tor-webwml.git

1) ## translation metadata

2) # Revision: $Revision$

3) # Translation-Priority: 4-optional
4) 
5) #include "head.wmi" TITLE="Tor: Volunteer" CHARSET="UTF-8"
6) <div id="content" class="clearfix">
7)   <div id="breadcrumbs">

8)     <a href="<page index>">Home &raquo; </a>

9)     <a href="<page getinvolved/volunteer>">Volunteer</a>
10)   </div>

11)   <div id="maincol">

12)     <!-- PUT CONTENT AFTER THIS TAG -->
13)     <h1>A few things everyone can do now:</h1>
14)     <ol>
15)     <li>Please consider <a href="<page docs/tor-doc-relay>">running
16)     a relay</a> to help the Tor network grow.</li>
17)     <li>Tell your friends! Get them to run relays. Get them to run hidden
18)     services. Get them to tell their friends.</li>
19)     <li>If you like Tor's goals, please <a href="<page donate/donate>">take a moment
20)     to donate to support further Tor development</a>. We're also looking
21)     for more sponsors &mdash; if you know any companies, NGOs, agencies,
22)     or other organizations that want anonymity / privacy / communications
23)     security, let them know about us.</li>
24)     <li>We're looking for more <a href="<page about/torusers>">good examples of Tor
25)     users and Tor use cases</a>. If you use Tor for a scenario or purpose not
26)     yet described on that page, and you're comfortable sharing it with us,
27)     we'd love to hear from you.</li>
28)     </ol>

29) 

30)     <a id="Documentation"></a>
31)     <h2><a class="anchor" href="#Documentation">Documentation</a></h2>
32)     <ol>

33)     <li>Help translate the
34) <!-- web page and -->
35)     documentation into other

36)     languages. See the <a href="<page getinvolved/translation>">translation
37)     guidelines</a> if you want to help out. We especially need Arabic or
38)     Farsi translations, for the many Tor users in censored areas.</li>
39)     <li>Evaluate and document

40)     <a href="<wiki>doc/TorifyHOWTO">our

41)     list of programs</a> that can be configured to use Tor.</li>
42)     <li>We have a huge list of <a

43)     href="<wiki>doc/SupportPrograms">potentially useful

44)     programs that interface with Tor</a>. Which ones are useful in which

45)     situations? Please help us test them out and document your results.</li>
46)     </ol>

47) 

48)     <a id="Advocacy"></a>
49)     <h2><a class="anchor" href="#Advocacy">Advocacy</a></h2>
50)     <ol>

51)     <li>Monitor some of our <a 
52)     href="https://lists.torproject.org/cgi-bin/mailman/listinfo">public mailing 
53)     lists</a>, like <a 
54)     href="https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-talk">tor-talk</a>, <a 
55)     href="https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays">tor-relays</a>, <a 
56)     href="https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-dev">tor-dev</a>, or <a 
57)     href="https://lists.torproject.org/cgi-bin/mailman/listinfo/tbb-dev">tbb-dev</a>, 
58)     and summarize noteworthy exchanges into articles for <a 

59)     href="https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-news">Tor 

60)     Weekly News</a>.</li>

61)     <li>Create a presentation that can be used for various user group
62) meetings around the world.</li>

63)     <li>Create a video about the positive uses of Tor, what Tor is,
64)     or how to use it.  Some have already started on <a

65)     href="https://media.torproject.org/video/">Tor's Media server</a>,

66)     <a

67)     href="http://www.howcast.com/videos/90601-How-To-Circumvent-an-Internet-Proxy">Howcast</a>,

68)     and <a href="http://www.youtube.com/thetorproject">YouTube</a>.</li>

69)     <li>Create a poster around a theme, such as "Tor for Freedom!"</li>

70)     <li>Create a t-shirt design that incorporates "<a
71)     href="https://check.torproject.org/">Congratulations! You are using
72)     Tor!</a>" in any language.</li>

73)     <li>Spread the word about Tor at a symposium or conference and use these
74)     <a href="https://media.torproject.org/misc/2015-03-tor-brochure/">Tor
75)     brochures</a> in PDF and ODG format and translated to at least ten
76)     different languages as conversation starter.</li>

77)     </ol>

78) 

79) <!--

80)     <a id="gsoc"></a>
81)     <h2><a class="anchor" href="#gsoc">Google Summer of Code</a></h2>
82) 
83)     <p>
84)     Tor is also taking part in this year's <a
85)     href="https://www.google-melange.com/gsoc/homepage/google/gsoc2013">Google
86)     Summer of Code</a>! The criteria for this is a little different - either
87)     gender can apply but you need to be either <a
88)     href="https://www.google-melange.com/gsoc/document/show/gsoc_program/google/gsoc2013/help_page#2._Whos_eligible_to_participate_as_a">a
89)     present student or just graduated</a>.
90)     </p>
91) 
92)     <p>
93)     As mentioned above if you're eligible for either program then please apply
94)     for both! Google Summer of Code is a far, far larger program for us than
95)     OPW so your chances of being applied that way are considerably better.
96)     </p>
97) 
98)     <p>
99)     <b>See our page for <a href="<page about/gsoc>">Google Summer of Code</a>
100)     for more information.</b>
101)     </p>

102) -->

103) 

104)     <a id="Projects"></a>
105)     <h2><a class="anchor" href="#Projects">Projects</a></h2>

106) 

107)     <p>
108)     Below are a list of Tor related projects we're developing and/or
109)     maintaining. Most discussions happen on IRC so if you're interested in any
110)     of these (or you have a project idea of your own), then please <a

111)     href="<page about/contact>#irc">join us in #tor-dev</a>. Don't be shy
112)     to ask questions, and don't hesitate to ask even if the main contributors
113)     aren't active at that moment.

114)     </p>

115) 

116)     <p>
117)     For a presentation summarizing many of these projects see...
118)     </p>
119) 
120)     <div id="ecosystem_presentation">

121)       <a href="https://www.youtube.com/watch?v=fb6iqZcQsSg">Tor Ecosystem</a> (<a href="https://media.torproject.org/video/2013-11-t3am-damian-johnson.mp4">mp4</a>, <a href="https://svn.torproject.org/svn/projects/presentations/2013-11-t3am-tor-ecosystem.pdf">slides</a>)

122)     </div>
123) 
124)     <br /></br />
125) 

126)     <table id="projects">
127)       <tr>
128)         <th>Name</th>
129)         <th>Category</th>
130)         <th>Language</th>
131)         <th>Activity</th>
132)         <th>Contributors</th>
133)       </tr>

134) 

135)       <tr>
136)         <td><a href="#project-tor">Tor</a></td>
137)         <td>Core</td>
138)         <td>C</td>
139)         <td>Heavy</td>

140)         <td>nickm, athena, arma</td>

141)       </tr>

142) 

143)       <tr>

144)         <td><a href="#project-torbrowser">Tor Browser</a></td>

145)         <td>Bundle</td>

146)         <td>Javascript, XUL, Scripting</td>

147)         <td>Heavy</td>

148)         <td>mikeperry, Pearl Crescent</td>

149)       </tr>
150) 

151)       <tr>

152)         <td><a href="#project-httpseverywhere">HTTPS Everywhere</a></td>
153)         <td>Browser Add-on</td>
154)         <td>Javascript</td>

155)         <td>Heavy</td>

156)         <td>pde, mikeperry</td>

157)       </tr>

158) 

159)       <tr>

160)         <td><a href="#project-nyx">Nyx</a></td>

161)         <td>User Interface</td>
162)         <td>Python, Curses</td>

163)         <td>Heavy</td>

164)         <td>atagar</td>
165)       </tr>

166) 

167)       <tr>

168)         <td><a href="#project-orbot">Orbot</a></td>
169)         <td>User Interface</td>
170)         <td>Java</td>

171)         <td>Moderage</td>

172)         <td>n8fr8</td>

173)       </tr>

174) 

175)       <tr>

176)         <td><a href="#project-tails">Tails</a></td>
177)         <td>OS image</td>
178)         <td>Sys Admin</td>
179)         <td>Heavy</td>
180)         <td><a href="https://tails.boum.org/">#tails</a></td>

181)       </tr>

182) 

183)       <tr>

184)         <td><a href="#project-torramdisk">tor-ramdisk</a></td>
185)         <td>OS image</td>
186)         <td>Sys Admin</td>

187)         <td>Light</td>

188)         <td>blueness</td>
189)       </tr>
190) 

191)       <tr>

192)         <td><a href="#project-torsocks">Torsocks</a></td>
193)         <td>Usability</td>
194)         <td>C</td>

195)         <td>Light</td>

196)         <td>David Goulet</td>

197)       </tr>
198) 

199)       <tr>

200)         <td><a href="#project-torbirdy">TorBirdy</a></td>
201)         <td>Browser Add-on</td>
202)         <td>JavaScript</td>

203)         <td>Light</td>
204)         <td>sukhe</td>

205)       </tr>

206) 

207)       <tr>

208)         <td><a href="#project-obfsproxy">Obfsproxy</a></td>
209)         <td>Client Add-on</td>

210)         <td>Python</td>

211)         <td>None</td>

212)         <td>asn</td>

213)       </tr>
214) 

215)       <tr>

216)         <td><a href="#project-flash-proxy">Flash Proxy</a></td>
217)         <td>Client Add-on</td>
218)         <td>Python, JavaScript, Go</td>

219)         <td>Light</td>

220)         <td>dcf, infinity0, Arlo Breault</td>

221)       </tr>

222) 

