on our active browser configuration tester</b> -

en/volunteer.wml 316) <a href="https://check.torproject.org/">https://check.torproject.org/</a>

en/volunteer.wml 317) <br />
en/volunteer.wml 318) We currently have a functional web page to detect if Tor is working. It

en/volunteer.wml 319) has a few places where it falls short. It requires improvements with

en/volunteer.wml 320) regard to default languages and functionality. It currently only responds
en/volunteer.wml 321) in English. In addition, it is a hack of a perl script that should have
en/volunteer.wml 322) never seen the light of day. It should probably be rewritten in python

en/volunteer.wml 323) with multi-lingual support in mind. It currently uses the <a
en/volunteer.wml 324) href="http://exitlist.torproject.org/">Tor DNS exit list</a>
en/volunteer.wml 325) and should continue to do so in the future. It currently result in certain

en/volunteer.wml 326) false positives and these should be discovered, documented, and fixed
en/volunteer.wml 327) where possible. Anyone working on this project should be interested in

en/volunteer.wml 328) DNS, basic perl or preferably python programming skills, and will have

en/volunteer.wml 329) to interact minimally with Tor to test their code.

en/volunteer.wml 330) <br />
en/volunteer.wml 331) If you want to make the project more exciting
en/volunteer.wml 332) and involve more design and coding, take a look at <a
en/volunteer.wml 333) href="<svnsandbox>doc/spec/proposals/131-verify-tor-usage.txt">proposal
en/volunteer.wml 334) 131-verify-tor-usage.txt</a>.

en/volunteer.wml 335) </li>
en/volunteer.wml 336) 
en/volunteer.wml 337) <li>

en/volunteer.wml 338) <b>Improvements on our DNS Exit List service</b> -

en/volunteer.wml 339) <a href="http://exitlist.torproject.org/">http://exitlist.torproject.org/</a>

en/volunteer.wml 340) <br />

en/volunteer.wml 341) The <a href="http://p56soo2ibjkx23xo.onion/">exitlist software</a>
en/volunteer.wml 342) is written by our fabulous anonymous

en/volunteer.wml 343) contributer Tup. It's a DNS server written in Haskell that supports part of our <a

en/volunteer.wml 344) href="<svnsandbox>doc/contrib/torel-design.txt">exitlist

en/volunteer.wml 345) design document</a>. Currently, it is functional and it is used by

en/volunteer.wml 346) check.torproject.org and other users. The issues that are outstanding
en/volunteer.wml 347) are mostly aesthetic. This wonderful service could use a much better
en/volunteer.wml 348) website using the common Tor theme. It would be best served with better
en/volunteer.wml 349) documentation for common services that use an RBL. It could use more
en/volunteer.wml 350) publicity. A person working on this project should be interested in DNS,
en/volunteer.wml 351) basic RBL configuration for popular services, and writing documentation.
en/volunteer.wml 352) The person would require minimal Tor interaction — testing their
en/volunteer.wml 353) own documentation at the very least. Furthermore, it would be useful

en/volunteer.wml 354) if they were interested in Haskell and wanted to implement more of the

en/volunteer.wml 355) torel-design.txt suggestions.
en/volunteer.wml 356) </li>
en/volunteer.wml 357) 
en/volunteer.wml 358) <li>

en/volunteer.wml 359) <b>Testing integration of Tor with web browsers for our end users</b>

en/volunteer.wml 360) <br />

en/volunteer.wml 361) The Tor project currently lacks a solid test suite to ensure that a
en/volunteer.wml 362) user has a properly and safely configured web browser. It should test for as

en/volunteer.wml 363) many known issues as possible. It should attempt to decloak the

en/volunteer.wml 364) user in any way possible. Two current webpages that track these

en/volunteer.wml 365) kinds of issues are run by Greg Fleischer and HD Moore. Greg keeps a nice <a

en/volunteer.wml 366) href="http://pseudo-flaw.net/tor/torbutton/">list of issues along
en/volunteer.wml 367) with their proof of concept code, bug issues, etc</a>. HD Moore runs

en/volunteer.wml 368) the <a href="http://www.decloak.net/">metasploit

en/volunteer.wml 369) decloak website</a>. A person interested in defending Tor could start

en/volunteer.wml 370) by collecting as many workable and known methods for decloaking a

en/volunteer.wml 371) Tor user. (<a href="https://torcheck.xenobite.eu/">This page</a> may

en/volunteer.wml 372) be helpful as a start.) One should be familiar with the common pitfalls but

en/volunteer.wml 373) possibly have new methods in mind for implementing decloaking issues. The
en/volunteer.wml 374) website should ensure that it tells a user what their problem is. It
en/volunteer.wml 375) should help them to fix the problem or direct them to the proper support

en/volunteer.wml 376) channels. The person should also be closely familiar with using Tor and how

en/volunteer.wml 377) to prevent Tor information leakage.

