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-tormessenger">Tor Messenger</a></td>
201)         <td>Bundle</td>
202)         <td>JavaScript, XUL, Scripting</td>
203)         <td>Heavy</td>
204)         <td>arlolra, boklm, sukhe</td>
205)       </tr>
206) 

207)       <tr>

208)         <td><a href="#project-torbirdy">TorBirdy</a></td>
209)         <td>Browser Add-on</td>
210)         <td>JavaScript</td>

211)         <td>Light</td>
212)         <td>sukhe</td>

213)       </tr>

214) 

215)       <tr>

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

218)         <td>Python</td>

219)         <td>None</td>

220)         <td>asn</td>

221)       </tr>
222) 

223)       <tr>

224)         <td><a href="#project-flash-proxy">Flash Proxy</a></td>
225)         <td>Client Add-on</td>
226)         <td>Python, JavaScript, Go</td>

227)         <td>Light</td>

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

229)       </tr>

230) 

231)       <tr>

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

233)         <td>Simulator</td>

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

235)         <td>Heavy</td>

236)         <td>robgjansen</td>
237)       </tr>

238) 

239)       <tr>
240)         <td><a href="#project-chutney">Chutney</a></td>
241)         <td>Simulator</td>
242)         <td>Python</td>
243)         <td>Light</td>
244)         <td>nickm</td>
245)       </tr>
246) 

247)       <tr>

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

249)         <td>Library</td>
250)         <td>Python</td>

251)         <td>Heavy</td>

252)         <td>atagar</td>

253)       </tr>

254) 

255)       <tr>

256)         <td><a href="#project-txtorcon">Txtorcon</a></td>
257)         <td>Library</td>
258)         <td>Python, Twisted</td>

259)         <td>Light</td>

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

262) 

263)       <tr>

264)         <td><a href="#project-tlsdate">Tlsdate</a></td>
265)         <td>Utility</td>
266)         <td>C</td>

267)         <td>None</td>

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

270) 

271)       <tr>

272)         <td><a href="#project-metrics">Metrics</a></td>
273)         <td>Client Service</td>
274)         <td>Java</td>

275)         <td>Moderate</td>

276)         <td>karsten</td>
277)       </tr>

278) 

279)       <tr>

280)         <td><a href="#project-atlas">Atlas</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-globe">Globe</a></td>
289)         <td>Client Service</td>
290)         <td>JavaScript</td>

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

293)       </tr>
294) 

295)       <tr>

296)         <td><a href="#project-compass">Compass</a></td>
297)         <td>Client Service</td>
298)         <td>Python</td>

299)         <td>None</td>
300)         <td></td>

301)       </tr>

302) 

303)       <tr>

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

306)         <td>Java</td>

307)         <td>Light</td>

308)         <td>karsten</td>

309)       </tr>
310) 

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

315)         <td>Light</td>

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

319)       <tr>
320)         <td><a href="#project-doctor">DocTor</a></td>
321)         <td>Backend Service</td>
322)         <td>Python</td>

323)         <td>Light</td>

324)         <td>atagar</td>
325)       </tr>
326) 

327)       <tr>

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

331)         <td>None</td>

332)         <td>kaner</td>
333)       </tr>

334) 

335)       <tr>

336)         <td><a href="#project-gettor">GetTor</a></td>
337)         <td>Client Service</td>
338)         <td>Python</td>

339)         <td>Light</td>
340)         <td>ilv</td>

341)       </tr>

342) 

343)       <tr>

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

346)         <td>Go</td>

347)         <td>None</td>

348)         <td>Arlo</td>

349)       </tr>

350) 

351)       <tr>

352)         <td><a href="#project-bridgedb">BridgeDB</a></td>
353)         <td>Backend Service</td>
354)         <td>Python</td>

355)         <td>Light</td>

356)         <td>isis</td>

357)       </tr>

358) 

359)       <tr>

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

361)         <td>Scanner</td>
362)         <td>Python</td>

363)         <td>Moderate</td>

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

365)       </tr>
366) 

367)       <tr>
368)         <td><a href="#project-torps">TorPS</a></td>
369)         <td>Backend Service</td>
370)         <td>Python</td>

371)         <td>None</td>

372)         <td>Aaron Johnson</td>
373)       </tr>
374) 

375)       <tr>

376)         <td><a href="#project-torflow">TorFlow</a></td>
377)         <td>Backend Service</td>
378)         <td>Python</td>

379)         <td>None</td>

380)         <td>aagbsn</td>

381)       </tr>

382) 

383)       <tr>

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

386)         <td>Python</td>

387)         <td>Heavy</td>

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

389)       </tr>

390) 

391)       <tr>

392)         <td><a href="#project-anonbib">Anonbib</a></td>
393)         <td>Website</td>

394)         <td>Python</td>

395)         <td>Light</td>

396)         <td>arma, nickm</td>
397)       </tr>

398)     </table>

399) 

400)     <sub>
401)     * Project is still in an alpha state.
402)     </sub>

403) 

404)     <br /><br />

405) 

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

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

409)     tracker</a>)</h3>

410) 

411)     <p>
412)     Central project, providing the core software for using and participating in
413)     the Tor network. Numerous people contribute to the project to varying
414)     extents, but the chief architects are Nick Mathewson and Roger Dingledine.
415)     </p>

416) 

417)     <p>
418)     <b>Project Ideas:</b><br />

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

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

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

424)     </p>

425) 

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

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

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

429)     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

430)     tracker</a>, <a href="https://www.torproject.org/projects/torbrowser/design/">design doc</a>)</h3>
431) 

432)     <p>

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

437)     privacy and security issues in mainline version.

438)     </p>

439) 
440)     <a id="project-httpseverywhere"></a>
441)     <h3><a href="https://www.eff.org/https-everywhere">HTTPS Everywhere</a> (<a
442)     href="https://gitweb.torproject.org/https-everywhere.git">code</a>, <a
443)     href="https://trac.torproject.org/projects/tor/report/19">bug

444)     tracker</a>)</h3>

445) 

446)     <p>

447)     HTTPS Everywhere is a Firefox and Chrome extension that encrypts
448)     your communications with many major websites, making your browsing
449)     more secure.