223)       <tr>

224)         <td><a href="#project-shadow">Shadow</a></td>

225)         <td>Simulator</td>

226)         <td>C, Python</td>

227)         <td>Heavy</td>

228)         <td>robgjansen</td>
229)       </tr>

230) 

231)       <tr>
232)         <td><a href="#project-chutney">Chutney</a></td>
233)         <td>Simulator</td>
234)         <td>Python</td>
235)         <td>Light</td>
236)         <td>nickm</td>
237)       </tr>
238) 

239)       <tr>

240)         <td><a href="#project-stem">Stem</a></td>

241)         <td>Library</td>
242)         <td>Python</td>

243)         <td>Heavy</td>

244)         <td>atagar</td>

245)       </tr>

246) 

247)       <tr>

248)         <td><a href="#project-txtorcon">Txtorcon</a></td>
249)         <td>Library</td>
250)         <td>Python, Twisted</td>

251)         <td>Light</td>

252)         <td>meejah</td>
253)       </tr>

254) 

255)       <tr>

256)         <td><a href="#project-tlsdate">Tlsdate</a></td>
257)         <td>Utility</td>
258)         <td>C</td>

259)         <td>None</td>

260)         <td>ioerror</td>
261)       </tr>

262) 

263)       <tr>

264)         <td><a href="#project-metrics">Metrics</a></td>
265)         <td>Client Service</td>
266)         <td>Java</td>

267)         <td>Moderate</td>

268)         <td>karsten</td>
269)       </tr>

270) 

271)       <tr>

272)         <td><a href="#project-atlas">Atlas</a></td>
273)         <td>Client Service</td>
274)         <td>JavaScript</td>

275)         <td>None</td>

276)         <td></td>

277)       </tr>

278) 

279)       <tr>
280)         <td><a href="#project-globe">Globe</a></td>
281)         <td>Client Service</td>
282)         <td>JavaScript</td>

283)         <td>None</td>
284)         <td></td>

285)       </tr>
286) 

287)       <tr>

288)         <td><a href="#project-compass">Compass</a></td>
289)         <td>Client Service</td>
290)         <td>Python</td>

291)         <td>None</td>
292)         <td></td>

293)       </tr>

294) 

295)       <tr>

296)         <td><a href="#project-onionoo">Onionoo</a></td>
297)         <td>Backend Service</td>

298)         <td>Java</td>

299)         <td>Light</td>

300)         <td>karsten</td>

301)       </tr>
302) 

303)       <tr>
304)         <td><a href="#project-exitmap">ExitMap</a></td>
305)         <td>Backend Service</td>
306)         <td>Python</td>

307)         <td>Light</td>

308)         <td>phw</td>
309)       </tr>
310) 

311)       <tr>
312)         <td><a href="#project-doctor">DocTor</a></td>
313)         <td>Backend Service</td>
314)         <td>Python</td>

315)         <td>Light</td>

316)         <td>atagar</td>
317)       </tr>
318) 

319)       <tr>

320)         <td><a href="#project-weather">Weather</a></td>
321)         <td>Client Service</td>
322)         <td>Python</td>

323)         <td>None</td>

324)         <td>kaner</td>
325)       </tr>

326) 

327)       <tr>

328)         <td><a href="#project-gettor">GetTor</a></td>
329)         <td>Client Service</td>
330)         <td>Python</td>

331)         <td>Light</td>
332)         <td>ilv</td>

333)       </tr>

334) 

335)       <tr>

336)         <td><a href="#project-torcheck">TorCheck</a></td>
337)         <td>Client Service</td>

338)         <td>Go</td>

339)         <td>None</td>

340)         <td>Arlo</td>

341)       </tr>

342) 

343)       <tr>

344)         <td><a href="#project-bridgedb">BridgeDB</a></td>
345)         <td>Backend Service</td>
346)         <td>Python</td>

347)         <td>Light</td>

348)         <td>isis</td>

349)       </tr>

350) 

351)       <tr>

352)         <td><a href="#project-ooni-probe">Ooni Probe</a></td>

353)         <td>Scanner</td>
354)         <td>Python</td>

355)         <td>Moderate</td>

356)         <td>hellais, aagbsn</td>

357)       </tr>
358) 

359)       <tr>
360)         <td><a href="#project-torps">TorPS</a></td>
361)         <td>Backend Service</td>
362)         <td>Python</td>

363)         <td>None</td>

364)         <td>Aaron Johnson</td>
365)       </tr>
366) 

367)       <tr>

368)         <td><a href="#project-torflow">TorFlow</a></td>
369)         <td>Backend Service</td>
370)         <td>Python</td>

371)         <td>None</td>

372)         <td>aagbsn</td>

373)       </tr>

374) 

375)       <tr>

376)         <td><a href="#project-tor2web">Tor2web</a></td>
377)         <td>Client Service</td>

378)         <td>Python</td>

379)         <td>Heavy</td>

380)         <td>evilaliv3, hellais</td>

381)       </tr>

382) 

383)       <tr>

384)         <td><a href="#project-anonbib">Anonbib</a></td>
385)         <td>Website</td>

386)         <td>Python</td>

387)         <td>Light</td>

388)         <td>arma, nickm</td>
389)       </tr>

390)     </table>

391) 

392)     <sub>
393)     * Project is still in an alpha state.
394)     </sub>

395) 

396)     <br /><br />

397) 

398)     <a id="project-tor"></a>
399)     <h3>Tor (<a href="https://gitweb.torproject.org/tor.git">code</a>, <a

400)     href="https://trac.torproject.org/projects/tor/report/12">bug

401)     tracker</a>)</h3>

402) 

403)     <p>
404)     Central project, providing the core software for using and participating in
405)     the Tor network. Numerous people contribute to the project to varying
406)     extents, but the chief architects are Nick Mathewson and Roger Dingledine.
407)     </p>

408) 

409)     <p>
410)     <b>Project Ideas:</b><br />

411)     <i><a href="#torCleanup">Tor Codebase Cleanup</a></i><br />

412)     <i><a href="#improveTorTestCoverage">Improve test coverage in Tor</a></i><br />
413)     <i><a href="#useMoreCores">Have the Tor daemon use more cores</a></i><br />
414)     <i><a href="#improveHiddenServices">Help improve Tor hidden services</a></i><br />

415)     <i><a href="#improvedDnsSupport">Improved DNS support for Tor</a></i>

416)     </p>

417) 

418)     <a id="project-torbrowser"></a>

419)     <h3><a href="<page projects/torbrowser>">Tor Browser</a> (<a

420)     href="https://gitweb.torproject.org/tor-browser.git">code</a>, <a

421)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torbutton&component=Tor+Launcher&component=Tor+Browser&component=Tor+bundles%2Finstallation&col=id&col=summary&col=status&col=owner&col=type&col=priority&col=milestone&order=priority">bug

422)     tracker</a>, <a href="https://www.torproject.org/projects/torbrowser/design/">design doc</a>)</h3>
423) 

424)     <p>

425)     Tor Browser is an easy-to-use, portable package of Tor, HTTPS-Everywhere, 
426)     NoScript, TorLauncher, Torbutton, and a Firefox fork, all  preconfigured 
427)     to work together out of
428)     the box. The modified copy of Firefox aims to resolve the

429)     privacy and security issues in mainline version.

430)     </p>

431) 
432)     <a id="project-httpseverywhere"></a>
433)     <h3><a href="https://www.eff.org/https-everywhere">HTTPS Everywhere</a> (<a
434)     href="https://gitweb.torproject.org/https-everywhere.git">code</a>, <a
435)     href="https://trac.torproject.org/projects/tor/report/19">bug

436)     tracker</a>)</h3>

437) 

438)     <p>

439)     HTTPS Everywhere is a Firefox and Chrome extension that encrypts
440)     your communications with many major websites, making your browsing
441)     more secure.

442)     </p>

443) 

444)     <a id="project-nyx"></a>
445)     <h3><a href="https://www.atagar.com/arm/">Nyx</a> (<a
446)     href="https://gitweb.torproject.org/nyx.git">code</a>, <a

447)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=arm&order=priority">bug
448)     tracker</a>)</h3>

449) 

450)     <p>

451)     Nyx (previously <i>arm</i>) is a terminal status monitor for Tor

452)     intended for command-line aficionados, ssh connections, and anyone with a
453)     tty terminal. This works much like top does for system usage, providing
454)     real time statistics for bandwidth, resource usage, connections, and quite
455)     a bit more.

456)     </p>

457) 

458)     <a id="project-orbot"></a>
459)     <h3><a href="https://guardianproject.info/apps/orbot/">Orbot</a> (<a

460)     href="https://gitweb.torproject.org/orbot.git">code</a>, <a

461)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Orbot&order=priority">bug
462)     tracker</a>)</h3>

463) 
464)     <p>

465)     Provides Tor on the Android platform. The project is under active 
466)     development, updates to latest Tor releases, and working to stay up to 
467)     date with all changes in Android and mobile threats.