en/volunteer.wml 378) </li>
en/volunteer.wml 379) 

en/volunteer.wml 380) <li>

en/volunteer.wml 381) <b>Libevent and Tor integration improvements</b>
en/volunteer.wml 382) <br />

en/volunteer.wml 383) Tor should make better use of the more recent features of Niels
en/volunteer.wml 384) Provos's <a href="http://monkey.org/~provos/libevent/">Libevent</a>

en/volunteer.wml 385) library.  Tor already uses Libevent for its low-level asynchronous IO

en/volunteer.wml 386) calls, and could also use Libevent's increasingly good implementations

en/volunteer.wml 387) of network buffers and of HTTP.  This wouldn't be simply a matter of

en/volunteer.wml 388) replacing Tor's internal calls with calls to Libevent: instead, we'll

en/volunteer.wml 389) need to refactor Tor to use Libevent calls that do not follow the

en/volunteer.wml 390) same models as Tor's existing backends. Also, we'll need to add
en/volunteer.wml 391) missing functionality to Libevent as needed — most difficult likely
en/volunteer.wml 392) will be adding OpenSSL support on top of Libevent's buffer abstraction.
en/volunteer.wml 393) Also tricky will be adding rate-limiting to Libevent.

en/volunteer.wml 394) </li>
en/volunteer.wml 395) 
en/volunteer.wml 396) <li>

en/volunteer.wml 397) <b>Tuneup Tor!</b>
en/volunteer.wml 398) <br />

en/volunteer.wml 399) Right now, Tor relays measure and report their own bandwidth, and Tor
en/volunteer.wml 400) clients choose which relays to use in part based on that bandwidth.
en/volunteer.wml 401) This approach is vulnerable to
en/volunteer.wml 402) <a href="http://freehaven.net/anonbib/#bauer:wpes2007">attacks where
en/volunteer.wml 403) relays lie about their bandwidth</a>;
en/volunteer.wml 404) to address this, Tor currently caps the maximum bandwidth
en/volunteer.wml 405) it's willing to believe any relay provides.  This is a limited fix, and
en/volunteer.wml 406) a waste of bandwidth capacity to boot.  Instead,

en/volunteer.wml 407) Tor should possibly measure bandwidth in a more distributed way, perhaps
en/volunteer.wml 408) as described in the

en/volunteer.wml 409) <a href="http://freehaven.net/anonbib/author.html#snader08">"A Tune-up for
en/volunteer.wml 410) Tor"</a> paper

en/volunteer.wml 411) by Snader and Borisov. One could use current testing code to

en/volunteer.wml 412) double-check this paper's findings and verify the extent to which they

en/volunteer.wml 413) dovetail with Tor as deployed in the wild, and determine good ways to
en/volunteer.wml 414) incorporate them into their suggestions Tor network without adding too

en/volunteer.wml 415) much communications overhead between relays and directory

en/volunteer.wml 416) authorities.

en/volunteer.wml 417) </li>
en/volunteer.wml 418) 

en/volunteer.wml 419) <!--

en/volunteer.wml 420) <li>

en/volunteer.wml 421) <b>Improving the Tor QA process: Continuous Integration for Windows builds</b>
en/volunteer.wml 422) <br />

en/volunteer.wml 423) It would be useful to have automated build processes for Windows and
en/volunteer.wml 424) probably other platforms. The purpose of having a continuous integration
en/volunteer.wml 425) build environment is to ensure that Windows isn't left behind for any of
en/volunteer.wml 426) the software projects used in the Tor project or its accompanying.<br />
en/volunteer.wml 427) Buildbot may be a good choice for this as it appears to support all of

en/volunteer.wml 428) the platforms Tor does. See the

en/volunteer.wml 429) <a href="http://en.wikipedia.org/wiki/BuildBot">wikipedia entry for

en/volunteer.wml 430) buildbot</a>.<br />
en/volunteer.wml 431) There may be better options and the person undertaking this task should
en/volunteer.wml 432) evaluate other options. Any person working on this automatic build
en/volunteer.wml 433) process should have experience or be willing to learn how to build all
en/volunteer.wml 434) of the respective Tor related code bases from scratch. Furthermore, the
en/volunteer.wml 435) person should have some experience building software in Windows
en/volunteer.wml 436) environments as this is the target audience we want to ensure we do not
en/volunteer.wml 437) leave behind. It would require close work with the Tor source code but

en/volunteer.wml 438) probably only in the form of building, not authoring.<br />
en/volunteer.wml 439) Additionally, we need to automate our performance testing for all platforms.

en/volunteer.wml 440) We've got buildbot (except on Windows — as noted above) to automate

en/volunteer.wml 441) our regular integration and compile testing already,
en/volunteer.wml 442) but we need to get our network simulation tests (as built in torflow)
en/volunteer.wml 443) updated for more recent versions of Tor, and designed to launch a test
en/volunteer.wml 444) network either on a single machine, or across several, so we can test

en/volunteer.wml 445) changes in performance on machines in different roles automatically.