450)     </p>

451) 

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

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

457) 

458)     <p>

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

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

464)     </p>

465) 

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

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

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

471) 
472)     <p>

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

476)     </p>
477) 
478)     <a id="project-tails"></a>
479)     <h3><a href="https://tails.boum.org/">The Amnesic Incognito Live System</a> (<a

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

482)     tracker</a>, <a href="https://tails.boum.org/doc">documentation</a>, <a
483)     href="https://tails.boum.org/contribute/design/">design</a>, <a
484)     href="https://tails.boum.org/contribute">contribute</a>)</h3>

485) 
486)     <p>
487)     The Amnesic Incognito Live System is a live CD/USB distribution
488)     preconfigured so that everything is safely routed through Tor and leaves no
489)     trace on the local system. This is a merger of the Amnesia and <a
490)     href="http://www.anonymityanywhere.com/incognito/">Incognito</a> projects,
491)     and still under very active development.
492)     </p>
493) 

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

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

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

498) 
499)     <p>

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

502)     </p>
503) 

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

505)     <h3>Torsocks (<a

506)     href="https://gitweb.torproject.org/torsocks.git">code</a>, <a
507)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torify&order=priority">bug
508)     tracker</a>)</h3>
509) 

510)     <p>

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

514)     </p>

515) 

516)     <a id="project-tormessenger"></a>
517)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/doc/TorMessenger">Tor Messenger</a> (<a
518)     href="https://gitweb.torproject.org/tor-messenger-build.git">code</a>, <a
519)     href="https://trac.torproject.org/projects/tor/query?status=!closed&component=Tor+Messenger">bug tracker</a>)</h3>
520) 
521)     <p>
522)     Tor Messenger is a cross-platform chat program that aims to be secure by default and sends all of its traffic over Tor.
523)     </p>
524) 

525)     <a id="project-torbirdy"></a>
526)     <h3>TorBirdy (<a

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

528)     href="https://trac.torproject.org/projects/tor/wiki/torbirdy/dev">bug
529)     tracker</a>)</h3>

530) 

531)     <p>
532)     TorBirdy is Torbutton for Thunderbird and related Mozilla mail clients.
533)     </p>

534) 

535)     <p>
536)     <b>Project Ideas:</b><br />
537)     <i><a href="#makeTorbirdyBetter">Make TorBirdy Better</a></i>
538)     </p>
539) 

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

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

542)     href="https://gitweb.torproject.org/pluggable-transports/obfsproxy.git">code</a>,
543)     <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

544)     tracker</a>)</h3>

545) 

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

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

549)     </p>

550) 

551)     <p>
552)     <b>Project Ideas:</b><br />

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

554)     <i><a href="#betterPluggableTransports">Build Better Pluggable Transports</a></i>
555)     </p>
556) 

557)     <a id="project-flash-proxy"></a>
558)     <h3><a href="https://crypto.stanford.edu/flashproxy/">Flash Proxy</a> (<a
559)     href="https://gitweb.torproject.org/flashproxy.git">code</a>, <a
560)     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
561)     tracker</a>)</h3>

562) 

563)     <p>
564)     Pluggable transport using proxies running in web browsers to defeat
565)     address-based blocking.
566)     </p>

567) 

568)     <a id="project-chutney"></a>
569)     <h3>Chutney (<a href="https://gitweb.torproject.org/chutney.git">code</a>,
570)     <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
571)     tracker</a>)</h3>
572) 
573)     <p>
574)     Integration test suite that spawns a local tor network, checking the
575)     interactions of its components.
576)     </p>
577) 

578)     <a id="project-shadow"></a>
579)     <h3><a href="https://shadow.cs.umn.edu/">Shadow</a> (<a
580)     href="https://github.com/shadow">code</a>, <a
581)     href="https://github.com/shadow/shadow/issues">bug
582)     tracker</a>)</h3>

583) 

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

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

590)     </p>

591) 

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

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

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

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

596)     tracker</a>)</h3>

597) 

598)     <p>

599)     Python controller library for scripts and controller applications using
600)     Tor.

601)     </p>

602) 

603)     <p>
604)     <b>Project Ideas:</b><br />

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

606)     </p>

607) 

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

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

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

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

612) 

613)     <p>
614)     Twisted-based asynchronous Tor control protocol implementation. Includes
615)     unit-tests, examples, state-tracking code and configuration abstraction.
616)     Used by OONI and APAF.
617)     </p>

618) 

619)     <p>
620)     <b>Project Ideas:</b><br />
621)     <i><a href="#txtorcon-stemIntegration">Txtorcon/Stem Integration</a></i>
622)     </p>
623) 

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

626) 

627)     <p>
628)     tlsdate: secure parasitic rdate replacement
629)     </p>

630) 

631)     <p>
632)     tlsdate sets the local clock by securely connecting with TLS to remote
633)     servers and extracting the remote time out of the secure handshake. Unlike
634)     ntpdate, tlsdate uses TCP, for instance connecting to a remote HTTPS or TLS
635)     enabled service, and provides some protection against adversaries that try
636)     to feed you malicious time information.
637)     </p>

638) 

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

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

643) 

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

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

649)     </p>

650) 

651)     <a id="project-atlas"></a>
652)     <h3><a href="https://atlas.torproject.org/">Atlas</a> (<a
653)     href="https://gitweb.torproject.org/atlas.git">code</a>)</h3>

654) 

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

658)     their past usage.

659)     </p>

660) 

661)     <p>

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

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

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

667)     </p>

668) 

669)     <a id="project-globe"></a>
670)     <h3><a href="http://globe.rndm.de/">Globe</a> (<a
671)     href="https://github.com/makepanic/globe">code</a>, <a
672)     href="https://github.com/makepanic/globe/issues">bug tracker</a>)</h3>
673) 
674)     <p>
675)     Globe is a web application that allows you to search for Tor relays and
676)     bridges. It gives you a detailed overview of properties and configurations
677)     of a relay or bridge.
678)     </p>
679) 

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

685) 

686)     <p>
687)     Compass is a web and command line application that filters and
688)     aggregates the Tor relays based on various attributes.
689)     </p>

690) 
691)     <a id="project-onionoo"></a>

692)     <h3><a href="https://onionoo.torproject.org/">Onionoo</a> (<a
693)     href="https://gitweb.torproject.org/onionoo.git">code</a>,
694)     <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>

695) 
696)     <p>
697)     Onionoo is a JSON based protocol to learn information about currently
698)     running Tor relays and bridges.
699)     </p>
700) 

701)     <a id="project-exitmap"></a>
702)     <h3><a href="http://www.cs.kau.se/philwint/spoiled_onions/">ExitMap</a> (<a
703)     href="https://github.com/NullHypothesis/exitmap">code</a>, <a
704)     href="https://github.com/NullHypothesis/exitmap/issues">bug tracker</a>)</h3>
705) 
706)     <p>

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

710)     Onions</a> research paper.
711)     </p>
712) 

713)     <p>
714)     <b>Project Ideas:</b><br />
715)     <i><a href="#exitmap_improvements">Exitmap Improvements</a></i>
716)     </p>
717) 

718)     <a id="project-doctor"></a>
719)     <h3>DocTor (<a
720)     href="https://gitweb.torproject.org/doctor.git">code</a>, <a
721)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=DocTor&order=priority">bug
722)     tracker</a>)</h3>
723) 
724)     <p>
725)     DocTor is a notification service that monitors newly published descriptor
726)     information for issues. This is primarily a service to help the tor
727)     directory authority operators, but it also checks for a handful of other
728)     issues like sybil attacks.
729)     </p>
730) 

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

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

733)     href="https://gitweb.torproject.org/weather.git">code</a>, <a
734)     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
735)     tracker</a>)</h3>

736) 

