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

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

volunteer.html    10) <ol>

en/volunteer.wml  11) <li>Please consider <a href="<page docs/tor-doc-server>">running

volunteer.html    12) a server</a> to help the Tor network grow.</li>

en/volunteer.wml  13) <li>Take a look at the <a href="<page gui/index>">Tor GUI Competition</a>, and

en/volunteer.wml  14) contribute to making Tor's interface
en/volunteer.wml  15) and usability better. Free Tor T-shirt for each submission!</li>

en/volunteer.wml  16) <li>Tell your friends! Get them to run servers. Get them to run hidden

volunteer.html    17) services. Get them to tell their friends.</li>

en/volunteer.wml  18) <li>We are looking for funding and sponsors. If you like Tor's goals, please

en/volunteer.wml  19)   <a href="<page donate>">take a moment to donate to support further
en/volunteer.wml  20)   Tor development</a>. Also, if you know any

en/volunteer.wml  21)   companies, NGOs, agencies, or other organizations that want communications

en/volunteer.wml  22)   security, let them know about us.</li>

volunteer.html    23) </ol>
volunteer.html    24) 

en/volunteer.wml  25) <a id="Bugs"></a>
en/volunteer.wml  26) <h2><a class="anchor" href="#Bugs">Critical bugs</a></h2>
en/volunteer.wml  27) <ol>
en/volunteer.wml  28) <li>Tor servers are not stable on Windows XP currently,
en/volunteer.wml  29) because we try to use hundreds of sockets, and the
en/volunteer.wml  30) Windows kernel doesn't seem capable of handling this. <a
en/volunteer.wml  31) href="http://wiki.noreply.org/noreply/TheOnionRouter/WindowsBufferProblems">Please

en/volunteer.wml  32) help us solve this!</a> Probably the best solution is to teach libevent
en/volunteer.wml  33) how to use overlapped IO rather than select() on Windows, and then adapt
en/volunteer.wml  34) Tor to the new libevent interface.</li>

en/volunteer.wml  35) </ol>
en/volunteer.wml  36) 

en/volunteer.wml  37) <a id="Usability"></a>

en/volunteer.wml  38) <h2><a class="anchor" href="#Usability">Supporting Applications</a></h2>

volunteer.html    39) <ol>

en/volunteer.wml  40) <li>We need good ways to intercept DNS requests so they don't "leak" their
en/volunteer.wml  41) request to a local observer while we're trying to be anonymous. (This
en/volunteer.wml  42) happens because the application does the DNS resolve before going to
en/volunteer.wml  43) the SOCKS proxy.)</li>
en/volunteer.wml  44) <ul>
en/volunteer.wml  45) <li>We need to <a
en/volunteer.wml  46) href="http://wiki.noreply.org/noreply/TheOnionRouter/TSocksPatches">apply
en/volunteer.wml  47) all our tsocks patches</a> and maintain a new fork. We'll host it if
en/volunteer.wml  48) you want.</li>
en/volunteer.wml  49) <li>We should patch Dug Song's "dsocks" program to use Tor's
en/volunteer.wml  50) <i>mapaddress</i> commands from the controller interface, so we
en/volunteer.wml  51) don't waste a whole round-trip inside Tor doing the resolve before
en/volunteer.wml  52) connecting.</li>
en/volunteer.wml  53) <li>We need to make our <i>torify</i> script detect which of tsocks or
en/volunteer.wml  54) dsocks is installed, and call them appropriately. This probably means
en/volunteer.wml  55) unifying their interfaces, and might involve sharing code between them
en/volunteer.wml  56) or discarding one entirely.</li>
en/volunteer.wml  57) </ul>

volunteer.html    58) <li>People running servers tell us they want to have one BandwidthRate
volunteer.html    59) during some part of the day, and a different BandwidthRate at other parts
volunteer.html    60) of the day. Rather than coding this inside Tor, we should have a little

en/volunteer.wml  61) script that speaks via the <a href="<page gui/index>">Tor Controller Interface</a>,

volunteer.html    62) and does a setconf to change the bandwidth rate. Perhaps it would run out
volunteer.html    63) of cron, or perhaps it would sleep until appropriate times and then do
volunteer.html    64) its tweak (that's probably more portable). Can somebody write one for us

en/volunteer.wml  65) and we'll put it into <a href="<svnsandbox>contrib/">contrib/</a>?