en/volunteer.wml 446) </li>

en/volunteer.wml 447) -->

en/volunteer.wml 448) 

en/volunteer.wml 449) <li>

en/volunteer.wml 450) <b>Improve our unit testing process</b>
en/volunteer.wml 451) <br />

en/volunteer.wml 452) Tor needs to be far more tested. This is a multi-part effort. To start

en/volunteer.wml 453) with, our unit test coverage should rise substantially, especially in

en/volunteer.wml 454) the areas outside the utility functions. This will require significant

en/volunteer.wml 455) refactoring of some parts of Tor, in order to dissociate as much logic

en/volunteer.wml 456) as possible from globals.
en/volunteer.wml 457) <br />

en/volunteer.wml 458) Additionally, we need to automate our performance testing. We've got

en/volunteer.wml 459) buildbot to automate our regular integration and compile testing already
en/volunteer.wml 460) (though we need somebody to set it up on Windows),
en/volunteer.wml 461) but we need to get our network simulation tests (as built in TorFlow: see
en/volunteer.wml 462) the "Tor Node Scanner improvements" item)

en/volunteer.wml 463) updated for more recent versions of Tor, and designed to launch a test
en/volunteer.wml 464) network either on a single machine, or across several, so we can test

en/volunteer.wml 465) changes in performance on machines in different roles automatically.

en/volunteer.wml 466) </li>
en/volunteer.wml 467) 

en/volunteer.wml 468) <li>

en/volunteer.wml 469) <b>Help revive an independent Tor client implementation</b>

en/volunteer.wml 470) <br />

en/volunteer.wml 471) Reanimate one of the approaches to implement a Tor client in Java,
en/volunteer.wml 472) e.g. the <a href="http://onioncoffee.sourceforge.net/">OnionCoffee
en/volunteer.wml 473) project</a>, and make it run on <a
en/volunteer.wml 474) href="http://code.google.com/android/">Android</a>. The first step
en/volunteer.wml 475) would be to port the existing code and execute it in an Android
en/volunteer.wml 476) environment. Next, the code should be updated to support the newer Tor
en/volunteer.wml 477) protocol versions like the <a href="<svnsandbox>doc/spec/dir-spec.txt">v3
en/volunteer.wml 478) directory protocol</a>. Further, support for requesting or even

en/volunteer.wml 479) providing Tor hidden services would be neat, but not required.
en/volunteer.wml 480) <br />

en/volunteer.wml 481) A prospective developer should be able to understand and write new Java
en/volunteer.wml 482) code, including

en/volunteer.wml 483) a Java cryptography API. Being able to read C code would be helpful,

en/volunteer.wml 484) too. One should be willing to read the existing documentation,

en/volunteer.wml 485) implement code based on it, and refine the documentation
en/volunteer.wml 486) when things are underdocumented. This project is mostly about coding and

en/volunteer.wml 487) to a small degree about design.
en/volunteer.wml 488) </li>
en/volunteer.wml 489) 
en/volunteer.wml 490) <li>

en/volunteer.wml 491) <b>Bring moniTor to life</b>
en/volunteer.wml 492) <br />

en/volunteer.wml 493) Implement a <a href="http://www.ss64.com/bash/top.html">top-like</a>
en/volunteer.wml 494) management tool for Tor relays. The purpose of such a tool would be
en/volunteer.wml 495) to monitor a local Tor relay via its control port and include useful
en/volunteer.wml 496) system information of the underlying machine. When running this tool, it
en/volunteer.wml 497) would dynamically update its content like top does for Linux processes.
en/volunteer.wml 498) <a href="http://archives.seul.org/or/dev/Jan-2008/msg00005.html">This

en/volunteer.wml 499) or-dev post</a> might be a good first read.
en/volunteer.wml 500) <br />

en/volunteer.wml 501) A person interested in this should be familiar

en/volunteer.wml 502) with or willing to learn about administering a Tor relay and configuring
en/volunteer.wml 503) it via its control port. As an initial prototype is written in Python,
en/volunteer.wml 504) some knowledge about writing Python code would be helpful, too. This

en/volunteer.wml 505) project is one part about identifying requirements to such a
en/volunteer.wml 506) tool and designing its interface, and one part lots of coding.

en/volunteer.wml 507) </li>
en/volunteer.wml 508) 

en/volunteer.wml 509) <li>
en/volunteer.wml 510) <b>Torbutton improvements</b>
en/volunteer.wml 511) <br />
en/volunteer.wml 512) Torbutton has a number of improvements that can be made in the post-1.2
en/volunteer.wml 513) timeframe. Most of these are documented as feature requests in the <a

en/volunteer.wml 514) href="https://bugs.torproject.org/flyspray/index.php?tasks=all&project=5">Torbutton

en/volunteer.wml 515) flyspray section</a>. Good examples include: stripping off node.exit on http
en/volunteer.wml 516) headers, more fine-grained control over formfill blocking, improved referrer

en/volunteer.wml 517) spoofing based on the domain of the site (a-la <a

en/volunteer.wml 518) href="https://addons.mozilla.org/en-US/firefox/addon/953">refcontrol extension</a>),

en/volunteer.wml 519) tighter integration with Vidalia for reporting Tor status, a New Identity
en/volunteer.wml 520) button with Tor integration and multiple identity management, and anything

en/volunteer.wml 521) else you might think of.