737)     <p>
738)     Provides automatic notification to subscribed relay operators when their
739)     relay's unreachable. This underwent a rewrite by the <a
740)     href="http://hfoss.wesleyan.edu/">Wesleyan HFOSS team</a>, which went live
741)     in early 2011.
742)     </p>

743) 

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

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

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

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

749) 

750)     <p>
751)     E-mail autoresponder providing Tor's packages over SMTP. This has been
752)     relatively unchanged for quite a while.
753)     </p>

754) 

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

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

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

758)     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
759)     tracker</a>)</h3>

760) 

761)     <p>

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

763)     </p>

764) 

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

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

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

770) 

771)     <p>
772)     Backend bridge distributor, handling the various pools they're distributed
773)     in. This was actively developed until Fall of 2010.
774)     </p>

775) 
776)     <a id="project-ooni-probe"></a>

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

778)     href="https://gitweb.torproject.org/ooni-probe.git">code</a>, <a
779)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Ooni&order=priority">bug
780)     tracker</a>)</h3>
781) 
782)     <p>
783)     Censorship scanner, checking your local connection for blocked or modified
784)     content.
785)     </p>
786) 

787)     <p>
788)     <b>Project Ideas:</b><br />

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

790)     </p>
791) 

792)     <a id="project-torps"></a>
793)     <h3>TorPS</a> (<a href="https://github.com/torps/torps">code</a>)</h3>
794) 
795)     <p>
796)     The Tor Path Simulator (TorPS) is a tool for efficiently simulating
797)     path selection in Tor. It chooses circuits and assigns user streams to
798)     those circuits in the same way that Tor does. TorPS is fast enough to
799)     perform thousands of simulations over periods of months.
800)     </p>
801) 

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

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

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

807) 

808)     <p>
809)     Library and collection of services for actively monitoring the Tor network.
810)     These include the Bandwidth Scanners (measuring throughput of relays) and
811)     SoaT (scans for malicious or misconfigured exit nodes). SoaT was last
812)     actively developed in the Summer of 2010, and the Bandwidth Scanners a few
813)     months later. Both have been under active use since then, but development
814)     has stopped.
815)     </p>

816) 
817)     <a id="project-tor2web"></a>
818)     <h3><a
819)     href="http://wiki.tor2web.org/index.php/Main_Page">Tor2web</a> (<a
820)     href="https://github.com/globaleaks/tor2web-3.0/wiki">code</a>)</h3>
821) 
822)     <p>
823)     Tor2web allows Internet users to browse websites running in <a
824)     href="<page docs/hidden-services>">Tor hidden services</a>. It trades
825)     user anonymity for usability by allowing anonymous content to be
826)     distributed to non-anonymous users.
827)     </p>
828) 

829)     <a id="project-anonbib"></a>
830)     <h3><a
831)     href="http://freehaven.net/anonbib/">Anonymity Bibliography</a> (<a
832)     href="https://gitweb.torproject.org/anonbib.git">code</a>)</h3>
833) 
834)     <p>

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

838)     </p>
839) 

840)     <a id="Coding"></a>
841)     <a id="Summer"></a>

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

843) 

844)     <p>

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

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

855)     </p>

856) 

857)     <ol>

858) 

859)     <a id="txtorcon-stemIntegration"></a>
860)     <li>
861)     <b>Txtorcon/Stem Integration</b>
862)     <br>
863)     Effort Level: <i>Medium</i>
864)     <br>
865)     Skill Level: <i>Medium</i>
866)     <br>
867)     Likely Mentors: <i>meejah, Damian (atagar)</i>
868)     <p>Txtorcon is a Twisted-based Python controller library, and Stem is a
869)     synchronous (threaded) one, also in Python. There is no need to have
870)     two implementations of (at least) the protocol parsing code. This
871)     project would entail eliminating duplication by leveraging Stem's
872)     parsing in txtorcon while keeping txtorcon's API the same (or at least
873)     close).</p>

874)     <p>Besides this you should identify some additional tasks to improve our
875)     controller space across these two libraries. Some ideas are...</p>
876)     <ul>
877)       <li>Write a tutorial for <a
878)       href="https://stem.torproject.org/tutorials.html">stem's tutorial
879)       page</a> demonstrating cross txtorcon/stem usage.</li>
880)       <li>Expand the txtorcon API to include functionality of <a

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

882)       controller</a> that would be of interest to twisted users. All additions
883)       should include tests!</li>
884)       <li>Come up with some ideas of your own! We'd love to discuss them with
885)       you.</li>
886)     </ul>

887)     <p>This would very likely involve changes to both libraries, although
888)     most would be expected to be in txtorcon. meejah is available to
889)     mentor txtorcon changes, and Damian (atagar) can help with Stem.</p>
890)     <p>It would help if you're already familiar with event-based programming,
891)     bonus points if it's Twisted.</p>
892)     </li>
893) 

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

895)     <li>

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

897)     <br>

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

899)     <br>

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

901)     <br>

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

903)     <p>

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

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

912)     </p>

913) 

914)     <p>

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

920)     </p>

921) 

922)     <p>

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

927)     </p>

928) 
929)     <p>
930)     <b>As part of your application for this project please identify one of the
931)     thorniest Tor functions and submit a patch refactoring it to be better. If
932)     you find this to be difficult then this likely isn't the project for
933)     you.</b>
934)     </p>

935)     </li>

936) 

937)     <a id="betterPluggableTransports"></a>
938)     <li>
939)     <b>Build Better Pluggable Transports</b>
940)     <br>
941)     Effort Level: <i>Medium to High</i>
942)     <br>
943)     Skill Level: <i>Medium</i>
944)     <br>

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

946)     <p>

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

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

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

952)     </p>
953) 
954)     <p>

955)     We have deployed <a

956)     href="<page projects/obfsproxy>">obfsproxy</a>, 
957)     <a href="http://crypto.stanford.edu/flashproxy/">flashproxy</a>, 
958)     <a href="http://www.cs.kau.se/philwint/scramblesuit/">scramblesuit</a>, 
959)     <a href="https://trac.torproject.org/projects/tor/wiki/doc/meek">meek</a>,
960)     and <a href="https://fteproxy.org/about">FTE</a> bridges into the main 
961)     Tor Browser.</a>

962)     </p>
963) 
964)     <p>
965)     There are several possible directions for this project. Ideas include:
966)       <ol>
967)         <li>Address gaps or weaknesses in our existing pluggable transports
968)           <ul>
969)             <li>Flashproxy: Add WebRTC support to traverse NATs.</li>
970)             <li>Flashproxy: Improve the facilitator's resistance against DoS
971)             and poisoning attacks.</li>
972)           </ul>
973)         </li>