en/volunteer.wml  66) This is a good entry for the <a href="<page gui/index>">Tor GUI
en/volunteer.wml  67) competition</a>.</li>
en/volunteer.wml  68) <li>Tor can <a

volunteer.html    69) href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#ChooseEntryExit">exit

en/volunteer.wml  70) the Tor network from a particular exit node</a>, but we should be able
en/volunteer.wml  71) to specify just a country and have something automatically pick. The
en/volunteer.wml  72) best bet is to fetch Blossom's directory also, and run a local Blossom
en/volunteer.wml  73) client that fetches this directory securely (via Tor and checking its
en/volunteer.wml  74) signature), intercepts <tt>.country.blossom</tt> hostnames, and does
en/volunteer.wml  75) the right thing.</li>

volunteer.html    76) <li>Speaking of geolocation data, somebody should draw a map of the Earth
volunteer.html    77) with a pin-point for each Tor server. Bonus points if it updates as the

en/volunteer.wml  78) network grows and changes. Unfortunately, the easy ways to do this involve
en/volunteer.wml  79) sending all the data to Google and having them draw the map for you. How
en/volunteer.wml  80) much does this impact privacy, and do we have any other good options?</li>

volunteer.html    81) </ol>
volunteer.html    82) 

en/volunteer.wml  83) <a id="Documentation"></a>
en/volunteer.wml  84) <h2><a class="anchor" href="#Documentation">Documentation</a></h2>

volunteer.html    85) <ol>

en/volunteer.wml  86) <li>We hear that Tor users can fall victim to anonymity-breaking attacks
en/volunteer.wml  87) from javascript, java, activex, flash, etc, if they don't disable
en/volunteer.wml  88) them. Are there plugins out there (like NoScript for Firefox) that make
en/volunteer.wml  89) it easier for users to manage this risk? What is the risk exactly?</li>
en/volunteer.wml  90) <li>Is there a full suite of plugins that will replace all of Privoxy's
en/volunteer.wml  91) functionality for Firefox 1.5+? We hear Tor is much faster when you take
en/volunteer.wml  92) Privoxy out of the loop.</li>
en/volunteer.wml  93) <li>Please help Matt Edman with the documentation and how-tos for his
en/volunteer.wml  94) <a href="http://vidalia-project.net/">Tor Controller</a>.</li>

en/volunteer.wml  95) <li>Evaluate and document
en/volunteer.wml  96) <a href="http://wiki.noreply.org/wiki/TheOnionRouter/TorifyHOWTO">our
en/volunteer.wml  97) list of programs</a> that can be configured to use Tor.</li>

volunteer.html    98) <li>We need better documentation for dynamically intercepting

en/volunteer.wml  99) connections and sending them through Tor. tsocks (Linux), dsocks (BSD),
en/volunteer.wml 100) and freecap (Windows) seem to be good candidates.</li>

en/volunteer.wml 101) <li>We have a huge list of <a href="http://wiki.noreply.org/noreply/TheOnionRouter/SupportPrograms">potentially useful

volunteer.html   102) programs that interface to Tor</a>. Which ones are useful in which
volunteer.html   103) situations? Please help us test them out and document your results.</li>

en/volunteer.wml 104) <li>Help translate the web page and documentation into other
en/volunteer.wml 105) languages. See the <a href="<page translation>">translation
en/volunteer.wml 106) guidelines</a> if you want to help out. We also need people to help
en/volunteer.wml 107) maintain the existing Italian, French, and Swedish translations -
en/volunteer.wml 108) see the <a href="<page translation-status>">translation status
en/volunteer.wml 109) overview</a>.</li>