en/volunteer.wml 522) <br />
en/volunteer.wml 523) This work would be independent coding in Javascript and the fun world of <a
en/volunteer.wml 524) href="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">XUL</a>,
en/volunteer.wml 525) with not too much involvement in the Tor internals.

en/volunteer.wml 526) </li>
en/volunteer.wml 527) 

en/volunteer.wml 528) <li>

en/volunteer.wml 529) <b>Porting Polipo to Windows</b>
en/volunteer.wml 530) <br />

en/volunteer.wml 531) Help port <a
en/volunteer.wml 532) href="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</a> to

en/volunteer.wml 533) Windows. Example topics to tackle include:
en/volunteer.wml 534) 1) handle spaces in path names and understand the filesystem
en/volunteer.wml 535) namespace — that is, where application data, personal data,

en/volunteer.wml 536) and program data typically reside in various versions of Windows. 2) the
en/volunteer.wml 537) ability to handle ipv6 communications. 3) the ability to asynchronously
en/volunteer.wml 538) query name servers, find the system nameservers, and manage netbios
en/volunteer.wml 539) and dns queries. 4) use native regex capabilities of Windows, rather
en/volunteer.wml 540) than using 3rd party GNU regex libraries. 5) manage events and buffers
en/volunteer.wml 541) natively (i.e. in Unix-like OSes, Polipo defaults to 25% of ram, in
en/volunteer.wml 542) Windows it's whatever the config specifies). 6) some sort of GUI config
en/volunteer.wml 543) and reporting tool, bonus if it has a systray icon with right clickable
en/volunteer.wml 544) menu options. Double bonus if it's cross-platform compatible.
en/volunteer.wml 545) </li>
en/volunteer.wml 546) 
en/volunteer.wml 547) <li>

en/volunteer.wml 548) <b>Make our diagrams beautiful and automated</b>

en/volunteer.wml 549) <br />

en/volunteer.wml 550) We need a way to generate the website diagrams (for example, the "How
en/volunteer.wml 551) Tor Works" pictures on the <a href="<page overview>">overview page</a>
en/volunteer.wml 552) from source, so we can translate them as UTF-8 text rather than edit
en/volunteer.wml 553) them by hand with Gimp. We might want to
en/volunteer.wml 554) integrate this as an wml file so translations are easy and images are

en/volunteer.wml 555) generated in multiple languages whenever we build the website. 

en/volunteer.wml 556) </li>
en/volunteer.wml 557) 

en/volunteer.wml 558) <li>
en/volunteer.wml 559) <b>Improve the LiveCD offerings for the Tor community</b>
en/volunteer.wml 560) <br />
en/volunteer.wml 561) How can we make the <a

en/volunteer.wml 562) href="http://anonymityanywhere.com/incognito/">Incognito LiveCD</a>

en/volunteer.wml 563) easier to maintain, improve, and document?
en/volunteer.wml 564) </li>

en/volunteer.wml 565) 

en/volunteer.wml 566) <li>
en/volunteer.wml 567) <b>Rework and extend Blossom</b>
en/volunteer.wml 568) <br />
en/volunteer.wml 569) Rework and extend Blossom (a tool for monitoring and
en/volunteer.wml 570) selecting appropriate Tor circuits based upon exit node requirements
en/volunteer.wml 571) specified by the user) to gather data in a self-contained way, with
en/volunteer.wml 572) parameters easily configurable by the user.  Blossom is presently
en/volunteer.wml 573) implemented as a single Python script that interfaces with Tor using the
en/volunteer.wml 574) Controller interface and depends upon metadata about Tor nodes obtained
en/volunteer.wml 575) via external processes, such as a webpage indicating status of the nodes
en/volunteer.wml 576) plus publically available data from DNS, whois, etc.  This project has
en/volunteer.wml 577) two parts: (1) Determine which additional metadata may be useful and
en/volunteer.wml 578) rework Blossom so that it cleanly obtains the metadata on its own rather
en/volunteer.wml 579) than depend upon external scripts (this may, for example, involve
en/volunteer.wml 580) additional threads or inter-process communication), and (2) develop a
en/volunteer.wml 581) means by which the user can easily configure Blossom, starting with a
en/volunteer.wml 582) configuration file and possibly working up to a web configuration engine.

en/volunteer.wml 583) Knowledge of Tor and Python are important; knowledge of
en/volunteer.wml 584) TCP, interprocess communication, and Perl will also be helpful.  An
en/volunteer.wml 585) interest in network neutrality is important as well, since the
en/volunteer.wml 586) principles of evaluating and understanding internet inconsistency are at
en/volunteer.wml 587) the core of the Blossom effort.