468)     </p>
469) 
470)     <a id="project-tails"></a>
471)     <h3><a href="https://tails.boum.org/">The Amnesic Incognito Live System</a> (<a

472)     href="https://git-tails.immerda.ch/tails/">code</a>, <a
473)     href="https://labs.riseup.net/code/projects/tails">bug

474)     tracker</a>, <a href="https://tails.boum.org/doc">documentation</a>, <a
475)     href="https://tails.boum.org/contribute/design/">design</a>, <a
476)     href="https://tails.boum.org/contribute">contribute</a>)</h3>

477) 
478)     <p>
479)     The Amnesic Incognito Live System is a live CD/USB distribution
480)     preconfigured so that everything is safely routed through Tor and leaves no
481)     trace on the local system. This is a merger of the Amnesia and <a
482)     href="http://www.anonymityanywhere.com/incognito/">Incognito</a> projects,
483)     and still under very active development.
484)     </p>
485) 

486)     <a id="project-torramdisk"></a>
487)     <h3><a href="http://opensource.dyc.edu/tor-ramdisk">Tor-ramdisk</a> (<a

488)     href="https://gitweb.torproject.org/tor-ramdisk.git">code</a>, <a

489)     href="http://opensource.dyc.edu/tor-ramdisk-documentation">documentation</a>)</h3>

490) 
491)     <p>

492)     Tor-ramdisk is a uClibc-based micro Linux distribution whose sole
493)     purpose is to securely host a Tor server purely in RAM.

494)     </p>
495) 

496)     <a id="project-torsocks"></a>

497)     <h3>Torsocks (<a

498)     href="https://gitweb.torproject.org/torsocks.git">code</a>, <a
499)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torify&order=priority">bug
500)     tracker</a>)</h3>
501) 

502)     <p>

503)     Utility for adapting other applications to work with Tor. Development has
504)     slowed and compatibility issues remain with some platforms, but it's
505)     otherwise feature complete.

506)     </p>

507) 

508)     <a id="project-torbirdy"></a>
509)     <h3>TorBirdy (<a
510)     href="https://github.com/ioerror/torbirdy">code</a>, <a
511)     href="https://trac.torproject.org/projects/tor/wiki/torbirdy/dev">bug
512)     tracker</a>)</h3>

513) 

514)     <p>
515)     TorBirdy is Torbutton for Thunderbird and related Mozilla mail clients.
516)     </p>

517) 

518)     <p>
519)     <b>Project Ideas:</b><br />
520)     <i><a href="#makeTorbirdyBetter">Make TorBirdy Better</a></i>
521)     </p>
522) 

523)     <a id="project-obfsproxy"></a>

524)     <h3><a href="<page projects/obfsproxy>">Obfsproxy</a> (<a

525)     href="https://gitweb.torproject.org/pluggable-transports/obfsproxy.git">code</a>,
526)     <a href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Pluggable+transport&order=priority">bug

527)     tracker</a>)</h3>

528) 

529)     <p>
530)     A proxy that shapes Tor traffic, making it harder for censors to detect and

531)     block Tor. This has both a C and python implementation.

532)     </p>

533) 

534)     <p>
535)     <b>Project Ideas:</b><br />

536)     <i><a href="https://trac.torproject.org/projects/tor/wiki/doc/PluggableTransports#Helpneeded">Various coding tasks</a></i> <br/>

537)     <i><a href="#betterPluggableTransports">Build Better Pluggable Transports</a></i>
538)     </p>
539) 

540)     <a id="project-flash-proxy"></a>
541)     <h3><a href="https://crypto.stanford.edu/flashproxy/">Flash Proxy</a> (<a
542)     href="https://gitweb.torproject.org/flashproxy.git">code</a>, <a
543)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_information&status=needs_review&status=needs_revision&status=new&status=reopened&component=Flashproxy">bug
544)     tracker</a>)</h3>

545) 

546)     <p>
547)     Pluggable transport using proxies running in web browsers to defeat
548)     address-based blocking.
549)     </p>

550) 

551)     <a id="project-chutney"></a>
552)     <h3>Chutney (<a href="https://gitweb.torproject.org/chutney.git">code</a>,
553)     <a href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_information&status=needs_review&status=needs_revision&status=new&status=reopened&component=Chutney">bug
554)     tracker</a>)</h3>
555) 
556)     <p>
557)     Integration test suite that spawns a local tor network, checking the
558)     interactions of its components.
559)     </p>
560) 

561)     <a id="project-shadow"></a>
562)     <h3><a href="https://shadow.cs.umn.edu/">Shadow</a> (<a
563)     href="https://github.com/shadow">code</a>, <a
564)     href="https://github.com/shadow/shadow/issues">bug
565)     tracker</a>)</h3>

566) 

567)     <p>
568)     Shadow is a discrete-event network simulator that runs the real
569)     Tor software as a plug-in. Shadow is open-source software that enables
570)     accurate, efficient, controlled, and repeatable Tor experimentation.

571)     For another simulator, see <a
572)     href="http://crysp.uwaterloo.ca/software/exptor/">ExperimenTor</a>.

573)     </p>

574) 

575)     <a id="project-stem"></a>

576)     <h3><a href="https://stem.torproject.org/">Stem</a> (<a

577)     href="https://gitweb.torproject.org/stem.git">code</a>, <a

578)     href="https://trac.torproject.org/projects/tor/wiki/doc/stem/bugs">bug

579)     tracker</a>)</h3>

580) 

581)     <p>

582)     Python controller library for scripts and controller applications using
583)     Tor.

584)     </p>

585) 

586)     <p>
587)     <b>Project Ideas:</b><br />

588)     <i><a href="#txtorcon-stemIntegration">Txtorcon/Stem Integration</a></i><br />

589)     </p>

590) 

591)     <a id="project-txtorcon"></a>

592)     <h3><a href="https://txtorcon.readthedocs.org">Txtorcon</a> (<a

593)     href="https://github.com/meejah/txtorcon">code</a>, <a

594)     href="https://github.com/meejah/txtorcon/issues">bug tracker</a>)</h3>

595) 

596)     <p>
597)     Twisted-based asynchronous Tor control protocol implementation. Includes
598)     unit-tests, examples, state-tracking code and configuration abstraction.
599)     Used by OONI and APAF.
600)     </p>

601) 

602)     <p>
603)     <b>Project Ideas:</b><br />
604)     <i><a href="#txtorcon-stemIntegration">Txtorcon/Stem Integration</a></i>
605)     </p>
606) 

607)     <a id="project-tlsdate"></a>
608)     <h3>Tlsdate (<a href="https://github.com/ioerror/tlsdate">code</a>)</h3>

609) 

610)     <p>
611)     tlsdate: secure parasitic rdate replacement
612)     </p>

613) 

614)     <p>
615)     tlsdate sets the local clock by securely connecting with TLS to remote
616)     servers and extracting the remote time out of the secure handshake. Unlike
617)     ntpdate, tlsdate uses TCP, for instance connecting to a remote HTTPS or TLS
618)     enabled service, and provides some protection against adversaries that try
619)     to feed you malicious time information.
620)     </p>

621) 

622)     <a id="project-metrics"></a>
623)     <h3><a href="https://metrics.torproject.org/">Metrics</a> (code: <a
624)     href="https://gitweb.torproject.org/metrics-db.git">db</a>, <a

625)     href="https://gitweb.torproject.org/metrics-web.git">web</a>)</h3>

626) 

627)     <p>
628)     Processing and analytics of consensus data, provided to users via the
629)     metrics portal. This has been under active development for several years by

630)     Karsten Loesing. See also <a
631)     href="https://gitweb.torproject.org/torperf.git">TorPerf</a>.

632)     </p>

633) 

634)     <a id="project-atlas"></a>
635)     <h3><a href="https://atlas.torproject.org/">Atlas</a> (<a
636)     href="https://gitweb.torproject.org/atlas.git">code</a>)</h3>

637) 

638)     <p>
639)     Atlas is a web application to discover Tor relays and bridges. It provides
640)     useful information on how relays are configured along with graphics about

641)     their past usage.

642)     </p>

643) 

644)     <p>

645)     This is the spiritual successor to <a
646)     href="https://gitweb.torproject.org/torstatus.git">TorStatus</a>, the <a

647)     href="https://svn.torproject.org/svn/torstatus/trunk/">original

648)     codebase</a> for which was written in PHP, and rewritten by students from
649)     Wesleyan as Django.

650)     </p>

651) 

652)     <a id="project-globe"></a>
653)     <h3><a href="http://globe.rndm.de/">Globe</a> (<a
654)     href="https://github.com/makepanic/globe">code</a>, <a
655)     href="https://github.com/makepanic/globe/issues">bug tracker</a>)</h3>
656) 
657)     <p>
658)     Globe is a web application that allows you to search for Tor relays and
659)     bridges. It gives you a detailed overview of properties and configurations
660)     of a relay or bridge.
661)     </p>
662) 

663)     <a id="project-compass"></a>
664)     <h3><a href="https://compass.torproject.org/">Compass</a> (<a
665)     href="https://gitweb.torproject.org/compass.git">code</a>, <a
666)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Compass&order=priority">bug
667)     tracker</a>)</h3>

668) 

669)     <p>
670)     Compass is a web and command line application that filters and
671)     aggregates the Tor relays based on various attributes.
672)     </p>

673) 
674)     <a id="project-onionoo"></a>

675)     <h3><a href="https://onionoo.torproject.org/">Onionoo</a> (<a
676)     href="https://gitweb.torproject.org/onionoo.git">code</a>,
677)     <a href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Onionoo&order=priority">bug tracker</a>)</h3>

678) 
679)     <p>
680)     Onionoo is a JSON based protocol to learn information about currently
681)     running Tor relays and bridges.
682)     </p>
683) 

684)     <a id="project-exitmap"></a>
685)     <h3><a href="http://www.cs.kau.se/philwint/spoiled_onions/">ExitMap</a> (<a
686)     href="https://github.com/NullHypothesis/exitmap">code</a>, <a
687)     href="https://github.com/NullHypothesis/exitmap/issues">bug tracker</a>)</h3>
688) 
689)     <p>