volunteer.html   110) </ol>
volunteer.html   111) 

en/volunteer.wml 112) <a id="Coding"></a>
en/volunteer.wml 113) <h2><a class="anchor" href="#Coding">Coding and Design</a></h2>

volunteer.html   114) <ol>

en/volunteer.wml 115) <li>Right now the hidden service descriptors are being stored on just a
en/volunteer.wml 116) few directory servers. This is bad for privacy and bad for robustness. To
en/volunteer.wml 117) get more robustness, we're going to need to make hidden service
en/volunteer.wml 118) descriptors even less private because we're going to have to mirror them
en/volunteer.wml 119) onto many places. Ideally we'd like to separate the storage/lookup system
en/volunteer.wml 120) from the Tor directory servers entirely. The first problem is that we need
en/volunteer.wml 121) to design a new hidden service descriptor format to a) be ascii rather
en/volunteer.wml 122) than binary for convenience; b) keep the list of introduction points
en/volunteer.wml 123) encrypted unless you know the <tt>.onion</tt> address, so the directory
en/volunteer.wml 124) can't learn them; and c) allow the directories to verify the timestamp
en/volunteer.wml 125) and signature on a hidden service descriptor so they can't be tricked
en/volunteer.wml 126) into giving out fake ones. Second, any reliable distributed storage
en/volunteer.wml 127) system will do, as long as it allows authenticated updates, but as far
en/volunteer.wml 128) as we know no implemented DHT code supports authenticated updates.</li>

volunteer.html   129) <li>Tor exit servers need to do many DNS resolves in parallel. But
volunteer.html   130) gethostbyname() is poorly designed --- it blocks until it has finished

volunteer.html   131) resolving a query --- so it requires its own thread or process. So Tor
volunteer.html   132) is forced to spawn many separate DNS "worker" threads. There are some
volunteer.html   133) asynchronous DNS libraries out there, but historically they are buggy and

volunteer.html   134) abandoned. Are any of them stable, fast, clean, and free software? (Remember,
volunteer.html   135) Tor uses OpenSSL, and OpenSSL is (probably) not compatible with the GPL, so
volunteer.html   136) any GPL libraries are out of the running.) If so

volunteer.html   137) (or if we can make that so), we should integrate them into Tor. See <a

volunteer.html   138) href="http://archives.seul.org/or/talk/Sep-2005/msg00001.html">Agl's

volunteer.html   139) post</a> for one potential approach. Also see
volunteer.html   140) <a href="http://daniel.haxx.se/projects/c-ares/">c-ares</a> and
volunteer.html   141) <a href="http://www.monkey.org/~provos/libdnsres/">libdnsres</a>.
volunteer.html   142) </li>

volunteer.html   143) <li>Tor 0.1.1.x includes support for hardware crypto accelerators via
volunteer.html   144) OpenSSL. Nobody has ever tested it, though. Does somebody want to get
volunteer.html   145) a card and let us know how it goes?</li>

volunteer.html   146) <li>Because Tor servers need to store-and-forward each cell they handle,
volunteer.html   147) high-bandwidth Tor servers end up using dozens of megabytes of memory
volunteer.html   148) just for buffers. We need better heuristics for when to shrink/expand
volunteer.html   149) buffers. Maybe this should be modelled after the Linux kernel buffer
volunteer.html   150) design, where you have many smaller buffers that link to each other,
volunteer.html   151) rather than monolithic buffers?</li>

volunteer.html   152) <li>Implement reverse DNS requests inside Tor (already specified in

en/volunteer.wml 153) Section 5.4 of <a href="<svnsandbox>doc/tor-spec.txt">tor-spec.txt</a>).</li>

volunteer.html   154) <li>Perform a security analysis of Tor with <a
volunteer.html   155) href="http://en.wikipedia.org/wiki/Fuzz_testing">"fuzz"</a>. Determine

en/volunteer.wml 156) if there are good fuzzing libraries out there for what we want. Win fame by