en/volunteer.wml 588) </li>
en/volunteer.wml 589) 
en/volunteer.wml 590) <li>
en/volunteer.wml 591) <b>Improve Blossom: Allow users to qualitatively describe exit nodes they desire</b>
en/volunteer.wml 592) <br />
en/volunteer.wml 593) Develop and implement a means of affording Blossom
en/volunteer.wml 594) users the ability to qualitatively describe the exit node that they
en/volunteer.wml 595) want.  The Internet is an inconsistent place: some Tor exit nodes see
en/volunteer.wml 596) the world differently than others.  As presently implemented, Blossom (a
en/volunteer.wml 597) tool for monitoring and selecting appropriate Tor circuits based upon
en/volunteer.wml 598) exit node requirements specified by the user) lacks a sufficiently rich
en/volunteer.wml 599) language to describe how the different vantage points are different.
en/volunteer.wml 600) For example, some exit nodes may have an upstream network that filters
en/volunteer.wml 601) certain kinds of traffic or certain websites.  Other exit nodes may
en/volunteer.wml 602) provide access to special content as a result of their location, perhaps
en/volunteer.wml 603) as a result of discrimination on the part of the content providers
en/volunteer.wml 604) themselves.  This project has two parts: (1) develop a language for
en/volunteer.wml 605) describing characteristics of networks in which exit nodes reside, and
en/volunteer.wml 606) (2) incorporate this language into Blossom so that users can select Tor
en/volunteer.wml 607) paths based upon the description.

en/volunteer.wml 608) Knowledge of Tor and Python are important; knowledge of
en/volunteer.wml 609) TCP, interprocess communication, and Perl will also be helpful.  An
en/volunteer.wml 610) interest in network neutrality is important as well, since the
en/volunteer.wml 611) principles of evaluating and understanding internet inconsistency are at
en/volunteer.wml 612) the core of the Blossom effort.

en/volunteer.wml 613) </li>
en/volunteer.wml 614) 

en/volunteer.wml 615) <li>
en/volunteer.wml 616) <b>Bring up new ideas!</b>
en/volunteer.wml 617) <br />
en/volunteer.wml 618) Don't like any of these? Look at the <a

en/volunteer.wml 619) href="<svnsandbox>doc/roadmaps/2008-12-19-roadmap-full.pdf">Tor development

en/volunteer.wml 620) roadmap</a> for more ideas.
en/volunteer.wml 621) </li>
en/volunteer.wml 622) 

en/volunteer.wml 623) </ol>
en/volunteer.wml 624) 

en/volunteer.wml 625) <a id="OtherCoding"></a>
en/volunteer.wml 626) <h2><a class="anchor" href="#OtherCoding">Other Coding and Design related ideas</a></h2>

volunteer.html   627) <ol>

en/volunteer.wml 628) <li>Tor relays don't work well on Windows XP. On

en/volunteer.wml 629) Windows, Tor uses the standard <tt>select()</tt> system

en/volunteer.wml 630) call, which uses space in the non-page pool. This means

en/volunteer.wml 631) that a medium sized Tor relay will empty the non-page pool, <a

en/volunteer.wml 632) href="https://wiki.torproject.org/noreply/TheOnionRouter/WindowsBufferProblems">causing

en/volunteer.wml 633) havoc and system crashes</a>. We should probably be using overlapped IO

en/volunteer.wml 634) instead. One solution would be to teach <a
en/volunteer.wml 635) href="http://www.monkey.org/~provos/libevent/">libevent</a> how to use
en/volunteer.wml 636) overlapped IO rather than select() on Windows, and then adapt Tor to

en/volunteer.wml 637) the new libevent interface. Christian King made a

en/volunteer.wml 638) <a href="https://svn.torproject.org/svn/libevent-urz/trunk/">good

en/volunteer.wml 639) start</a> on this in the summer of 2007.</li>

en/volunteer.wml 640) 

en/volunteer.wml 641) <li>We need to actually start building our <a href="<page
en/volunteer.wml 642) documentation>#DesignDoc">blocking-resistance design</a>. This involves

en/volunteer.wml 643) fleshing out the design, modifying many different pieces of Tor, adapting
en/volunteer.wml 644) <a href="http://vidalia-project.net/">Vidalia</a> so it supports the
en/volunteer.wml 645) new features, and planning for deployment.</li>

en/volunteer.wml 646) 

en/volunteer.wml 647) <li>We need a flexible simulator framework for studying end-to-end
en/volunteer.wml 648) traffic confirmation attacks. Many researchers have whipped up ad hoc
en/volunteer.wml 649) simulators to support their intuition either that the attacks work
en/volunteer.wml 650) really well or that some defense works great. Can we build a simulator
en/volunteer.wml 651) that's clearly documented and open enough that everybody knows it's
en/volunteer.wml 652) giving a reasonable answer? This will spur a lot of new research.
en/volunteer.wml 653) See the entry <a href="#Research">below</a> on confirmation attacks for
en/volunteer.wml 654) details on the research side of this task &mdash; who knows, when it's
en/volunteer.wml 655) done maybe you can help write a paper or three also.</li>