690)     Scanner for the Tor network by Philipp Winter to detect malicious and
691)     misconfigured exits. For more information about how it works see his <a
692)     href="http://www.cs.kau.se/philwint/spoiled_onions/pets2014.pdf">Spoiled

693)     Onions</a> research paper.
694)     </p>
695) 

696)     <p>
697)     <b>Project Ideas:</b><br />
698)     <i><a href="#exitmap_improvements">Exitmap Improvements</a></i>
699)     </p>
700) 

701)     <a id="project-doctor"></a>
702)     <h3>DocTor (<a
703)     href="https://gitweb.torproject.org/doctor.git">code</a>, <a
704)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=DocTor&order=priority">bug
705)     tracker</a>)</h3>
706) 
707)     <p>
708)     DocTor is a notification service that monitors newly published descriptor
709)     information for issues. This is primarily a service to help the tor
710)     directory authority operators, but it also checks for a handful of other
711)     issues like sybil attacks.
712)     </p>
713) 

714)     <a id="project-weather"></a>

715)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/org/roadmaps/Weather">Weather</a> (<a

716)     href="https://gitweb.torproject.org/weather.git">code</a>, <a
717)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Tor+Weather&order=priority">bug
718)     tracker</a>)</h3>

719) 

720)     <p>
721)     Provides automatic notification to subscribed relay operators when their
722)     relay's unreachable. This underwent a rewrite by the <a
723)     href="http://hfoss.wesleyan.edu/">Wesleyan HFOSS team</a>, which went live
724)     in early 2011.
725)     </p>

726) 

727)     <a id="project-gettor"></a>

728)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/org/roadmaps/GetTor">GetTor</a> (<a

729)     href="https://gitweb.torproject.org/gettor.git">code</a>, <a

730)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=GetTor&order=priority">bug
731)     tracker</a>)</h3>

732) 

733)     <p>
734)     E-mail autoresponder providing Tor's packages over SMTP. This has been
735)     relatively unchanged for quite a while.
736)     </p>

737) 

738)     <a id="project-torcheck"></a>

739)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/org/roadmaps/TorCheck">TorCheck</a> (<a

740)     href="https://gitweb.torproject.org/check.git">code</a>, <a

741)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Tor+Check&order=priority">bug
742)     tracker</a>)</h3>

743) 

744)     <p>

745)     Site for determining if the visitor is using Tor or not.

746)     </p>

747) 

748)     <a id="project-bridgedb"></a>

749)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/org/roadmaps/BridgeDB">BridgeDB</a> (<a

750)     href="https://gitweb.torproject.org/bridgedb.git">code</a>, <a
751)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=BridgeDB&order=priority">bug
752)     tracker</a>)</h3>

753) 

754)     <p>
755)     Backend bridge distributor, handling the various pools they're distributed
756)     in. This was actively developed until Fall of 2010.
757)     </p>

758) 
759)     <a id="project-ooni-probe"></a>

760)     <h3><a href="https://ooni.torproject.org/">Ooni Probe</a> (<a

761)     href="https://gitweb.torproject.org/ooni-probe.git">code</a>, <a
762)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Ooni&order=priority">bug
763)     tracker</a>)</h3>
764) 
765)     <p>
766)     Censorship scanner, checking your local connection for blocked or modified
767)     content.
768)     </p>
769) 

770)     <p>
771)     <b>Project Ideas:</b><br />

772)     <i><a href="#ooniprobePcapsSupport">Add Support for Reporting Pcaps to OoniBackend and OoniProbe</a></i>

773)     </p>
774) 

775)     <a id="project-torps"></a>
776)     <h3>TorPS</a> (<a href="https://github.com/torps/torps">code</a>)</h3>
777) 
778)     <p>
779)     The Tor Path Simulator (TorPS) is a tool for efficiently simulating
780)     path selection in Tor. It chooses circuits and assigns user streams to
781)     those circuits in the same way that Tor does. TorPS is fast enough to
782)     perform thousands of simulations over periods of months.
783)     </p>
784) 

785)     <a id="project-torflow"></a>

786)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/org/roadmaps/TorFlow">TorFlow</a> (<a

787)     href="https://gitweb.torproject.org/torflow.git">code</a>, <a
788)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torflow&order=priority">bug
789)     tracker</a>)</h3>

790) 

791)     <p>
792)     Library and collection of services for actively monitoring the Tor network.
793)     These include the Bandwidth Scanners (measuring throughput of relays) and
794)     SoaT (scans for malicious or misconfigured exit nodes). SoaT was last
795)     actively developed in the Summer of 2010, and the Bandwidth Scanners a few
796)     months later. Both have been under active use since then, but development
797)     has stopped.
798)     </p>

799) 
800)     <a id="project-tor2web"></a>
801)     <h3><a
802)     href="http://wiki.tor2web.org/index.php/Main_Page">Tor2web</a> (<a
803)     href="https://github.com/globaleaks/tor2web-3.0/wiki">code</a>)</h3>
804) 
805)     <p>
806)     Tor2web allows Internet users to browse websites running in <a
807)     href="<page docs/hidden-services>">Tor hidden services</a>. It trades
808)     user anonymity for usability by allowing anonymous content to be
809)     distributed to non-anonymous users.
810)     </p>
811) 

812)     <a id="project-anonbib"></a>
813)     <h3><a
814)     href="http://freehaven.net/anonbib/">Anonymity Bibliography</a> (<a
815)     href="https://gitweb.torproject.org/anonbib.git">code</a>)</h3>
816) 
817)     <p>

818)     Anonbib is a list of important papers in the field of anonymity. It's
819)     also a set of scripts to generate the website from Latex (bibtex). If
820)     we're missing any important papers, please let us know!

821)     </p>
822) 

823)     <a id="Coding"></a>
824)     <a id="Summer"></a>

825)     <h2><a class="anchor" href="#Coding">Project Ideas</a></h2>

826) 

827)     <p>

828)     You may find some of these projects to be good ideas for <a href="<page
829)     about/gsoc>">Google Summer of Code</a> and the <a
830)     href="https://live.gnome.org/OutreachProgramForWomen">Outreach Program for

831)     Women</a>. We have labelled each idea with how much work we expect it would
832)     be (effort level), how much clue you should start with (skill level),
833)     and which of our <a href="<page about/corepeople>">core developers</a>
834)     would be good mentors. If one or more of these ideas looks promising to
835)     you, please <a href="<page about/contact>">contact us</a> to discuss your
836)     plans rather than sending blind applications. You may also want to propose
837)     your own project idea &mdash; which often results in the best applications.

838)     </p>

839) 

840)     <ol>

841) 

842)     <a id="txtorcon-stemIntegration"></a>
843)     <li>
844)     <b>Txtorcon/Stem Integration</b>
845)     <br>
846)     Effort Level: <i>Medium</i>
847)     <br>
848)     Skill Level: <i>Medium</i>
849)     <br>
850)     Likely Mentors: <i>meejah, Damian (atagar)</i>
851)     <p>Txtorcon is a Twisted-based Python controller library, and Stem is a
852)     synchronous (threaded) one, also in Python. There is no need to have
853)     two implementations of (at least) the protocol parsing code. This
854)     project would entail eliminating duplication by leveraging Stem's
855)     parsing in txtorcon while keeping txtorcon's API the same (or at least
856)     close).</p>

857)     <p>Besides this you should identify some additional tasks to improve our
858)     controller space across these two libraries. Some ideas are...</p>
859)     <ul>
860)       <li>Write a tutorial for <a
861)       href="https://stem.torproject.org/tutorials.html">stem's tutorial
862)       page</a> demonstrating cross txtorcon/stem usage.</li>
863)       <li>Expand the txtorcon API to include functionality of <a

864)       href="https://gitweb.torproject.org/stem.git/tree/stem/control.py">stem's

865)       controller</a> that would be of interest to twisted users. All additions
866)       should include tests!</li>
867)       <li>Come up with some ideas of your own! We'd love to discuss them with
868)       you.</li>
869)     </ul>

870)     <p>This would very likely involve changes to both libraries, although
871)     most would be expected to be in txtorcon. meejah is available to
872)     mentor txtorcon changes, and Damian (atagar) can help with Stem.</p>
873)     <p>It would help if you're already familiar with event-based programming,
874)     bonus points if it's Twisted.</p>
875)     </li>
876) 

877)     <a id="torCleanup"></a>

878)     <li>

879)     <b>Tor Codebase Cleanup</b>

880)     <br>

881)     Effort Level: <i>Low to High, depending on subproject chosen</i>

882)     <br>

883)     Skill Level: <i>Medium to High</i>

884)     <br>

885)     Likely Mentors: <i>Nick (nickm), David (dgoulet)</i>

886)     <p>

887)     The Tor code is more than 10 years old in places, and we haven't always had

888)     enough time or wisdom to write things as well as we could have.  Our unit
889)     test coverage is shamefully low, and the dependency graph of our modules is
890)     shamefully convoluted . We could use refactoring and unit tests!  Please
891)     look through the Tor source code and look for ugly or tricky code or
892)     dependencies -- the uglier and trickier the better -- and think about how
893)     you could make the code look better, read better, and (subject to testing)
894)     work better.

895)     </p>

896) 

897)     <p>

898)     If this is for a fun side-project, it would be great for you to work on
899)     anything that can be made better and more tested.  For an internship-level
900)     position, we'd hope that you could find a number of particularly tricky or
901)     knotty piece of the code to clean up, and aim for resolving the ugliest
902)     problems, not necessarily the easiest.