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

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

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

979)         <li>Implement a new pluggable transport that resists blocking in a
980)         novel way.
981)         <ul>
982)           <li>Impersonate a voice-over-IP protocol</li>
983)           <li>Impersonate HTTP <a
984)           href="http://www.cs.utexas.edu/~amir/papers/parrot.pdf">sufficiently
985)           well</a> that traffic will go through a HTTP-only proxy</li>
986)           <li>Implement <a
987)           href="http://cacr.uwaterloo.ca/techreports/2011/cacr2011-21.pdf">scanning
988)           resistance</a></li>
989)         </ul>
990)         </li>
991)       </ol>
992)     </p>
993) 
994)     <p>
995)     Applicants should be familiar with asynchronous/reactive programming, in
996)     particular the <a href="https://twistedmatrix.com/">Twisted framework</a>
997)     or something related. Most of the existing code is written in Python, with
998)     some parts in JavaScript and Go, so you should know at least one of these.
999)     You are invited to talk to us and ask questions, via our mailing lists
1000)     or IRC. <b>As part of your application, please contribute a patch that
1001)     implements a small feature or fixes a bug related to this area, e.g. <a
1002)     href="https://trac.torproject.org/projects/tor/query?status=!closed&component=Pluggable+transport">1</a>,
1003)     <a href="https://trac.torproject.org/projects/tor/query?status=!closed&component=Obfsproxy">2</a>,
1004)     <a href="https://trac.torproject.org/projects/tor/query?status=!closed&component=Flashproxy">3</a>.
1005)     </b>

1006)     </p>
1007) 
1008)     <a id="profileUDPTransport"></a>
1009)     <li>
1010)     <b>Profile UDP transport protocols</b>
1011)     <br>
1012)     Effort Level: <i>Medium to High</i>
1013)     <br>
1014)     Skill Level: <i>High</i>
1015)     <br>

1016)     Likely Mentors: <i>Yawning</i>

1017)     <p>
1018)     There are <a
1019)     href="https://research.torproject.org/techreports/datagram-comparison-2011-11-07.pdf">lots
1020)     of options</a> as to how Tor could send its data over UDP rather than TCP,
1021)     and some will likely perform significantly better than others. This project
1022)     will evaluate these options, so as to decide which should be used in future
1023)     versions of Tor. A first step will be to benchmark the various transport
1024)     protocols being considered, in terms of performance and also code quality,
1025)     including userspace TCP, <a
1026)     href="https://github.com/bittorrent/libutp">&mu;TP</a>, <a
1027)     href="http://en.wikipedia.org/wiki/Stream_Control_Transmission_Protocol">SCTP</a>
1028)     and <a href="http://curvecp.org/">CurveCP</a>. Initially these transport
1029)     protocols will be examined in isolation, but if the project progresses well
1030)     one or more could be integrated in Tor.
1031)     </p>
1032)     </li>
1033) 

1034)     <a id="makeTorbirdyBetter"></a>
1035)     <li>
1036)     <b>Make TorBirdy Better</b>
1037)     <br>
1038)     Effort Level: <i>High</i>
1039)     <br>
1040)     Skill Level: <i>Medium</i>
1041)     <br>
1042)     Likely Mentors: <i>Sukhbir Singh (sukhe), Jacob Appelbaum (ioerror)</i>
1043)     <p>
1044) TorBirdy is an extension that configures Thunderbird to make connections over
1045) the Tor anonymity network. TorBirdy has been under development for quite a
1046) while but there are two known leaks that prevent it from being used by a wider

1047) audience. As part of this project, you will be working on implementing a HTTP
1048) proxy.

1049)     </p>
1050) 
1051)     <p>
1052) 
1053)     <p>

1054) <b>HTTP Proxy</b> TorBirdy needs a HTTP proxy or a HTTP -&gt; SOCKS5 shim. Please look at

1055) ticket <a href="https://trac.torproject.org/projects/tor/ticket/6958">#6958</a>

1056) for more information. Note: this has to be done using JavaScript and without using

1057) an external proxy.
1058)     </p>
1059) 
1060)     <p>
1061) If time permits and you are awesome enough to finish the above two tasks, you

1062) will be working on the <a href="https://trac.torproject.org/projects/tor/query?status=!closed&component=TorBirdy">
1063) remaining TorBirdy tickets</a>.

1064)     </p>
1065) 
1066)     <p>

1067) Applicants should be familiar with JavaScript (and preferably C++ as well). As
1068) part of your application for this project, please submit code samples for
1069) previous JavaScript projects that you have developed, or point us to projects
1070) you have been involved with (links to a public Git/GitHub repository
1071) preferred).  Prior extension development is a big plus and will be given
1072) preference during application ranking.

1073)     </p>
1074) 
1075)     <p>

1076) You may contact the mentors on IRC for more information. (sukhe on #tor-dev, #tor on irc.oftc.net)

1077)     </p>
1078)     </li>
1079) 

1080)     <a id="ooniprobePcapsSupport"></a>
1081)     <li>
1082)     <b>Add Support for Reporting Pcaps to OoniBackend and OoniProbe</b>
1083)     <br>
1084)     Effort Level: <i>Medium</i>
1085)     <br>
1086)     Skill Level: <i>Medium</i>
1087)     <br>

1088)     Likely Mentors: <i>Arturo (hellais)</i>

1089)     <p>
1090) The feature should also add support for including only packet capture data that
1091) is relevant to the test being run. This means that the pcap should not contain
1092) all the data sniffed on the users machine, but only that which was generated
1093) and intended to be received by ooniprobe.
1094)     </p>
1095) 
1096)     <p>
1097) This can probably be implemented by setting up a tun/tap device and routing all
1098) the ooniprobe traffic through it and only capturing data sent and received from
1099) that device. The task for the student will also be that of doing research into
1100) what are possible strategies for doing this. <b><a
1101) href="https://trac.torproject.org/projects/tor/ticket/7416">For more
1102) information see ticket 7416.</a></b>
1103)     </p>
1104)     </li>
1105) 

1106)     <a id="improveTorTestCoverage"></a>
1107)     <li>
1108)     <b>Improve test coverage in Tor</b>
1109)     <br>
1110)     Effort Level: <i>Medium</i>
1111)     <br>
1112)     Skill Level: <i>Medium</i>
1113)     <br>

1114)     Likely Mentors: <i>Nick (nickm), David (dgoulet)</i>

1115)     <p>
1116) Right now, our unit test coverage with the tests we ship is around 30%
1117) -- only 30% of the executable lines in our source are reached by the
1118) unit tests.  Improving this test coverage could make Tor development
1119) much more reliable.
1120)     </p>
1121) 
1122)     <p>
1123) So we need better unit tests, and we need better integration tests too.
1124)     </p>
1125) 
1126)     <p>

1127) Improving unit tests would involve refactoring functions to be more

1128) testable, and writing a bunch of unit tests.
1129)     </p>
1130) 
1131)     <p>