en/volunteer.wml 656) 

en/volunteer.wml 657) <li>Tor 0.1.1.x and later include support for hardware crypto accelerators

en/volunteer.wml 658) via OpenSSL. Nobody has ever tested it, though. Does somebody want to get

volunteer.html   659) a card and let us know how it goes?</li>

en/volunteer.wml 660) 

volunteer.html   661) <li>Perform a security analysis of Tor with <a
volunteer.html   662) href="http://en.wikipedia.org/wiki/Fuzz_testing">"fuzz"</a>. Determine

en/volunteer.wml 663) if there are good fuzzing libraries out there for what we want. Win fame by

volunteer.html   664) getting credit when we put out a new release because of you!</li>

en/volunteer.wml 665) 

volunteer.html   666) <li>Tor uses TCP for transport and TLS for link
volunteer.html   667) encryption. This is nice and simple, but it means all cells
volunteer.html   668) on a link are delayed when a single packet gets dropped, and
volunteer.html   669) it means we can only reasonably support TCP streams. We have a <a

en/volunteer.wml 670) href="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#TransportIPnotTCP">list

en/volunteer.wml 671) of reasons why we haven't shifted to UDP transport</a>, but it would
en/volunteer.wml 672) be great to see that list get shorter. We also have a proposed <a

en/volunteer.wml 673) href="<svnsandbox>doc/spec/proposals/100-tor-spec-udp.txt">specification
en/volunteer.wml 674) for Tor and

en/volunteer.wml 675) UDP</a> &mdash; please let us know what's wrong with it.</li>

en/volunteer.wml 676) 

volunteer.html   677) <li>We're not that far from having IPv6 support for destination addresses
volunteer.html   678) (at exit nodes). If you care strongly about IPv6, that's probably the
volunteer.html   679) first place to start.</li>

volunteer.html   680) </ol>
volunteer.html   681) 

en/volunteer.wml 682) <a id="Research"></a>
en/volunteer.wml 683) <h2><a class="anchor" href="#Research">Research</a></h2>

volunteer.html   684) <ol>

volunteer.html   685) <li>The "website fingerprinting attack": make a list of a few
volunteer.html   686) hundred popular websites, download their pages, and make a set of
volunteer.html   687) "signatures" for each site. Then observe a Tor client's traffic. As
volunteer.html   688) you watch him receive data, you quickly approach a guess about which
volunteer.html   689) (if any) of those sites he is visiting. First, how effective is
volunteer.html   690) this attack on the deployed Tor codebase? Then start exploring
volunteer.html   691) defenses: for example, we could change Tor's cell size from 512
volunteer.html   692) bytes to 1024 bytes, we could employ padding techniques like <a
volunteer.html   693) href="http://freehaven.net/anonbib/#timing-fc2004">defensive dropping</a>,
volunteer.html   694) or we could add traffic delays. How much of an impact do these have,
volunteer.html   695) and how much usability impact (using some suitable metric) is there from
volunteer.html   696) a successful defense in each case?</li>

volunteer.html   697) <li>The "end-to-end traffic confirmation attack":
volunteer.html   698) by watching traffic at Alice and at Bob, we can <a
volunteer.html   699) href="http://freehaven.net/anonbib/#danezis:pet2004">compare
volunteer.html   700) traffic signatures and become convinced that we're watching the same
volunteer.html   701) stream</a>. So far Tor accepts this as a fact of life and assumes this
volunteer.html   702) attack is trivial in all cases. First of all, is that actually true? How
volunteer.html   703) much traffic of what sort of distribution is needed before the adversary
volunteer.html   704) is confident he has won? Are there scenarios (e.g. not transmitting much)
volunteer.html   705) that slow down the attack? Do some traffic padding or traffic shaping
volunteer.html   706) schemes work better than others?</li>

en/volunteer.wml 707) <li>A related question is: Does running a relay/bridge provide additional
en/volunteer.wml 708) protection against these timing attacks? Can an external adversary that can't

en/volunteer.wml 709) see inside TLS links still recognize individual streams reliably?