903)     </p>

904) 

905)     <p>

906)     For a big project here, it would be great to pick one of the major
907)     "submodules" of Tor -- path selection, node discovery, directory authority
908)     operations, directory service -- and refactor its interface completely, to
909)     minify and codify its points of contact with the rest of Tor.

910)     </p>

911) 
912)     <p>
913)     <b>As part of your application for this project please identify one of the
914)     thorniest Tor functions and submit a patch refactoring it to be better. If
915)     you find this to be difficult then this likely isn't the project for
916)     you.</b>
917)     </p>

918)     </li>

919) 

920)     <a id="betterPluggableTransports"></a>
921)     <li>
922)     <b>Build Better Pluggable Transports</b>
923)     <br>
924)     Effort Level: <i>Medium to High</i>
925)     <br>
926)     Skill Level: <i>Medium</i>
927)     <br>

928)     Likely Mentors: <i>Ximin (infinity0)</i>

929)     <p>

930)     For Tor users in censored countries, we have a <a

931)     href="<page docs/pluggable-transports>">

932)     pluggable transports</a> framework that uses external programs to bypass
933)     censorship in different ways. Each of these have their own strengths and
934)     weaknesses.

935)     </p>
936) 
937)     <p>

938)     We have deployed <a

939)     href="<page projects/obfsproxy>">obfsproxy</a>, 
940)     <a href="http://crypto.stanford.edu/flashproxy/">flashproxy</a>, 
941)     <a href="http://www.cs.kau.se/philwint/scramblesuit/">scramblesuit</a>, 
942)     <a href="https://trac.torproject.org/projects/tor/wiki/doc/meek">meek</a>,
943)     and <a href="https://fteproxy.org/about">FTE</a> bridges into the main 
944)     Tor Browser.</a>

945)     </p>
946) 
947)     <p>
948)     There are several possible directions for this project. Ideas include:
949)       <ol>
950)         <li>Address gaps or weaknesses in our existing pluggable transports
951)           <ul>
952)             <li>Flashproxy: Add WebRTC support to traverse NATs.</li>
953)             <li>Flashproxy: Improve the facilitator's resistance against DoS
954)             and poisoning attacks.</li>
955)           </ul>
956)         </li>

957)         <li>Finish and release our pluggable transport combiner, that chains
958)         several transports together to take advantage of orthogonal types of
959)         blocking resistance.</li>

960)         <li>Improve the UX for selecting the appropriate pluggable transport in

961)         the new Tor Browser, whilst maintaining user security.</li>

962)         <li>Implement a new pluggable transport that resists blocking in a
963)         novel way.
964)         <ul>
965)           <li>Impersonate a voice-over-IP protocol</li>
966)           <li>Impersonate HTTP <a
967)           href="http://www.cs.utexas.edu/~amir/papers/parrot.pdf">sufficiently
968)           well</a> that traffic will go through a HTTP-only proxy</li>
969)           <li>Implement <a
970)           href="http://cacr.uwaterloo.ca/techreports/2011/cacr2011-21.pdf">scanning
971)           resistance</a></li>
972)         </ul>
973)         </li>
974)       </ol>
975)     </p>
976) 
977)     <p>
978)     Applicants should be familiar with asynchronous/reactive programming, in
979)     particular the <a href="https://twistedmatrix.com/">Twisted framework</a>
980)     or something related. Most of the existing code is written in Python, with
981)     some parts in JavaScript and Go, so you should know at least one of these.
982)     You are invited to talk to us and ask questions, via our mailing lists
983)     or IRC. <b>As part of your application, please contribute a patch that
984)     implements a small feature or fixes a bug related to this area, e.g. <a
985)     href="https://trac.torproject.org/projects/tor/query?status=!closed&component=Pluggable+transport">1</a>,
986)     <a href="https://trac.torproject.org/projects/tor/query?status=!closed&component=Obfsproxy">2</a>,
987)     <a href="https://trac.torproject.org/projects/tor/query?status=!closed&component=Flashproxy">3</a>.
988)     </b>

989)     </p>
990) 
991)     <a id="profileUDPTransport"></a>
992)     <li>
993)     <b>Profile UDP transport protocols</b>
994)     <br>
995)     Effort Level: <i>Medium to High</i>
996)     <br>
997)     Skill Level: <i>High</i>
998)     <br>

999)     Likely Mentors: <i>Yawning</i>

1000)     <p>
1001)     There are <a
1002)     href="https://research.torproject.org/techreports/datagram-comparison-2011-11-07.pdf">lots
1003)     of options</a> as to how Tor could send its data over UDP rather than TCP,
1004)     and some will likely perform significantly better than others. This project
1005)     will evaluate these options, so as to decide which should be used in future
1006)     versions of Tor. A first step will be to benchmark the various transport
1007)     protocols being considered, in terms of performance and also code quality,
1008)     including userspace TCP, <a
1009)     href="https://github.com/bittorrent/libutp">&mu;TP</a>, <a
1010)     href="http://en.wikipedia.org/wiki/Stream_Control_Transmission_Protocol">SCTP</a>
1011)     and <a href="http://curvecp.org/">CurveCP</a>. Initially these transport
1012)     protocols will be examined in isolation, but if the project progresses well
1013)     one or more could be integrated in Tor.
1014)     </p>
1015)     </li>
1016) 

1017)     <a id="makeTorbirdyBetter"></a>
1018)     <li>
1019)     <b>Make TorBirdy Better</b>
1020)     <br>
1021)     Effort Level: <i>High</i>
1022)     <br>
1023)     Skill Level: <i>Medium</i>
1024)     <br>
1025)     Likely Mentors: <i>Sukhbir Singh (sukhe), Jacob Appelbaum (ioerror)</i>
1026)     <p>
1027) TorBirdy is an extension that configures Thunderbird to make connections over
1028) the Tor anonymity network. TorBirdy has been under development for quite a
1029) while but there are two known leaks that prevent it from being used by a wider

1030) audience. As part of this project, you will be working on implementing a HTTP
1031) proxy.

1032)     </p>
1033) 
1034)     <p>
1035) 
1036)     <p>

1037) <b>HTTP Proxy</b> TorBirdy needs a HTTP proxy or a HTTP -&gt; SOCKS5 shim. Please look at

1038) ticket <a href="https://trac.torproject.org/projects/tor/ticket/6958">#6958</a>

1039) for more information. Note: this has to be done using JavaScript and without using

1040) an external proxy.
1041)     </p>
1042) 
1043)     <p>
1044) If time permits and you are awesome enough to finish the above two tasks, you

1045) will be working on the <a href="https://trac.torproject.org/projects/tor/query?status=!closed&component=TorBirdy">
1046) remaining TorBirdy tickets</a>.

1047)     </p>
1048) 
1049)     <p>

1050) Applicants should be familiar with JavaScript (and preferably C++ as well). As
1051) part of your application for this project, please submit code samples for
1052) previous JavaScript projects that you have developed, or point us to projects
1053) you have been involved with (links to a public Git/GitHub repository
1054) preferred).  Prior extension development is a big plus and will be given
1055) preference during application ranking.

1056)     </p>
1057) 
1058)     <p>

1059) You may contact the mentors on IRC for more information. (sukhe on #tor-dev, #tor on irc.oftc.net)

1060)     </p>
1061)     </li>
1062) 

1063)     <a id="ooniprobePcapsSupport"></a>
1064)     <li>
1065)     <b>Add Support for Reporting Pcaps to OoniBackend and OoniProbe</b>
1066)     <br>
1067)     Effort Level: <i>Medium</i>
1068)     <br>
1069)     Skill Level: <i>Medium</i>
1070)     <br>

1071)     Likely Mentors: <i>Arturo (hellais)</i>

1072)     <p>
1073) The feature should also add support for including only packet capture data that
1074) is relevant to the test being run. This means that the pcap should not contain
1075) all the data sniffed on the users machine, but only that which was generated
1076) and intended to be received by ooniprobe.
1077)     </p>
1078) 
1079)     <p>
1080) This can probably be implemented by setting up a tun/tap device and routing all
1081) the ooniprobe traffic through it and only capturing data sent and received from
1082) that device. The task for the student will also be that of doing research into
1083) what are possible strategies for doing this. <b><a
1084) href="https://trac.torproject.org/projects/tor/ticket/7416">For more
1085) information see ticket 7416.</a></b>
1086)     </p>
1087)     </li>
1088) 

1089)     <a id="improveTorTestCoverage"></a>
1090)     <li>
1091)     <b>Improve test coverage in Tor</b>
1092)     <br>
1093)     Effort Level: <i>Medium</i>
1094)     <br>
1095)     Skill Level: <i>Medium</i>
1096)     <br>

1097)     Likely Mentors: <i>Nick (nickm), David (dgoulet)</i>

1098)     <p>
1099) Right now, our unit test coverage with the tests we ship is around 30%
1100) -- only 30% of the executable lines in our source are reached by the
1101) unit tests.  Improving this test coverage could make Tor development
1102) much more reliable.
1103)     </p>
1104) 
1105)     <p>
1106) So we need better unit tests, and we need better integration tests too.
1107)     </p>
1108) 
1109)     <p>

1110) Improving unit tests would involve refactoring functions to be more

1111) testable, and writing a bunch of unit tests.
1112)     </p>
1113) 
1114)     <p>