volunteer.html   157) getting credit when we put out a new release because of you!</li>

en/volunteer.wml 158) <li>How hard is it to patch bind or a
en/volunteer.wml 159) DNS proxy to redirect requests to Tor via our <a
en/volunteer.wml 160) href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#CompatibleApplications">tor-resolve
en/volunteer.wml 161) socks extension</a>? dsocks already does this on BSD. What about to
en/volunteer.wml 162) convert UDP DNS requests to TCP requests and send them through Tor?</li>

volunteer.html   163) <li>Tor uses TCP for transport and TLS for link
volunteer.html   164) encryption. This is nice and simple, but it means all cells
volunteer.html   165) on a link are delayed when a single packet gets dropped, and
volunteer.html   166) it means we can only reasonably support TCP streams. We have a <a
volunteer.html   167) href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#TransportIPnotTCP">list

en/volunteer.wml 168) of reasons why we haven't shifted to UDP transport</a>, but it would
en/volunteer.wml 169) be great to see that list get shorter. We also have a proposed <a

en/volunteer.wml 170) href="<svnsandbox>doc/tor-spec-udp.txt">specification for Tor and

en/volunteer.wml 171) UDP</a> &mdash; please let us know what's wrong with it.</li>

volunteer.html   172) <li>We're not that far from having IPv6 support for destination addresses
volunteer.html   173) (at exit nodes). If you care strongly about IPv6, that's probably the
volunteer.html   174) first place to start.</li>

volunteer.html   175) </ol>
volunteer.html   176) 

en/volunteer.wml 177) <a id="Research"></a>
en/volunteer.wml 178) <h2><a class="anchor" href="#Research">Research</a></h2>

volunteer.html   179) <ol>

volunteer.html   180) <li>The "website fingerprinting attack": make a list of a few
volunteer.html   181) hundred popular websites, download their pages, and make a set of
volunteer.html   182) "signatures" for each site. Then observe a Tor client's traffic. As
volunteer.html   183) you watch him receive data, you quickly approach a guess about which
volunteer.html   184) (if any) of those sites he is visiting. First, how effective is
volunteer.html   185) this attack on the deployed Tor codebase? Then start exploring
volunteer.html   186) defenses: for example, we could change Tor's cell size from 512
volunteer.html   187) bytes to 1024 bytes, we could employ padding techniques like <a
volunteer.html   188) href="http://freehaven.net/anonbib/#timing-fc2004">defensive dropping</a>,
volunteer.html   189) or we could add traffic delays. How much of an impact do these have,
volunteer.html   190) and how much usability impact (using some suitable metric) is there from
volunteer.html   191) a successful defense in each case?</li>

volunteer.html   192) <li>The "end-to-end traffic confirmation attack":
volunteer.html   193) by watching traffic at Alice and at Bob, we can <a
volunteer.html   194) href="http://freehaven.net/anonbib/#danezis:pet2004">compare
volunteer.html   195) traffic signatures and become convinced that we're watching the same
volunteer.html   196) stream</a>. So far Tor accepts this as a fact of life and assumes this
volunteer.html   197) attack is trivial in all cases. First of all, is that actually true? How
volunteer.html   198) much traffic of what sort of distribution is needed before the adversary
volunteer.html   199) is confident he has won? Are there scenarios (e.g. not transmitting much)
volunteer.html   200) that slow down the attack? Do some traffic padding or traffic shaping
volunteer.html   201) schemes work better than others?</li>

volunteer.html   202) <li>The "routing zones attack": most of the literature thinks of
volunteer.html   203) the network path between Alice and her entry node (and between the
volunteer.html   204) exit node and Bob) as a single link on some graph. In practice,
volunteer.html   205) though, the path traverses many autonomous systems (ASes), and <a
volunteer.html   206) href="http://freehaven.net/anonbib/#feamster:wpes2004">it's not uncommon
volunteer.html   207) that the same AS appears on both the entry path and the exit path</a>.
volunteer.html   208) Unfortunately, to accurately predict whether a given Alice, entry,
volunteer.html   209) exit, Bob quad will be dangerous, we need to download an entire Internet
volunteer.html   210) routing zone and perform expensive operations on it. Are there practical
volunteer.html   211) approximations, such as avoiding IP addresses in the same /8 network?</li>