en/volunteer.wml 710) Does the amount of traffic carried degrade this ability any? What if the
en/volunteer.wml 711) client-relay deliberately delayed upstream relayed traffic to create a queue
en/volunteer.wml 712) that could be used to mimic timings of client downstream traffic to make it
en/volunteer.wml 713) look like it was also relayed? This same queue could also be used for masking
en/volunteer.wml 714) timings in client upstream traffic with the techniques from <a
en/volunteer.wml 715) href="http://www.freehaven.net/anonbib/#ShWa-Timing06">adaptive padding</a>,
en/volunteer.wml 716) but without the need for additional traffic. Would such an interleaving of
en/volunteer.wml 717) client upstream traffic obscure timings for external adversaries? Would the
en/volunteer.wml 718) strategies need to be adjusted for asymmetric links? For example, on
en/volunteer.wml 719) asymmetric links, is it actually possible to differentiate client traffic from
en/volunteer.wml 720) natural bursts due to their asymmetric capacity? Or is it easier than
en/volunteer.wml 721) symmetric links for some other reason?</li>

en/volunteer.wml 722) <li>Repeat Murdoch and Danezis's <a
en/volunteer.wml 723) href="http://www.cl.cam.ac.uk/~sjm217/projects/anon/#torta">attack from
en/volunteer.wml 724) Oakland 05</a> on the current Tor network. See if you can learn why it
en/volunteer.wml 725) works well on some nodes and not well on others. (My theory is that the
en/volunteer.wml 726) fast nodes with spare capacity resist the attack better.) If that's true,
en/volunteer.wml 727) then experiment with the RelayBandwidthRate and RelayBandwidthBurst
en/volunteer.wml 728) options to run a relay that is used as a client while relaying the
en/volunteer.wml 729) attacker's traffic: as we crank down the RelayBandwidthRate, does the
en/volunteer.wml 730) attack get harder? What's the right ratio of RelayBandwidthRate to
en/volunteer.wml 731) actually capacity? Or is it a ratio at all? While we're at it, does a
en/volunteer.wml 732) much larger set of candidate relays increase the false positive rate
en/volunteer.wml 733) or other complexity for the attack? (The Tor network is now almost two
en/volunteer.wml 734) orders of magnitude larger than it was when they wrote their paper.) Be
en/volunteer.wml 735) sure to read <a href="http://freehaven.net/anonbib/#clog-the-queue">Don't
en/volunteer.wml 736) Clog the Queue</a> too.</li>

volunteer.html   737) <li>The "routing zones attack": most of the literature thinks of
volunteer.html   738) the network path between Alice and her entry node (and between the
volunteer.html   739) exit node and Bob) as a single link on some graph. In practice,
volunteer.html   740) though, the path traverses many autonomous systems (ASes), and <a
volunteer.html   741) href="http://freehaven.net/anonbib/#feamster:wpes2004">it's not uncommon
volunteer.html   742) that the same AS appears on both the entry path and the exit path</a>.
volunteer.html   743) Unfortunately, to accurately predict whether a given Alice, entry,
volunteer.html   744) exit, Bob quad will be dangerous, we need to download an entire Internet
volunteer.html   745) routing zone and perform expensive operations on it. Are there practical
volunteer.html   746) approximations, such as avoiding IP addresses in the same /8 network?</li>

en/volunteer.wml 747) <li>Other research questions regarding geographic diversity consider
en/volunteer.wml 748) the tradeoff between choosing an efficient circuit and choosing a random

en/volunteer.wml 749) circuit. Look at Stephen Rollyson's <a

en/volunteer.wml 750) href="http://swiki.cc.gatech.edu:8080/ugResearch/uploads/7/ImprovingTor.pdf">position
en/volunteer.wml 751) paper</a> on how to discard particularly slow choices without hurting

en/volunteer.wml 752) anonymity "too much". This line of reasoning needs more work and more
en/volunteer.wml 753) thinking, but it looks very promising.</li>

en/volunteer.wml 754) <li>Tor doesn't work very well when relays have asymmetric bandwidth

volunteer.html   755) (e.g. cable or DSL). Because Tor has separate TCP connections between
volunteer.html   756) each hop, if the incoming bytes are arriving just fine and the outgoing
volunteer.html   757) bytes are all getting dropped on the floor, the TCP push-back mechanisms
volunteer.html   758) don't really transmit this information back to the incoming streams.
volunteer.html   759) Perhaps Tor should detect when it's dropping a lot of outgoing packets,
volunteer.html   760) and rate-limit incoming streams to regulate this itself? I can imagine
volunteer.html   761) a build-up and drop-off scheme where we pick a conservative rate-limit,
volunteer.html   762) slowly increase it until we get lost packets, back off, repeat. We
volunteer.html   763) need somebody who's good with networks to simulate this and help design
volunteer.html   764) solutions; and/or we need to understand the extent of the performance
volunteer.html   765) degradation, and use this as motivation to reconsider UDP transport.</li>
volunteer.html   766) <li>A related topic is congestion control. Is our
volunteer.html   767) current design sufficient once we have heavy use? Maybe
volunteer.html   768) we should experiment with variable-sized windows rather
volunteer.html   769) than fixed-size windows? That seemed to go well in an <a
volunteer.html   770) href="http://www.psc.edu/networking/projects/hpn-ssh/theory.php">ssh
volunteer.html   771) throughput experiment</a>. We'll need to measure and tweak, and maybe
volunteer.html   772) overhaul if the results are good.</li>