1132) Improving integration tests would involve refactoring and improving

1133) the "chutney" program that launches a test tor network, and writing a
1134) bunch of tests to see what works and what doesn't work on such a
1135) network.  It could also involve writing tests using the library "<a
1136) href="https://stem.torproject.org/">stem</a>" to script individual clients on a
1137) Chutney network.
1138)     </p>
1139) 
1140)     <p>
1141) To get a feel for how testing works in Tor today, download Tor and
1142) Chutney, and make sure you can build Tor and use Chutney.  See how the
1143) unit tests work by skimming some of the test code in the src/test
1144) subdirectory.  Try computing test coverage (according to the
1145) instructions in the doc/HACKING file.
1146)     </p>
1147) 
1148)     <p>
1149) Also, have a look at the one current integration test that works on
1150) chutney today: it is a shell script distributed with Tor as
1151) src/test/test-tor-network.sh .  We probably don't want to have all of
1152) our integration tests be written as shell scripts, but it's interesting
1153) to see how one works.
1154)     </p>
1155) 
1156)     <p>
1157) If working on designs for an improved or refactored Chutney, watch out for <a
1158) href="http://www.joelonsoftware.com/articles/fog0000000018.html">"archicture
1159) astronautics"</a>: while it's important that we have a well-designed and
1160) maintainable Chutney architecture, it wouldn't be very useful if a good
1161) architecture were the <em>only</em> outcome here: we need tests too.
1162)     </p>
1163) 
1164)     <p>
1165) As part of the application process, please contribute a patch that makes
1166) a non-trivial improvement to chutney, and/or include a new test for some
1167) interesting Tor function. (Please pick a function that isn't completely
1168) easy to test.)
1169)     </p>
1170)     </li>
1171) 
1172)     <a id="useMoreCores"></a>
1173)     <li>
1174)     <b>Have the Tor daemon use more cores</b>
1175)     <br>
1176)     Effort Level: <i>Medium</i>
1177)     <br>
1178)     Skill Level: <i>Medium</i>
1179)     <br>

1180)     Likely Mentors: <i>Nick (nickm), David (dgoulet)</i>

1181)     <p>
1182) Right now, if you run a busy Tor server on a multicore computer, most of
1183) the cores are mostly unused.  We have a "cpuworker" mechanism to move
1184) expensive computations into worker threads, but that mechanism is
1185) currently only used for a small fraction of our cryptography.  Moving
1186) more work into the worker threads could improve performance immensely.
1187)     </p>
1188) 
1189)     <p>
1190) So it would be great to parallelize our cryptography more in order to
1191) better handle more cores.  See
1192) <a href="https://trac.torproject.org/projects/tor/wiki/org/projects/Tor/MultithreadedCrypto">MultithreadedCrypto</a>
1193) for some background info, and
1194) <a href="https://trac.torproject.org/projects/tor/ticket/7572">ticket 7572</a> for some subtickets
1195) on our tracker.
1196)     </p>
1197) 
1198)     <p>
1199) (If you're reading through the code to see how it works today, you will
1200) also want to have a look at the new implementation for cpuworkers
1201) described in <a href="https://trac.torproject.org/projects/tor/ticket/9682">9682</a>.)
1202)     </p>
1203) 
1204)     <p>
1205) Completing the implementation of ticket #7572 --which would move our
1206) circuit crypto onto separate threads-- could be a good summer project.
1207) Alternatively, moving all of the signature generation and verification
1208) code onto the cpuworkers could be fun.  In either case, you will have
1209) some important architectural decisions to make about how to minimize
1210) shared data between the main thread and the workers, how to avoid
1211) race conditions between them, and how to test it all to make sure it has
1212) no hidden failure cases.
1213)     </p>
1214) 
1215)     <p>
1216) As part of the application process for this project, please contribute a
1217) nontrivial patch to Tor -- ideally, one that will affect some part of
1218) the codebase that you want to work on.
1219)     </p>
1220)     </li>
1221) 
1222)     <a id="improveHiddenServices"></a>
1223)     <li>
1224)     <b>Help improve Tor hidden services</b>
1225)     <br>
1226)     Effort Level: <i>Medium</i>
1227)     <br>
1228)     Skill Level: <i>Medium</i>
1229)     <br>

1230)     Likely Mentors: <i>Nick (nickm), David (dgoulet), George (asn)</i>

1231)     <p>
1232) We're working on a revamp of the entire Tor hidden service design to
1233) improve the security and reliability of the hidden service system.
1234)     </p>
1235) 
1236)     <p>
1237) This is a big project: see

1238) <a href="https://gitweb.torproject.org/torspec.git/tree/proposals/224-rend-spec-ng.txt">proposal

1239) 224</a> for the latest design.  Are you interested in implementing some
1240) part of that?
1241)     </p>
1242) 
1243)     <p>
1244) This is a very ambitious project, so we're deliberately not suggesting
1245) particular sub-topics.  If you're interested in participating, try to
1246) read and understand the <a

1247) href="https://gitweb.torproject.org/torspec.git/tree/rend-spec.txt">existing

1248) design</a> and the design proposal for the new design, and then talk to
1249) us about what part you want to work on.
1250)     </p>
1251) 
1252)     <p>
1253) As part of the application process for this project, please contribute a
1254) nontrivial patch to Tor -- ideally, one that will affect some part of
1255) the codebase that you want to work on.
1256)     </p>
1257)     </li>
1258) 
1259)     <a id="improvedDnsSupport"></a>
1260)     <li>
1261)     <b>Improved DNS support for Tor</b>
1262)     <br>
1263)     Effort Level: <i>Medium</i>
1264)     <br>
1265)     Skill Level: <i>Medium</i>
1266)     <br>

1267)     Likely Mentors: <i>Nick (nickm), David (dgoulet)</i>

1268)     <p>
1269) Right now, you can only use Tor's DNS support to look up IPv4 and IPv6
1270) addresses, and to fetch PTR records.  But DNS can do so much more!
1271)     </p>
1272) 
1273)     <p>
1274) <a

1275) href="https://gitweb.torproject.org/torspec.git/tree/proposals/219-expanded-dns.txt">Proposal

1276) 219</a> describes some new cell types that Tor could use to support
1277) more types of DNS over Tor.
1278)     </p>
1279) 
1280)     <p>
1281) To see how Tor implements its existing DNS lookups, start by tracing the
1282) the connection_exit_begin_resolve() function in src/or/connection_edge.c ,
1283) and see how we pass these requests downwards through src/or/dns.c to the
1284) underlying resolver.  It's not too complicated, but there are some
1285) tricky parts to understand.
1286)     </p>
1287) 
1288)     <p>
1289) As part of the application process for this project, please contribute a
1290) nontrivial patch to Tor -- ideally, one that will affect some part of
1291) the codebase that you want to work on.
1292)     </p>
1293)     </li>
1294) 