1115) Improving integration tests would involve refactoring and improving

1116) the "chutney" program that launches a test tor network, and writing a
1117) bunch of tests to see what works and what doesn't work on such a
1118) network.  It could also involve writing tests using the library "<a
1119) href="https://stem.torproject.org/">stem</a>" to script individual clients on a
1120) Chutney network.
1121)     </p>
1122) 
1123)     <p>
1124) To get a feel for how testing works in Tor today, download Tor and
1125) Chutney, and make sure you can build Tor and use Chutney.  See how the
1126) unit tests work by skimming some of the test code in the src/test
1127) subdirectory.  Try computing test coverage (according to the
1128) instructions in the doc/HACKING file.
1129)     </p>
1130) 
1131)     <p>
1132) Also, have a look at the one current integration test that works on
1133) chutney today: it is a shell script distributed with Tor as
1134) src/test/test-tor-network.sh .  We probably don't want to have all of
1135) our integration tests be written as shell scripts, but it's interesting
1136) to see how one works.
1137)     </p>
1138) 
1139)     <p>
1140) If working on designs for an improved or refactored Chutney, watch out for <a
1141) href="http://www.joelonsoftware.com/articles/fog0000000018.html">"archicture
1142) astronautics"</a>: while it's important that we have a well-designed and
1143) maintainable Chutney architecture, it wouldn't be very useful if a good
1144) architecture were the <em>only</em> outcome here: we need tests too.
1145)     </p>
1146) 
1147)     <p>
1148) As part of the application process, please contribute a patch that makes
1149) a non-trivial improvement to chutney, and/or include a new test for some
1150) interesting Tor function. (Please pick a function that isn't completely
1151) easy to test.)
1152)     </p>
1153)     </li>
1154) 
1155)     <a id="useMoreCores"></a>
1156)     <li>
1157)     <b>Have the Tor daemon use more cores</b>
1158)     <br>
1159)     Effort Level: <i>Medium</i>
1160)     <br>
1161)     Skill Level: <i>Medium</i>
1162)     <br>

1163)     Likely Mentors: <i>Nick (nickm), David (dgoulet)</i>

1164)     <p>
1165) Right now, if you run a busy Tor server on a multicore computer, most of
1166) the cores are mostly unused.  We have a "cpuworker" mechanism to move
1167) expensive computations into worker threads, but that mechanism is
1168) currently only used for a small fraction of our cryptography.  Moving
1169) more work into the worker threads could improve performance immensely.
1170)     </p>
1171) 
1172)     <p>
1173) So it would be great to parallelize our cryptography more in order to
1174) better handle more cores.  See
1175) <a href="https://trac.torproject.org/projects/tor/wiki/org/projects/Tor/MultithreadedCrypto">MultithreadedCrypto</a>
1176) for some background info, and
1177) <a href="https://trac.torproject.org/projects/tor/ticket/7572">ticket 7572</a> for some subtickets
1178) on our tracker.
1179)     </p>
1180) 
1181)     <p>
1182) (If you're reading through the code to see how it works today, you will
1183) also want to have a look at the new implementation for cpuworkers
1184) described in <a href="https://trac.torproject.org/projects/tor/ticket/9682">9682</a>.)
1185)     </p>
1186) 
1187)     <p>
1188) Completing the implementation of ticket #7572 --which would move our
1189) circuit crypto onto separate threads-- could be a good summer project.
1190) Alternatively, moving all of the signature generation and verification
1191) code onto the cpuworkers could be fun.  In either case, you will have
1192) some important architectural decisions to make about how to minimize
1193) shared data between the main thread and the workers, how to avoid
1194) race conditions between them, and how to test it all to make sure it has
1195) no hidden failure cases.
1196)     </p>
1197) 
1198)     <p>
1199) As part of the application process for this project, please contribute a
1200) nontrivial patch to Tor -- ideally, one that will affect some part of
1201) the codebase that you want to work on.
1202)     </p>
1203)     </li>
1204) 
1205)     <a id="improveHiddenServices"></a>
1206)     <li>
1207)     <b>Help improve Tor hidden services</b>
1208)     <br>
1209)     Effort Level: <i>Medium</i>
1210)     <br>
1211)     Skill Level: <i>Medium</i>
1212)     <br>

1213)     Likely Mentors: <i>Nick (nickm), David (dgoulet), George (asn)</i>

1214)     <p>
1215) We're working on a revamp of the entire Tor hidden service design to
1216) improve the security and reliability of the hidden service system.
1217)     </p>
1218) 
1219)     <p>
1220) This is a big project: see

1221) <a href="https://gitweb.torproject.org/torspec.git/tree/proposals/224-rend-spec-ng.txt">proposal

1222) 224</a> for the latest design.  Are you interested in implementing some
1223) part of that?
1224)     </p>
1225) 
1226)     <p>
1227) This is a very ambitious project, so we're deliberately not suggesting
1228) particular sub-topics.  If you're interested in participating, try to
1229) read and understand the <a

1230) href="https://gitweb.torproject.org/torspec.git/tree/rend-spec.txt">existing

1231) design</a> and the design proposal for the new design, and then talk to
1232) us about what part you want to work on.
1233)     </p>
1234) 
1235)     <p>
1236) As part of the application process for this project, please contribute a
1237) nontrivial patch to Tor -- ideally, one that will affect some part of
1238) the codebase that you want to work on.
1239)     </p>
1240)     </li>
1241) 
1242)     <a id="improvedDnsSupport"></a>
1243)     <li>
1244)     <b>Improved DNS support for Tor</b>
1245)     <br>
1246)     Effort Level: <i>Medium</i>
1247)     <br>
1248)     Skill Level: <i>Medium</i>
1249)     <br>

1250)     Likely Mentors: <i>Nick (nickm), David (dgoulet)</i>

1251)     <p>
1252) Right now, you can only use Tor's DNS support to look up IPv4 and IPv6
1253) addresses, and to fetch PTR records.  But DNS can do so much more!
1254)     </p>
1255) 
1256)     <p>
1257) <a

1258) href="https://gitweb.torproject.org/torspec.git/tree/proposals/219-expanded-dns.txt">Proposal

1259) 219</a> describes some new cell types that Tor could use to support
1260) more types of DNS over Tor.
1261)     </p>
1262) 
1263)     <p>
1264) To see how Tor implements its existing DNS lookups, start by tracing the
1265) the connection_exit_begin_resolve() function in src/or/connection_edge.c ,
1266) and see how we pass these requests downwards through src/or/dns.c to the
1267) underlying resolver.  It's not too complicated, but there are some
1268) tricky parts to understand.
1269)     </p>
1270) 
1271)     <p>
1272) As part of the application process for this project, please contribute a
1273) nontrivial patch to Tor -- ideally, one that will affect some part of
1274) the codebase that you want to work on.
1275)     </p>
1276)     </li>
1277) 

1278)     <a id="ahmiaSearch"></a>
1279)     <li>
1280)     <b>Ahmia - Hidden Service Search</b>
1281)     <br>
1282)     Effort Level: <i>Medium</i>
1283)     <br>
1284)     Skill Level: <i>Medium</i>
1285)     <br>
1286)     Likely Mentors: <i>Juha Nurmi (numes), George (asn)</i>
1287)     <p>
1288) Ahmia is open-source search engine software for Tor hidden service deep dark web sites. You can test the running search engine at ahmia.fi. For more information see our <a href="https://blog.torproject.org/category/tags/ahmiafi">blog post about Ahmia's GSoC2014 development</a>.
1289)     </p>
1290) 
1291)     <p>
1292) Ahmia is a working search engine that indexes, searches, and catalogs content published on Tor Hidden Services. Furthermore, it is an environment to share meaningful insights, statistics, insights, and news about the Tor network itself. In this context, there is a lot of work to do.
1293)     </p>
1294) 
1295)     <p>
1296) The Ahmia web service is written using the Django web framework. As a result, the server-side language is Python. On the client-side, most of the pages are plain HTML. There are some pages that require JavaScript, but the search itself works without client-side JavaScript.
1297)     </p>
1298) 
1299)     <p>
1300) There are several possible directions for this project, including...
1301)     </p>
1302) 
1303)     <ol>
1304)       <li>Improving the search results (very important)<br />
1305)         <ul>
1306)           <li>Tweaking search algorithms</li>
1307)           <li>Adjust Apache Solr</li>
1308)           <li>Enrich the data that is used to rank the search results</li>
1309)         </ul>
1310)       </li>
1311)       <li>Improving UX and UI (very important)<br />
1312)         <ul>
1313)           <li>Showing relevant knowledge</li>
1314)           <li>Design the navigation and information architecture</li>
1315)           <li>HTML5, CSS and Django development</li>
1316)         </ul>
1317)       </li>
1318)       <li>Review code and infrastructure<br />
1319)         <ul>
1320)           <li>Review code and fix bugs</li>
1321)           <li>Writing Django test cases</li>
1322)           <li>Linux configurations, automatizations</li>
1323)         </ul>
1324)       </li>
1325)       <li>Gather statistics over time and publish them<br />
1326)         <ul>
1327)           <li>Gather different kind of stats about Hidden Services</li>
1328)           <li>Publish these stats using HTTP REST API</li>
1329)           <li>Using this API show meaningful tables, charts and visualizations</li>
1330)         </ul>
1331)       </li>
1332)     </ol>
1333)     </p>
1334)     </li>

