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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 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) <h2><a class="anchor" href="#Coding">Coding and Design</a></h2>

volunteer.html    92) <ol>

en/volunteer.wml  93) <li>Tor relays don't work well on Windows XP. On

en/volunteer.wml  94) Windows, Tor uses the standard <tt>select()</tt> system

en/volunteer.wml  95) call, which uses space in the non-page pool. This means

en/volunteer.wml  96) that a medium sized Tor relay will empty the non-page pool, <a

en/volunteer.wml  97) href="https://wiki.torproject.org/noreply/TheOnionRouter/WindowsBufferProblems">causing

en/volunteer.wml  98) havoc and system crashes</a>. We should probably be using overlapped IO

en/volunteer.wml  99) instead. One solution would be to teach <a
en/volunteer.wml 100) href="http://www.monkey.org/~provos/libevent/">libevent</a> how to use
en/volunteer.wml 101) overlapped IO rather than select() on Windows, and then adapt Tor to

en/volunteer.wml 102) the new libevent interface. Christian King made a
en/volunteer.wml 103) <a href="https://tor-svn.freehaven.net/svn/libevent-urz/trunk/">good
en/volunteer.wml 104) start</a> on this last summer.</li>
en/volunteer.wml 105) <li>How can we make the <a
en/volunteer.wml 106) href="http://anonymityanywhere.com/incognito/">Incognito LiveCD</a>
en/volunteer.wml 107) easier to maintain, improve, and document?</li>

en/volunteer.wml 108) <li>Our preferred graphical front-end for Tor, named
en/volunteer.wml 109) <a href="http://vidalia-project.net/">Vidalia</a>, needs all sorts
en/volunteer.wml 110) of development work.</li>

en/volunteer.wml 111) <li>We need to actually start building our <a href="<page
en/volunteer.wml 112) documentation>#DesignDoc">blocking-resistance design</a>. This involves

en/volunteer.wml 113) fleshing out the design, modifying many different pieces of Tor, adapting
en/volunteer.wml 114) <a href="http://vidalia-project.net/">Vidalia</a> so it supports the
en/volunteer.wml 115) new features, and planning for deployment.</li>

en/volunteer.wml 116) <li>We need a flexible simulator framework for studying end-to-end
en/volunteer.wml 117) traffic confirmation attacks. Many researchers have whipped up ad hoc
en/volunteer.wml 118) simulators to support their intuition either that the attacks work
en/volunteer.wml 119) really well or that some defense works great. Can we build a simulator
en/volunteer.wml 120) that's clearly documented and open enough that everybody knows it's
en/volunteer.wml 121) giving a reasonable answer? This will spur a lot of new research.
en/volunteer.wml 122) See the entry <a href="#Research">below</a> on confirmation attacks for
en/volunteer.wml 123) details on the research side of this task &mdash; who knows, when it's
en/volunteer.wml 124) done maybe you can help write a paper or three also.</li>

en/volunteer.wml 125) <li>We need a distributed testing framework. We have unit tests,

en/volunteer.wml 126) but it would be great to have a script that starts up a Tor network, uses
en/volunteer.wml 127) it for a while, and verifies that at least parts of it are working.</li>

en/volunteer.wml 128) <li>Help Mike Perry on his <a

en/volunteer.wml 129) href="https://www.torproject.org/svn/torflow/">TorFlow</a>
en/volunteer.wml 130) library (<a href="https://www.torproject.org/svn/torflow/TODO">TODO</a>):

en/volunteer.wml 131) it's a python library that uses the <a

en/volunteer.wml 132) href="https://www.torproject.org/svn/torctl/doc/howto.txt">Tor controller

en/volunteer.wml 133) protocol</a> to instruct Tor to build circuits in a variety of ways,
en/volunteer.wml 134) and then it measures performance and tries to detect anomalies.</li>

en/volunteer.wml 135) <li>Tor 0.1.1.x and later include support for hardware crypto accelerators

en/volunteer.wml 136) via OpenSSL. Nobody has ever tested it, though. Does somebody want to get

volunteer.html   137) a card and let us know how it goes?</li>

volunteer.html   138) <li>Perform a security analysis of Tor with <a
volunteer.html   139) href="http://en.wikipedia.org/wiki/Fuzz_testing">"fuzz"</a>. Determine

en/volunteer.wml 140) if there are good fuzzing libraries out there for what we want. Win fame by