1295)     <a id="ahmiaSearch"></a>
1296)     <li>
1297)     <b>Ahmia - Hidden Service Search</b>
1298)     <br>
1299)     Effort Level: <i>Medium</i>
1300)     <br>
1301)     Skill Level: <i>Medium</i>
1302)     <br>
1303)     Likely Mentors: <i>Juha Nurmi (numes), George (asn)</i>
1304)     <p>
1305) 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>.
1306)     </p>
1307) 
1308)     <p>
1309) 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.
1310)     </p>
1311) 
1312)     <p>
1313) 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.
1314)     </p>
1315) 
1316)     <p>
1317) There are several possible directions for this project, including...
1318)     </p>
1319) 
1320)     <ol>
1321)       <li>Improving the search results (very important)<br />
1322)         <ul>
1323)           <li>Tweaking search algorithms</li>
1324)           <li>Adjust Apache Solr</li>
1325)           <li>Enrich the data that is used to rank the search results</li>
1326)         </ul>
1327)       </li>
1328)       <li>Improving UX and UI (very important)<br />
1329)         <ul>
1330)           <li>Showing relevant knowledge</li>
1331)           <li>Design the navigation and information architecture</li>
1332)           <li>HTML5, CSS and Django development</li>
1333)         </ul>
1334)       </li>
1335)       <li>Review code and infrastructure<br />
1336)         <ul>
1337)           <li>Review code and fix bugs</li>
1338)           <li>Writing Django test cases</li>
1339)           <li>Linux configurations, automatizations</li>
1340)         </ul>
1341)       </li>
1342)       <li>Gather statistics over time and publish them<br />
1343)         <ul>
1344)           <li>Gather different kind of stats about Hidden Services</li>
1345)           <li>Publish these stats using HTTP REST API</li>
1346)           <li>Using this API show meaningful tables, charts and visualizations</li>
1347)         </ul>
1348)       </li>
1349)     </ol>
1350)     </p>
1351)     </li>

1352) 
1353)     <a id="exitmap_improvements"></a>
1354)     <li>
1355)     <b>Exitmap Improvements</b>
1356)     <br>
1357)     Effort Level: <i>Medium</i>
1358)     <br>
1359)     Skill Level: <i>Medium</i>
1360)     <br>
1361)     Likely Mentors: <i>Philipp (phw)</i>
1362)     <p>
1363) The Tor Project makes use of the Python tool <a
1364) href="https://gitweb.torproject.org/user/phw/exitmap.git/">Exitmap</a> to
1365) systematically scan for malicious and misbehaving exit relays.  Once such a
1366) relay is found, it is assigned the BadExit flag which prevents clients from
1367) selecting the relay as last hop in their circuit.
1368)     </p>
1369) 
1370)     <p>
1371) Exitmap supports scanning modules which implement a specific scan over
1372) exit relays.  Examples are the DNS module which checks for DNS poisoning
1373) or the patching check module which looks out for tampered file
1374) downloads.
1375)     </p>
1376) 
1377)     <p>
1378) This project is meant to extend exitmap in several ways.  First, it
1379) should be made fully autonomous.  That means that exitmap should be able
1380) to run in the background, periodically fetch new relay descriptors, and
1381) have a smart algorithm which keeps scanning all exit relays
1382) periodically.  Second, exitmap should be able to emulate some user
1383) interaction and dynamically "explore" the web in order to detect
1384) tampering.  Third, unit tests should be added for existing and new code
1385) in order to make the code base more robust.
1386)     </p>
1387)     </li>

1388) 
1389)     <a id="coniks_in_messenger"></a>
1390)     <li>
1391)     <b>Implement and Integrate CONIKS for Tor Messenger</b>
1392)     <br>
1393)     Effort Level: <i>Medium</i>
1394)     <br>
1395)     Skill Level: <i>Medium</i>
1396)     <br>
1397)     Likely Mentors: <i>Marcela, Arlo (arlolra)</i>
1398)     <p>
1399) CONIKS is an end-user key management and verification system for end-to-end
1400) secure communication services, which improves upon existing key management
1401) systems by providing both strong security and better usability using a model
1402) called key transparency. CONIKS does this by requiring providers to manage
1403) tamper-evident, publicly-auditable key directories, which contain mappings from
1404) usernames to public keys, on behalf of their users. This design makes it easier
1405) for users (both "default" users and power users) to establish trust since they
1406) don't have to worry about or even see keys, but users also don't have to
1407) trust the provider to be well-behaved because the CONIKS client can run as
1408) part of the secure messaging app and automatically check that the service
1409) provider doesn’t map spurious keys to their users' usernames, and it can
1410) verify that observed name-to-key mappings are consistent with what other
1411) clients in the system are seeing. Unlike existing key transparency solutions,
1412) CONIKS also provides strong privacy guarantees by employing cryptographic
1413) primitives for robust data obfuscation.
1414)     </p>
1415) 
1416)     <p>
1417) The CONIKS system design, protocols, and proof-of-concept are described in
1418) great detail in the <a
1419) href="https://www.usenix.org/system/files/conference/usenixsecurity15/sec15-paper-melara.pdf">CONIKS
1420) research paper</a>, and basic reference implementations of a CONIKS key server
1421) and a CONIKS client are avialable on <a
1422) href="https://github.com/coniks-sys/coniks-ref-implementation">Github</a>.
1423)     </p>
1424) 
1425)     <p>
1426) This project has two main components: (1) designing and implementing a CONIKS
1427) key server tailored to Tor Messenger users, and (2) building a CONIKS client
1428) which integrates with the Tor Messenger client. One challenge the applicant
1429) will face is ensuring that the key server design is efficient and scalable for
1430) large volumes of users, concurrent traffic and guarantees this scalability even
1431) as Tor Messenger's user base grows. On the client side, the main challenges
1432) will be to focus on space efficiency as well as minimizing computational
1433) overhead when implementing the CONIKS consistency checks, and determining how
1434) to best communicate CONIKS consistency check results to users in the UI. Since
1435) Tor Messenger does not hand out online identities per se, as most online
1436) communication services do (like, say, Twitter, in which each user has a unique
1437) handle), the CONIKS key server for Tor Messenger will have to map usernames
1438) from third-party communication services to the encryption keys used in Tor
1439) Messenger. One additional important challenge that the applicant will have to
1440) help address is ensuring that each such third-party username remains unique in
1441) the Tor Messenger space and that such external, third-party identities are
1442) indeed controlled by the expected user of that third-party communication
1443) service.
1444)     </p>
1445) 
1446)     <p>
1447) Some design and implementation questions have been discussed in <a
1448) href="https://trac.torproject.org/projects/tor/ticket/17961">Ticket #17961</a>.
1449)     </p>
1450) 
1451)     <p>
1452) The applicant should have some familiarity with well-known crypto primitives
1453) and algorithms, as well as have a basic understanding of the key transparency
1454) model. Client side integration will require some basic use of JavaScript.
1455) Consider submitting a patch for <a
1456) href="https://github.com/arlolra/ctypes-otr/issues">one of the open key
1457) verification issues</a> as part of the application process.
1458)     </p>
1459)     </li>

1460) <!--
1461)     <a id=""></a>
1462)     <li>
1463)     <b></b>
1464)     <br>
1465)     Effort Level: <i>Medium</i>
1466)     <br>
1467)     Skill Level: <i>Medium</i>
1468)     <br>
1469)     Likely Mentors: <i>Damian (atagar)</i>
1470)     <p>
1471) 
1472)     </p>
1473) 
1474)     <p>
1475) 
1476)     </p>
1477)     </li>
1478) -->
1479) 

1480)     <li>
1481)     <b>Bring up new ideas!</b>

1482)     <br>

1483)     Don't like any of these? Look at the <a

1484)     href="/press/presskit/2008-12-19-roadmap-full.pdf">Tor development

1485)     roadmap</a> for more ideas, or just try out Tor and Tor Browser,

1486)     and find out what you think needs fixing.