1335) 
1336)     <a id="exitmap_improvements"></a>
1337)     <li>
1338)     <b>Exitmap Improvements</b>
1339)     <br>
1340)     Effort Level: <i>Medium</i>
1341)     <br>
1342)     Skill Level: <i>Medium</i>
1343)     <br>
1344)     Likely Mentors: <i>Philipp (phw)</i>
1345)     <p>
1346) The Tor Project makes use of the Python tool <a
1347) href="https://gitweb.torproject.org/user/phw/exitmap.git/">Exitmap</a> to
1348) systematically scan for malicious and misbehaving exit relays.  Once such a
1349) relay is found, it is assigned the BadExit flag which prevents clients from
1350) selecting the relay as last hop in their circuit.
1351)     </p>
1352) 
1353)     <p>
1354) Exitmap supports scanning modules which implement a specific scan over
1355) exit relays.  Examples are the DNS module which checks for DNS poisoning
1356) or the patching check module which looks out for tampered file
1357) downloads.
1358)     </p>
1359) 
1360)     <p>
1361) This project is meant to extend exitmap in several ways.  First, it
1362) should be made fully autonomous.  That means that exitmap should be able
1363) to run in the background, periodically fetch new relay descriptors, and
1364) have a smart algorithm which keeps scanning all exit relays
1365) periodically.  Second, exitmap should be able to emulate some user
1366) interaction and dynamically "explore" the web in order to detect
1367) tampering.  Third, unit tests should be added for existing and new code
1368) in order to make the code base more robust.
1369)     </p>
1370)     </li>

1371) 
1372)     <a id="coniks_in_messenger"></a>
1373)     <li>
1374)     <b>Implement and Integrate CONIKS for Tor Messenger</b>
1375)     <br>
1376)     Effort Level: <i>Medium</i>
1377)     <br>
1378)     Skill Level: <i>Medium</i>
1379)     <br>
1380)     Likely Mentors: <i>Marcela, Arlo (arlolra)</i>
1381)     <p>
1382) CONIKS is an end-user key management and verification system for end-to-end
1383) secure communication services, which improves upon existing key management
1384) systems by providing both strong security and better usability using a model
1385) called key transparency. CONIKS does this by requiring providers to manage
1386) tamper-evident, publicly-auditable key directories, which contain mappings from
1387) usernames to public keys, on behalf of their users. This design makes it easier
1388) for users (both "default" users and power users) to establish trust since they
1389) don't have to worry about or even see keys, but users also don't have to
1390) trust the provider to be well-behaved because the CONIKS client can run as
1391) part of the secure messaging app and automatically check that the service
1392) provider doesn’t map spurious keys to their users' usernames, and it can
1393) verify that observed name-to-key mappings are consistent with what other
1394) clients in the system are seeing. Unlike existing key transparency solutions,
1395) CONIKS also provides strong privacy guarantees by employing cryptographic
1396) primitives for robust data obfuscation.
1397)     </p>
1398) 
1399)     <p>
1400) The CONIKS system design, protocols, and proof-of-concept are described in
1401) great detail in the <a
1402) href="https://www.usenix.org/system/files/conference/usenixsecurity15/sec15-paper-melara.pdf">CONIKS
1403) research paper</a>, and basic reference implementations of a CONIKS key server
1404) and a CONIKS client are avialable on <a
1405) href="https://github.com/coniks-sys/coniks-ref-implementation">Github</a>.
1406)     </p>
1407) 
1408)     <p>
1409) This project has two main components: (1) designing and implementing a CONIKS
1410) key server tailored to Tor Messenger users, and (2) building a CONIKS client
1411) which integrates with the Tor Messenger client. One challenge the applicant
1412) will face is ensuring that the key server design is efficient and scalable for
1413) large volumes of users, concurrent traffic and guarantees this scalability even
1414) as Tor Messenger's user base grows. On the client side, the main challenges
1415) will be to focus on space efficiency as well as minimizing computational
1416) overhead when implementing the CONIKS consistency checks, and determining how
1417) to best communicate CONIKS consistency check results to users in the UI. Since
1418) Tor Messenger does not hand out online identities per se, as most online
1419) communication services do (like, say, Twitter, in which each user has a unique
1420) handle), the CONIKS key server for Tor Messenger will have to map usernames
1421) from third-party communication services to the encryption keys used in Tor
1422) Messenger. One additional important challenge that the applicant will have to
1423) help address is ensuring that each such third-party username remains unique in
1424) the Tor Messenger space and that such external, third-party identities are
1425) indeed controlled by the expected user of that third-party communication
1426) service.
1427)     </p>
1428) 
1429)     <p>
1430) Some design and implementation questions have been discussed in <a
1431) href="https://trac.torproject.org/projects/tor/ticket/17961">Ticket #17961</a>.
1432)     </p>
1433) 
1434)     <p>
1435) The applicant should have some familiarity with well-known crypto primitives
1436) and algorithms, as well as have a basic understanding of the key transparency
1437) model. Client side integration will require some basic use of JavaScript.
1438) Consider submitting a patch for <a
1439) href="https://github.com/arlolra/ctypes-otr/issues">one of the open key
1440) verification issues</a> as part of the application process.
1441)     </p>
1442)     </li>

1443) <!--
1444)     <a id=""></a>
1445)     <li>
1446)     <b></b>
1447)     <br>
1448)     Effort Level: <i>Medium</i>
1449)     <br>
1450)     Skill Level: <i>Medium</i>
1451)     <br>
1452)     Likely Mentors: <i>Damian (atagar)</i>
1453)     <p>
1454) 
1455)     </p>
1456) 
1457)     <p>
1458) 
1459)     </p>
1460)     </li>
1461) -->
1462) 

1463)     <li>
1464)     <b>Bring up new ideas!</b>

1465)     <br>

1466)     Don't like any of these? Look at the <a

1467)     href="/press/presskit/2008-12-19-roadmap-full.pdf">Tor development

1468)     roadmap</a> for more ideas, or just try out Tor and Tor Browser,

1469)     and find out what you think needs fixing.

1470)     Some of the <a href="<spectree>proposals">current proposals</a>

1471)     might also be short on developers.
1472)     </li>

1473) 

1474)     </ol>

1475) 

1476)     <a id="OtherCoding"></a>
1477)     <h2><a class="anchor" href="#OtherCoding">Other Coding and Design related ideas</a></h2>
1478)     <ol>
1479)     <li>Tor relays don't work well on Windows XP. On
1480)     Windows, Tor uses the standard <tt>select()</tt> system
1481)     call, which uses space in the non-page pool. This means
1482)     that a medium sized Tor relay will empty the non-page pool, <a

1483)     href="<wiki>doc/WindowsBufferProblems">causing

1484)     havoc and system crashes</a>. We should probably be using overlapped IO
1485)     instead. One solution would be to teach <a
1486)     href="http://www.monkey.org/~provos/libevent/">libevent</a> how to use
1487)     overlapped IO rather than select() on Windows, and then adapt Tor to
1488)     the new libevent interface. Christian King made a
1489)     <a href="https://svn.torproject.org/svn/libevent-urz/trunk/">good
1490)     start</a> on this in the summer of 2007.</li>

1491) 

1492)     <li>We need a flexible simulator framework for studying end-to-end
1493)     traffic confirmation attacks. Many researchers have whipped up ad hoc
1494)     simulators to support their intuition either that the attacks work
1495)     really well or that some defense works great. Can we build a simulator
1496)     that's clearly documented and open enough that everybody knows it's
1497)     giving a reasonable answer? This will spur a lot of new research.
1498)     See the entry <a href="#Research">below</a> on confirmation attacks for
1499)     details on the research side of this task &mdash; who knows, when it's
1500)     done maybe you can help write a paper or three also.</li>

1501) 

1502)     <li>Tor 0.1.1.x and later include support for hardware crypto
1503)     accelerators via OpenSSL. It has been lightly tested and is
1504)     possibly very buggy.  We're looking for more rigorous testing,

1505)     performance analysis, and optimally, code fixes to OpenSSL and

1506)     Tor if needed.</li>

1507) 

1508)     <li>Write a <a
1509)     href="https://secure.wikimedia.org/wikipedia/en/wiki/Fuzz_testing">fuzzer</a>
1510)     for Tor to discover security vulnerabilities. Determine if there
1511)     are good fuzzing frameworks out there for what we want. Win fame by

1512)     getting credit when we put out a new release because of you!</li>

1513) 

1514)     <li>Tor uses TCP for transport and TLS for link
1515)     encryption. This is nice and simple, but it means all cells
1516)     on a link are delayed when a single packet gets dropped, and
1517)     it means we can only reasonably support TCP streams. We have a <a

1518)     href="<page docs/faq>#TransportIPnotTCP">list

1519)     of reasons why we haven't shifted to UDP transport</a>, but it would
1520)     be great to see that list get shorter. We also have a proposed <a

1521)     href="<specblob>proposals/100-tor-spec-udp.txt">specification

1522)     for Tor and
1523)     UDP</a> &mdash; please let us know what's wrong with it.</li>

1524) 

1525)     <li>We're not that far from having IPv6 support for destination addresses
1526)     (at exit nodes). If you care strongly about IPv6, that's probably the
1527)     first place to start.</li>

1528) 

1529)     <li>We need a way to generate the website diagrams (for example, the "How
1530)     Tor Works" pictures on the <a href="<page about/overview>">overview page</a>
1531)     from source, so we can translate them as UTF-8 text rather than edit
1532)     them by hand with Gimp. We might want to
1533)     integrate this as an wml file so translations are easy and images are
1534)     generated in multiple languages whenever we build the website.</li>

1535) 

1536)     <li>How can we make the various LiveCD/USB systems easier
1537)     to maintain, improve, and document?  One example is <a