volunteer.html   141) getting credit when we put out a new release because of you!</li>

volunteer.html   142) <li>Tor uses TCP for transport and TLS for link
volunteer.html   143) encryption. This is nice and simple, but it means all cells
volunteer.html   144) on a link are delayed when a single packet gets dropped, and
volunteer.html   145) it means we can only reasonably support TCP streams. We have a <a

en/volunteer.wml 146) href="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#TransportIPnotTCP">list

en/volunteer.wml 147) of reasons why we haven't shifted to UDP transport</a>, but it would
en/volunteer.wml 148) be great to see that list get shorter. We also have a proposed <a

en/volunteer.wml 149) href="<svnsandbox>doc/spec/proposals/100-tor-spec-udp.txt">specification
en/volunteer.wml 150) for Tor and

en/volunteer.wml 151) UDP</a> &mdash; please let us know what's wrong with it.</li>

volunteer.html   152) <li>We're not that far from having IPv6 support for destination addresses
volunteer.html   153) (at exit nodes). If you care strongly about IPv6, that's probably the
volunteer.html   154) first place to start.</li>

en/volunteer.wml 155) <li>Don't like any of these? Look at the <a

en/volunteer.wml 156) href="<svnsandbox>doc/design-paper/roadmap-future.pdf">Tor development

en/volunteer.wml 157) roadmap</a> for more ideas.</li>
en/volunteer.wml 158) <li>Don't see your idea here? We probably need it anyway! Contact
en/volunteer.wml 159) us and find out.</li>

volunteer.html   160) </ol>
volunteer.html   161) 

en/volunteer.wml 162) <a id="Research"></a>
en/volunteer.wml 163) <h2><a class="anchor" href="#Research">Research</a></h2>

volunteer.html   164) <ol>

volunteer.html   165) <li>The "website fingerprinting attack": make a list of a few
volunteer.html   166) hundred popular websites, download their pages, and make a set of
volunteer.html   167) "signatures" for each site. Then observe a Tor client's traffic. As
volunteer.html   168) you watch him receive data, you quickly approach a guess about which
volunteer.html   169) (if any) of those sites he is visiting. First, how effective is
volunteer.html   170) this attack on the deployed Tor codebase? Then start exploring
volunteer.html   171) defenses: for example, we could change Tor's cell size from 512
volunteer.html   172) bytes to 1024 bytes, we could employ padding techniques like <a
volunteer.html   173) href="http://freehaven.net/anonbib/#timing-fc2004">defensive dropping</a>,
volunteer.html   174) or we could add traffic delays. How much of an impact do these have,
volunteer.html   175) and how much usability impact (using some suitable metric) is there from
volunteer.html   176) a successful defense in each case?</li>

volunteer.html   177) <li>The "end-to-end traffic confirmation attack":
volunteer.html   178) by watching traffic at Alice and at Bob, we can <a
volunteer.html   179) href="http://freehaven.net/anonbib/#danezis:pet2004">compare
volunteer.html   180) traffic signatures and become convinced that we're watching the same
volunteer.html   181) stream</a>. So far Tor accepts this as a fact of life and assumes this
volunteer.html   182) attack is trivial in all cases. First of all, is that actually true? How
volunteer.html   183) much traffic of what sort of distribution is needed before the adversary
volunteer.html   184) is confident he has won? Are there scenarios (e.g. not transmitting much)
volunteer.html   185) that slow down the attack? Do some traffic padding or traffic shaping
volunteer.html   186) schemes work better than others?</li>

volunteer.html   187) <li>The "routing zones attack": most of the literature thinks of
volunteer.html   188) the network path between Alice and her entry node (and between the
volunteer.html   189) exit node and Bob) as a single link on some graph. In practice,
volunteer.html   190) though, the path traverses many autonomous systems (ASes), and <a
volunteer.html   191) href="http://freehaven.net/anonbib/#feamster:wpes2004">it's not uncommon
volunteer.html   192) that the same AS appears on both the entry path and the exit path</a>.
volunteer.html   193) Unfortunately, to accurately predict whether a given Alice, entry,
volunteer.html   194) exit, Bob quad will be dangerous, we need to download an entire Internet
volunteer.html   195) routing zone and perform expensive operations on it. Are there practical
volunteer.html   196) approximations, such as avoiding IP addresses in the same /8 network?</li>

en/volunteer.wml 197) <li>Other research questions regarding geographic diversity consider
en/volunteer.wml 198) the tradeoff between choosing an efficient circuit and choosing a random