en/volunteer.wml 773) <li>Our censorship-resistance goals include preventing
en/volunteer.wml 774) an attacker who's looking at Tor traffic on the wire from <a

en/volunteer.wml 775) href="<svnsandbox>doc/design-paper/blocking.html#sec:network-fingerprint">distinguishing

en/volunteer.wml 776) it from normal SSL traffic</a>. Obviously we can't achieve perfect
en/volunteer.wml 777) steganography and still remain usable, but for a first step we'd like to
en/volunteer.wml 778) block any attacks that can win by observing only a few packets. One of
en/volunteer.wml 779) the remaining attacks we haven't examined much is that Tor cells are 512
en/volunteer.wml 780) bytes, so the traffic on the wire may well be a multiple of 512 bytes.
en/volunteer.wml 781) How much does the batching and overhead in TLS records blur this on the
en/volunteer.wml 782) wire? Do different buffer flushing strategies in Tor affect this? Could
en/volunteer.wml 783) a bit of padding help a lot, or is this an attack we must accept?</li>

volunteer.html   784) <li>Tor circuits are built one hop at a time, so in theory we have the
volunteer.html   785) ability to make some streams exit from the second hop, some from the
volunteer.html   786) third, and so on. This seems nice because it breaks up the set of exiting

en/volunteer.wml 787) streams that a given relay can see. But if we want each stream to be safe,

volunteer.html   788) the "shortest" path should be at least 3 hops long by our current logic, so
volunteer.html   789) the rest will be even longer. We need to examine this performance / security
volunteer.html   790) tradeoff.</li>

en/volunteer.wml 791) <li>It's not that hard to DoS Tor relays or directory authorities. Are client

volunteer.html   792) puzzles the right answer? What other practical approaches are there? Bonus
volunteer.html   793) if they're backward-compatible with the current Tor protocol.</li>

en/volunteer.wml 794) <li>Programs like <a

en/volunteer.wml 795) href="<page torbutton/index>">Torbutton</a> aim to hide

en/volunteer.wml 796) your browser's UserAgent string by replacing it with a uniform answer for
en/volunteer.wml 797) every Tor user. That way the attacker can't splinter Tor's anonymity set
en/volunteer.wml 798) by looking at that header. It tries to pick a string that is commonly used
en/volunteer.wml 799) by non-Tor users too, so it doesn't stand out. Question one: how badly
en/volunteer.wml 800) do we hurt ourselves by periodically updating the version of Firefox
en/volunteer.wml 801) that Torbutton claims to be? If we update it too often, we splinter the
en/volunteer.wml 802) anonymity sets ourselves. If we don't update it often enough, then all the
en/volunteer.wml 803) Tor users stand out because they claim to be running a quite old version
en/volunteer.wml 804) of Firefox. The answer here probably depends on the Firefox versions seen
en/volunteer.wml 805) in the wild. Question two: periodically people ask us to cycle through N
en/volunteer.wml 806) UserAgent strings rather than stick with one. Does this approach help,
en/volunteer.wml 807) hurt, or not matter? Consider: cookies and recognizing Torbutton users
en/volunteer.wml 808) by their rotating UserAgents; malicious websites who only attack certain
en/volunteer.wml 809) browsers; and whether the answers to question one impact this answer.
en/volunteer.wml 810) </li>

en/volunteer.wml 811) <li>Right now Tor clients are willing to reuse a given circuit for ten
en/volunteer.wml 812) minutes after it's first used. The goal is to avoid loading down the
en/volunteer.wml 813) network with too many circuit extend operations, yet to also avoid having
en/volunteer.wml 814) clients use the same circuit for so long that the exit node can build a
en/volunteer.wml 815) useful pseudonymous profile of them. Alas, ten minutes is probably way
en/volunteer.wml 816) too long, especially if connections from multiple protocols (e.g. IM and
en/volunteer.wml 817) web browsing) are put on the same circuit. If we keep fixed the overall
en/volunteer.wml 818) number of circuit extends that the network needs to do, are there more
en/volunteer.wml 819) efficient and/or safer ways for clients to allocate streams to circuits,
en/volunteer.wml 820) or for clients to build preemptive circuits? Perhaps this research item
en/volunteer.wml 821) needs to start with gathering some traces of what connections typical
en/volunteer.wml 822) clients try to launch, so you have something realistic to try to optimize.
en/volunteer.wml 823) </li>
en/volunteer.wml 824) <li>How many bridge relays do you need to know to maintain
en/volunteer.wml 825) reachability? We should measure the churn in our bridges. If there is
en/volunteer.wml 826) lots of churn, are there ways to keep bridge users more likely to stay
en/volunteer.wml 827) connected?
en/volunteer.wml 828) </li>

volunteer.html   829) </ol>
volunteer.html   830) 

en/volunteer.wml 831) <p>

en/volunteer.wml 832) <a href="<page contact>">Let us know</a> if you've made progress on any
en/volunteer.wml 833) of these!

en/volunteer.wml 834) </p>

volunteer.html   835) 

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