1538)     href="https://tails.boum.org/">The Amnesic Incognito Live

1539)     System</a>.
1540)     </li>

1541) 

1542)     <li>
1543)     Another anti-censorship project is to try to make Tor
1544)     more scanning-resistant.  Right now, an adversary can identify <a

1545)     href="<specblob>proposals/125-bridges.txt">Tor bridges</a>

1546)     just by trying to connect to them, following the Tor protocol,
1547)     and seeing if they respond.  To solve this, bridges could <a
1548)     href="<svnprojects>design-paper/blocking.html#tth_sEc9.3">act like
1549)     webservers</a> (HTTP or HTTPS) when contacted by port-scanning tools,
1550)     and not act like bridges until the user provides a bridge-specific key.
1551)     To start, check out Shane Pope's <a
1552)     href="http://dl.dropbox.com/u/37735/index.html">thesis and prototype</a>.
1553)     </li>

1554) 

1555)     </ol>

1556) 

1557)     <a id="Research"></a>
1558)     <h2><a class="anchor" href="#Research">Research</a></h2>
1559)     <ol>
1560)     <li>The "end-to-end traffic confirmation attack":
1561)     by watching traffic at Alice and at Bob, we can <a
1562)     href="http://freehaven.net/anonbib/#danezis:pet2004">compare
1563)     traffic signatures and become convinced that we're watching the same
1564)     stream</a>. So far Tor accepts this as a fact of life and assumes this
1565)     attack is trivial in all cases. First of all, is that actually true? How
1566)     much traffic of what sort of distribution is needed before the adversary
1567)     is confident he has won? Are there scenarios (e.g. not transmitting much)
1568)     that slow down the attack? Do some traffic padding or traffic shaping
1569)     schemes work better than others?</li>
1570)     <li>A related question is: Does running a relay/bridge provide additional
1571)     protection against these timing attacks? Can an external adversary that can't
1572)     see inside TLS links still recognize individual streams reliably?
1573)     Does the amount of traffic carried degrade this ability any? What if the
1574)     client-relay deliberately delayed upstream relayed traffic to create a queue
1575)     that could be used to mimic timings of client downstream traffic to make it
1576)     look like it was also relayed? This same queue could also be used for masking
1577)     timings in client upstream traffic with the techniques from <a
1578)     href="http://www.freehaven.net/anonbib/#ShWa-Timing06">adaptive padding</a>,
1579)     but without the need for additional traffic. Would such an interleaving of
1580)     client upstream traffic obscure timings for external adversaries? Would the
1581)     strategies need to be adjusted for asymmetric links? For example, on
1582)     asymmetric links, is it actually possible to differentiate client traffic from
1583)     natural bursts due to their asymmetric capacity? Or is it easier than
1584)     symmetric links for some other reason?</li>
1585)     <li>Repeat Murdoch and Danezis's <a
1586)     href="http://www.cl.cam.ac.uk/~sjm217/projects/anon/#torta">attack from
1587)     Oakland 05</a> on the current Tor network. See if you can learn why it
1588)     works well on some nodes and not well on others. (My theory is that the
1589)     fast nodes with spare capacity resist the attack better.) If that's true,
1590)     then experiment with the RelayBandwidthRate and RelayBandwidthBurst
1591)     options to run a relay that is used as a client while relaying the
1592)     attacker's traffic: as we crank down the RelayBandwidthRate, does the
1593)     attack get harder? What's the right ratio of RelayBandwidthRate to
1594)     actually capacity? Or is it a ratio at all? While we're at it, does a
1595)     much larger set of candidate relays increase the false positive rate
1596)     or other complexity for the attack? (The Tor network is now almost two
1597)     orders of magnitude larger than it was when they wrote their paper.) Be
1598)     sure to read <a href="http://freehaven.net/anonbib/#clog-the-queue">Don't
1599)     Clog the Queue</a> too.</li>
1600)     <li>The "routing zones attack": most of the literature thinks of
1601)     the network path between Alice and her entry node (and between the
1602)     exit node and Bob) as a single link on some graph. In practice,
1603)     though, the path traverses many autonomous systems (ASes), and <a
1604)     href="http://freehaven.net/anonbib/#feamster:wpes2004">it's not uncommon
1605)     that the same AS appears on both the entry path and the exit path</a>.
1606)     Unfortunately, to accurately predict whether a given Alice, entry,
1607)     exit, Bob quad will be dangerous, we need to download an entire Internet
1608)     routing zone and perform expensive operations on it. Are there practical
1609)     approximations, such as avoiding IP addresses in the same /8 network?</li>
1610)     <li>Other research questions regarding geographic diversity consider
1611)     the tradeoff between choosing an efficient circuit and choosing a random
1612)     circuit. Look at Stephen Rollyson's <a
1613)     href="http://swiki.cc.gatech.edu:8080/ugResearch/uploads/7/ImprovingTor.pdf">position
1614)     paper</a> on how to discard particularly slow choices without hurting
1615)     anonymity "too much". This line of reasoning needs more work and more
1616)     thinking, but it looks very promising.</li>
1617)     <li>Tor doesn't work very well when relays have asymmetric bandwidth
1618)     (e.g. cable or DSL). Because Tor has separate TCP connections between
1619)     each hop, if the incoming bytes are arriving just fine and the outgoing
1620)     bytes are all getting dropped on the floor, the TCP push-back mechanisms
1621)     don't really transmit this information back to the incoming streams.
1622)     Perhaps Tor should detect when it's dropping a lot of outgoing packets,
1623)     and rate-limit incoming streams to regulate this itself? I can imagine
1624)     a build-up and drop-off scheme where we pick a conservative rate-limit,
1625)     slowly increase it until we get lost packets, back off, repeat. We
1626)     need somebody who's good with networks to simulate this and help design
1627)     solutions; and/or we need to understand the extent of the performance
1628)     degradation, and use this as motivation to reconsider UDP transport.</li>
1629)     <li>A related topic is congestion control. Is our
1630)     current design sufficient once we have heavy use? Maybe
1631)     we should experiment with variable-sized windows rather
1632)     than fixed-size windows? That seemed to go well in an <a

1633)     href="http://www.psc.edu/index.php/hpn-ssh/638">ssh

1634)     throughput experiment</a>. We'll need to measure and tweak, and maybe
1635)     overhaul if the results are good.</li>
1636)     <li>Our censorship-resistance goals include preventing
1637)     an attacker who's looking at Tor traffic on the wire from <a
1638)     href="<svnprojects>design-paper/blocking.html#sec:network-fingerprint">distinguishing
1639)     it from normal SSL traffic</a>. Obviously we can't achieve perfect
1640)     steganography and still remain usable, but for a first step we'd like to
1641)     block any attacks that can win by observing only a few packets. One of
1642)     the remaining attacks we haven't examined much is that Tor cells are 512
1643)     bytes, so the traffic on the wire may well be a multiple of 512 bytes.
1644)     How much does the batching and overhead in TLS records blur this on the
1645)     wire? Do different buffer flushing strategies in Tor affect this? Could
1646)     a bit of padding help a lot, or is this an attack we must accept?</li>
1647)     <li>Tor circuits are built one hop at a time, so in theory we have the
1648)     ability to make some streams exit from the second hop, some from the
1649)     third, and so on. This seems nice because it breaks up the set of exiting
1650)     streams that a given relay can see. But if we want each stream to be safe,
1651)     the "shortest" path should be at least 3 hops long by our current logic, so
1652)     the rest will be even longer. We need to examine this performance / security
1653)     tradeoff.</li>
1654)     <li>It's not that hard to DoS Tor relays or directory authorities. Are client
1655)     puzzles the right answer? What other practical approaches are there? Bonus
1656)     if they're backward-compatible with the current Tor protocol.</li>
1657)     <li>Programs like <a

1658)     href="<page docs/torbutton/index>">Torbutton</a> aim to hide

1659)     your browser's UserAgent string by replacing it with a uniform answer for
1660)     every Tor user. That way the attacker can't splinter Tor's anonymity set
1661)     by looking at that header. It tries to pick a string that is commonly used
1662)     by non-Tor users too, so it doesn't stand out. Question one: how badly
1663)     do we hurt ourselves by periodically updating the version of Firefox
1664)     that Torbutton claims to be? If we update it too often, we splinter the
1665)     anonymity sets ourselves. If we don't update it often enough, then all the
1666)     Tor users stand out because they claim to be running a quite old version
1667)     of Firefox. The answer here probably depends on the Firefox versions seen
1668)     in the wild. Question two: periodically people ask us to cycle through N
1669)     UserAgent strings rather than stick with one. Does this approach help,
1670)     hurt, or not matter? Consider: cookies and recognizing Torbutton users
1671)     by their rotating UserAgents; malicious websites who only attack certain
1672)     browsers; and whether the answers to question one impact this answer.
1673)     </li>
1674)     <li>How many bridge relays do you need to know to maintain
1675)     reachability? We should measure the churn in our bridges. If there is
1676)     lots of churn, are there ways to keep bridge users more likely to stay
1677)     connected?
1678)     </li>
1679)     </ol>

1680) 

1681)     <p>
1682)     <a href="<page about/contact>">Let us know</a> if you've made progress on any
1683)     of these!
1684)     </p>
1685)   </div>
1686)   <!-- END MAINCOL -->
1687)   <div id = "sidecol">
1688) #include "side.wmi"
1689) #include "info.wmi"
1690)   </div>
1691)   <!-- END SIDECOL -->
1692) </div>
1693) <!-- END CONTENT -->