1487)     Some of the <a href="<spectree>proposals">current proposals</a>

1488)     might also be short on developers.
1489)     </li>

1490) 

1491)     </ol>

1492) 

1493)     <a id="OtherCoding"></a>
1494)     <h2><a class="anchor" href="#OtherCoding">Other Coding and Design related ideas</a></h2>
1495)     <ol>
1496)     <li>Tor relays don't work well on Windows XP. On
1497)     Windows, Tor uses the standard <tt>select()</tt> system
1498)     call, which uses space in the non-page pool. This means
1499)     that a medium sized Tor relay will empty the non-page pool, <a

1500)     href="<wiki>doc/WindowsBufferProblems">causing

1501)     havoc and system crashes</a>. We should probably be using overlapped IO
1502)     instead. One solution would be to teach <a
1503)     href="http://www.monkey.org/~provos/libevent/">libevent</a> how to use
1504)     overlapped IO rather than select() on Windows, and then adapt Tor to
1505)     the new libevent interface. Christian King made a
1506)     <a href="https://svn.torproject.org/svn/libevent-urz/trunk/">good
1507)     start</a> on this in the summer of 2007.</li>

1508) 

1509)     <li>We need a flexible simulator framework for studying end-to-end
1510)     traffic confirmation attacks. Many researchers have whipped up ad hoc
1511)     simulators to support their intuition either that the attacks work
1512)     really well or that some defense works great. Can we build a simulator
1513)     that's clearly documented and open enough that everybody knows it's
1514)     giving a reasonable answer? This will spur a lot of new research.
1515)     See the entry <a href="#Research">below</a> on confirmation attacks for
1516)     details on the research side of this task &mdash; who knows, when it's
1517)     done maybe you can help write a paper or three also.</li>

1518) 

1519)     <li>Tor 0.1.1.x and later include support for hardware crypto
1520)     accelerators via OpenSSL. It has been lightly tested and is
1521)     possibly very buggy.  We're looking for more rigorous testing,

1522)     performance analysis, and optimally, code fixes to OpenSSL and

1523)     Tor if needed.</li>

1524) 

1525)     <li>Write a <a
1526)     href="https://secure.wikimedia.org/wikipedia/en/wiki/Fuzz_testing">fuzzer</a>
1527)     for Tor to discover security vulnerabilities. Determine if there
1528)     are good fuzzing frameworks out there for what we want. Win fame by

1529)     getting credit when we put out a new release because of you!</li>

1530) 

1531)     <li>Tor uses TCP for transport and TLS for link
1532)     encryption. This is nice and simple, but it means all cells
1533)     on a link are delayed when a single packet gets dropped, and
1534)     it means we can only reasonably support TCP streams. We have a <a

1535)     href="<page docs/faq>#TransportIPnotTCP">list

1536)     of reasons why we haven't shifted to UDP transport</a>, but it would
1537)     be great to see that list get shorter. We also have a proposed <a

1538)     href="<specblob>proposals/100-tor-spec-udp.txt">specification

1539)     for Tor and
1540)     UDP</a> &mdash; please let us know what's wrong with it.</li>

1541) 

1542)     <li>We're not that far from having IPv6 support for destination addresses
1543)     (at exit nodes). If you care strongly about IPv6, that's probably the
1544)     first place to start.</li>

1545) 

1546)     <li>We need a way to generate the website diagrams (for example, the "How
1547)     Tor Works" pictures on the <a href="<page about/overview>">overview page</a>
1548)     from source, so we can translate them as UTF-8 text rather than edit
1549)     them by hand with Gimp. We might want to
1550)     integrate this as an wml file so translations are easy and images are
1551)     generated in multiple languages whenever we build the website.</li>

1552) 

1553)     <li>How can we make the various LiveCD/USB systems easier
1554)     to maintain, improve, and document?  One example is <a

1555)     href="https://tails.boum.org/">The Amnesic Incognito Live

1556)     System</a>.
1557)     </li>

1558) 

1559)     <li>
1560)     Another anti-censorship project is to try to make Tor
1561)     more scanning-resistant.  Right now, an adversary can identify <a

1562)     href="<specblob>proposals/125-bridges.txt">Tor bridges</a>

1563)     just by trying to connect to them, following the Tor protocol,
1564)     and seeing if they respond.  To solve this, bridges could <a
1565)     href="<svnprojects>design-paper/blocking.html#tth_sEc9.3">act like
1566)     webservers</a> (HTTP or HTTPS) when contacted by port-scanning tools,
1567)     and not act like bridges until the user provides a bridge-specific key.
1568)     To start, check out Shane Pope's <a
1569)     href="http://dl.dropbox.com/u/37735/index.html">thesis and prototype</a>.
1570)     </li>

1571) 

1572)     </ol>

1573) 