en/volunteer.wml 199) circuit. Look at Stephen Rollyson's <a

en/volunteer.wml 200) href="http://swiki.cc.gatech.edu:8080/ugResearch/uploads/7/ImprovingTor.pdf">position
en/volunteer.wml 201) paper</a> on how to discard particularly slow choices without hurting

en/volunteer.wml 202) anonymity "too much". This line of reasoning needs more work and more
en/volunteer.wml 203) thinking, but it looks very promising.</li>

en/volunteer.wml 204) <li>Tor doesn't work very well when relays have asymmetric bandwidth

volunteer.html   205) (e.g. cable or DSL). Because Tor has separate TCP connections between
volunteer.html   206) each hop, if the incoming bytes are arriving just fine and the outgoing
volunteer.html   207) bytes are all getting dropped on the floor, the TCP push-back mechanisms
volunteer.html   208) don't really transmit this information back to the incoming streams.
volunteer.html   209) Perhaps Tor should detect when it's dropping a lot of outgoing packets,
volunteer.html   210) and rate-limit incoming streams to regulate this itself? I can imagine
volunteer.html   211) a build-up and drop-off scheme where we pick a conservative rate-limit,
volunteer.html   212) slowly increase it until we get lost packets, back off, repeat. We
volunteer.html   213) need somebody who's good with networks to simulate this and help design
volunteer.html   214) solutions; and/or we need to understand the extent of the performance
volunteer.html   215) degradation, and use this as motivation to reconsider UDP transport.</li>
volunteer.html   216) <li>A related topic is congestion control. Is our
volunteer.html   217) current design sufficient once we have heavy use? Maybe
volunteer.html   218) we should experiment with variable-sized windows rather
volunteer.html   219) than fixed-size windows? That seemed to go well in an <a
volunteer.html   220) href="http://www.psc.edu/networking/projects/hpn-ssh/theory.php">ssh
volunteer.html   221) throughput experiment</a>. We'll need to measure and tweak, and maybe
volunteer.html   222) overhaul if the results are good.</li>

volunteer.html   223) <li>To let dissidents in remote countries use Tor without being blocked
volunteer.html   224) at their country's firewall, we need a way to get tens of thousands of
volunteer.html   225) relays, not just a few hundred. We can imagine a Tor client GUI that

en/volunteer.wml 226) has a "Tor for Freedom" button at the top that opens a port and relays a

volunteer.html   227) few KB/s of traffic into the Tor network. (A few KB/s shouldn't be too
volunteer.html   228) much hassle, and there are few abuse issues since they're not being exit
volunteer.html   229) nodes.) But how do we distribute a list of these volunteer clients to the
volunteer.html   230) good dissidents in an automated way that doesn't let the country-level
volunteer.html   231) firewalls intercept and enumerate them? Probably needs to work on a

en/volunteer.wml 232) human-trust level. See our <a href="<page documentation>#DesignDoc">early
en/volunteer.wml 233) blocking-resistance design document</a> and our
en/volunteer.wml 234) <a

en/volunteer.wml 235) href="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#BlockingResistance">FAQ

en/volunteer.wml 236) entry</a> on this, and then read the <a
en/volunteer.wml 237) href="http://freehaven.net/anonbib/topic.html#Communications_20Censorship">censorship
en/volunteer.wml 238) resistance section of anonbib</a>.</li>

volunteer.html   239) <li>Tor circuits are built one hop at a time, so in theory we have the
volunteer.html   240) ability to make some streams exit from the second hop, some from the
volunteer.html   241) third, and so on. This seems nice because it breaks up the set of exiting

en/volunteer.wml 242) streams that a given relay can see. But if we want each stream to be safe,

volunteer.html   243) the "shortest" path should be at least 3 hops long by our current logic, so
volunteer.html   244) the rest will be even longer. We need to examine this performance / security
volunteer.html   245) tradeoff.</li>

en/volunteer.wml 246) <li>It's not that hard to DoS Tor relays or directory authorities. Are client

volunteer.html   247) puzzles the right answer? What other practical approaches are there? Bonus
volunteer.html   248) if they're backward-compatible with the current Tor protocol.</li>

volunteer.html   249) </ol>
volunteer.html   250) 

en/volunteer.wml 251) <a href="<page contact>">Let us know</a> if you've made progress on any
en/volunteer.wml 252) of these!

volunteer.html   253) 

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