volunteer.html   212) <li>Tor doesn't work very well when servers have asymmetric bandwidth
volunteer.html   213) (e.g. cable or DSL). Because Tor has separate TCP connections between
volunteer.html   214) each hop, if the incoming bytes are arriving just fine and the outgoing
volunteer.html   215) bytes are all getting dropped on the floor, the TCP push-back mechanisms
volunteer.html   216) don't really transmit this information back to the incoming streams.
volunteer.html   217) Perhaps Tor should detect when it's dropping a lot of outgoing packets,
volunteer.html   218) and rate-limit incoming streams to regulate this itself? I can imagine
volunteer.html   219) a build-up and drop-off scheme where we pick a conservative rate-limit,
volunteer.html   220) slowly increase it until we get lost packets, back off, repeat. We
volunteer.html   221) need somebody who's good with networks to simulate this and help design
volunteer.html   222) solutions; and/or we need to understand the extent of the performance
volunteer.html   223) degradation, and use this as motivation to reconsider UDP transport.</li>
volunteer.html   224) <li>A related topic is congestion control. Is our
volunteer.html   225) current design sufficient once we have heavy use? Maybe
volunteer.html   226) we should experiment with variable-sized windows rather
volunteer.html   227) than fixed-size windows? That seemed to go well in an <a
volunteer.html   228) href="http://www.psc.edu/networking/projects/hpn-ssh/theory.php">ssh
volunteer.html   229) throughput experiment</a>. We'll need to measure and tweak, and maybe
volunteer.html   230) overhaul if the results are good.</li>

volunteer.html   231) <li>To let dissidents in remote countries use Tor without being blocked
volunteer.html   232) at their country's firewall, we need a way to get tens of thousands of
volunteer.html   233) relays, not just a few hundred. We can imagine a Tor client GUI that
volunteer.html   234) has a "help China" button at the top that opens a port and relays a
volunteer.html   235) few KB/s of traffic into the Tor network. (A few KB/s shouldn't be too
volunteer.html   236) much hassle, and there are few abuse issues since they're not being exit
volunteer.html   237) nodes.) But how do we distribute a list of these volunteer clients to the
volunteer.html   238) good dissidents in an automated way that doesn't let the country-level
volunteer.html   239) firewalls intercept and enumerate them? Probably needs to work on a

en/volunteer.wml 240) human-trust level. See our <a
en/volunteer.wml 241) href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#China">FAQ
en/volunteer.wml 242) entry</a> on this, and then read the <a
en/volunteer.wml 243) href="http://freehaven.net/anonbib/topic.html#Communications_20Censorship">censorship
en/volunteer.wml 244) resistance section of anonbib</a>.</li>

volunteer.html   245) <li>Tor circuits are built one hop at a time, so in theory we have the
volunteer.html   246) ability to make some streams exit from the second hop, some from the
volunteer.html   247) third, and so on. This seems nice because it breaks up the set of exiting
volunteer.html   248) streams that a given server can see. But if we want each stream to be safe,
volunteer.html   249) the "shortest" path should be at least 3 hops long by our current logic, so
volunteer.html   250) the rest will be even longer. We need to examine this performance / security
volunteer.html   251) tradeoff.</li>
volunteer.html   252) <li>It's not that hard to DoS Tor servers or dirservers. Are client
volunteer.html   253) puzzles the right answer? What other practical approaches are there? Bonus
volunteer.html   254) if they're backward-compatible with the current Tor protocol.</li>

volunteer.html   255) </ol>
volunteer.html   256) 

en/volunteer.wml 257) <a href="<page contact>">Let us know</a> if you've made progress on any
en/volunteer.wml 258) of these!

volunteer.html   259) 

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