1574)     <a id="Research"></a>
1575)     <h2><a class="anchor" href="#Research">Research</a></h2>
1576)     <ol>
1577)     <li>The "end-to-end traffic confirmation attack":
1578)     by watching traffic at Alice and at Bob, we can <a
1579)     href="http://freehaven.net/anonbib/#danezis:pet2004">compare
1580)     traffic signatures and become convinced that we're watching the same
1581)     stream</a>. So far Tor accepts this as a fact of life and assumes this
1582)     attack is trivial in all cases. First of all, is that actually true? How
1583)     much traffic of what sort of distribution is needed before the adversary
1584)     is confident he has won? Are there scenarios (e.g. not transmitting much)
1585)     that slow down the attack? Do some traffic padding or traffic shaping
1586)     schemes work better than others?</li>
1587)     <li>A related question is: Does running a relay/bridge provide additional
1588)     protection against these timing attacks? Can an external adversary that can't
1589)     see inside TLS links still recognize individual streams reliably?
1590)     Does the amount of traffic carried degrade this ability any? What if the
1591)     client-relay deliberately delayed upstream relayed traffic to create a queue
1592)     that could be used to mimic timings of client downstream traffic to make it
1593)     look like it was also relayed? This same queue could also be used for masking
1594)     timings in client upstream traffic with the techniques from <a
1595)     href="http://www.freehaven.net/anonbib/#ShWa-Timing06">adaptive padding</a>,
1596)     but without the need for additional traffic. Would such an interleaving of
1597)     client upstream traffic obscure timings for external adversaries? Would the
1598)     strategies need to be adjusted for asymmetric links? For example, on
1599)     asymmetric links, is it actually possible to differentiate client traffic from
1600)     natural bursts due to their asymmetric capacity? Or is it easier than
1601)     symmetric links for some other reason?</li>
1602)     <li>Repeat Murdoch and Danezis's <a
1603)     href="http://www.cl.cam.ac.uk/~sjm217/projects/anon/#torta">attack from
1604)     Oakland 05</a> on the current Tor network. See if you can learn why it
1605)     works well on some nodes and not well on others. (My theory is that the
1606)     fast nodes with spare capacity resist the attack better.) If that's true,
1607)     then experiment with the RelayBandwidthRate and RelayBandwidthBurst
1608)     options to run a relay that is used as a client while relaying the
1609)     attacker's traffic: as we crank down the RelayBandwidthRate, does the
1610)     attack get harder? What's the right ratio of RelayBandwidthRate to
1611)     actually capacity? Or is it a ratio at all? While we're at it, does a
1612)     much larger set of candidate relays increase the false positive rate
1613)     or other complexity for the attack? (The Tor network is now almost two
1614)     orders of magnitude larger than it was when they wrote their paper.) Be
1615)     sure to read <a href="http://freehaven.net/anonbib/#clog-the-queue">Don't
1616)     Clog the Queue</a> too.</li>
1617)     <li>The "routing zones attack": most of the literature thinks of
1618)     the network path between Alice and her entry node (and between the
1619)     exit node and Bob) as a single link on some graph. In practice,
1620)     though, the path traverses many autonomous systems (ASes), and <a
1621)     href="http://freehaven.net/anonbib/#feamster:wpes2004">it's not uncommon
1622)     that the same AS appears on both the entry path and the exit path</a>.
1623)     Unfortunately, to accurately predict whether a given Alice, entry,
1624)     exit, Bob quad will be dangerous, we need to download an entire Internet
1625)     routing zone and perform expensive operations on it. Are there practical
1626)     approximations, such as avoiding IP addresses in the same /8 network?</li>
1627)     <li>Other research questions regarding geographic diversity consider
1628)     the tradeoff between choosing an efficient circuit and choosing a random
1629)     circuit. Look at Stephen Rollyson's <a
1630)     href="http://swiki.cc.gatech.edu:8080/ugResearch/uploads/7/ImprovingTor.pdf">position
1631)     paper</a> on how to discard particularly slow choices without hurting
1632)     anonymity "too much". This line of reasoning needs more work and more
1633)     thinking, but it looks very promising.</li>
1634)     <li>Tor doesn't work very well when relays have asymmetric bandwidth
1635)     (e.g. cable or DSL). Because Tor has separate TCP connections between
1636)     each hop, if the incoming bytes are arriving just fine and the outgoing
1637)     bytes are all getting dropped on the floor, the TCP push-back mechanisms
1638)     don't really transmit this information back to the incoming streams.
1639)     Perhaps Tor should detect when it's dropping a lot of outgoing packets,
1640)     and rate-limit incoming streams to regulate this itself? I can imagine
1641)     a build-up and drop-off scheme where we pick a conservative rate-limit,
1642)     slowly increase it until we get lost packets, back off, repeat. We
1643)     need somebody who's good with networks to simulate this and help design
1644)     solutions; and/or we need to understand the extent of the performance
1645)     degradation, and use this as motivation to reconsider UDP transport.</li>
1646)     <li>A related topic is congestion control. Is our
1647)     current design sufficient once we have heavy use? Maybe
1648)     we should experiment with variable-sized windows rather
1649)     than fixed-size windows? That seemed to go well in an <a

1650)     href="http://www.psc.edu/index.php/hpn-ssh/638">ssh

1651)     throughput experiment</a>. We'll need to measure and tweak, and maybe
1652)     overhaul if the results are good.</li>
1653)     <li>Our censorship-resistance goals include preventing
1654)     an attacker who's looking at Tor traffic on the wire from <a
1655)     href="<svnprojects>design-paper/blocking.html#sec:network-fingerprint">distinguishing
1656)     it from normal SSL traffic</a>. Obviously we can't achieve perfect
1657)     steganography and still remain usable, but for a first step we'd like to
1658)     block any attacks that can win by observing only a few packets. One of
1659)     the remaining attacks we haven't examined much is that Tor cells are 512
1660)     bytes, so the traffic on the wire may well be a multiple of 512 bytes.
1661)     How much does the batching and overhead in TLS records blur this on the
1662)     wire? Do different buffer flushing strategies in Tor affect this? Could
1663)     a bit of padding help a lot, or is this an attack we must accept?</li>
1664)     <li>Tor circuits are built one hop at a time, so in theory we have the
1665)     ability to make some streams exit from the second hop, some from the
1666)     third, and so on. This seems nice because it breaks up the set of exiting
1667)     streams that a given relay can see. But if we want each stream to be safe,
1668)     the "shortest" path should be at least 3 hops long by our current logic, so
1669)     the rest will be even longer. We need to examine this performance / security
1670)     tradeoff.</li>
1671)     <li>It's not that hard to DoS Tor relays or directory authorities. Are client
1672)     puzzles the right answer? What other practical approaches are there? Bonus
1673)     if they're backward-compatible with the current Tor protocol.</li>
1674)     <li>Programs like <a

1675)     href="<page docs/torbutton/index>">Torbutton</a> aim to hide

1676)     your browser's UserAgent string by replacing it with a uniform answer for
1677)     every Tor user. That way the attacker can't splinter Tor's anonymity set
1678)     by looking at that header. It tries to pick a string that is commonly used
1679)     by non-Tor users too, so it doesn't stand out. Question one: how badly
1680)     do we hurt ourselves by periodically updating the version of Firefox
1681)     that Torbutton claims to be? If we update it too often, we splinter the
1682)     anonymity sets ourselves. If we don't update it often enough, then all the
1683)     Tor users stand out because they claim to be running a quite old version
1684)     of Firefox. The answer here probably depends on the Firefox versions seen
1685)     in the wild. Question two: periodically people ask us to cycle through N
1686)     UserAgent strings rather than stick with one. Does this approach help,
1687)     hurt, or not matter? Consider: cookies and recognizing Torbutton users
1688)     by their rotating UserAgents; malicious websites who only attack certain
1689)     browsers; and whether the answers to question one impact this answer.
1690)     </li>
1691)     <li>How many bridge relays do you need to know to maintain
1692)     reachability? We should measure the churn in our bridges. If there is
1693)     lots of churn, are there ways to keep bridge users more likely to stay
1694)     connected?
1695)     </li>
1696)     </ol>

1697) 

1698)     <p>
1699)     <a href="<page about/contact>">Let us know</a> if you've made progress on any
1700)     of these!
1701)     </p>
1702)   </div>
1703)   <!-- END MAINCOL -->
1704)   <div id = "sidecol">
1705) #include "side.wmi"
1706) #include "info.wmi"
1707)   </div>
1708)   <!-- END SIDECOL -->
1709) </div>
1710) <!-- END CONTENT -->