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

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

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

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

42)     programs that interface to Tor</a>. Which ones are useful in which
43)     situations? Please help us test them out and document your results.</li>
44)     </ol>
45)     
46)     <a id="Advocacy"></a>
47)     <h2><a class="anchor" href="#Advocacy">Advocacy</a></h2>
48)     <ol>

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

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

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

54)     <a

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

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

57)     <li>Create a poster, or a set of posters, around a theme,

58)     such as "Tor for Freedom!".</li>

59)     <li>Create a t-shirt design that incorporates "Congratulations!
60)     You are using Tor!" in any language.</li>

61)     </ol>
62)     

63)     <a id="Projects"></a>
64)     <h2><a class="anchor" href="#Projects">Projects</a></h2>
65)     
66)     <p>
67)     Below are a list of Tor related projects we're developing and/or
68)     maintaining. Most discussions happen on IRC so if you're interested in any
69)     of these (or you have a project idea of your own), then please <a

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

73)     </p>
74)     
75)     <table id="projects">
76)       <tr>
77)         <th>Name</th>
78)         <th>Category</th>
79)         <th>Language</th>
80)         <th>Activity</th>
81)         <th>Contributors</th>
82)       </tr>
83)       
84)       <tr>
85)         <td><a href="#project-tor">Tor</a></td>
86)         <td>Core</td>
87)         <td>C</td>
88)         <td>Heavy</td>

89)         <td>nickm, arma, Sebastian</td>

90)       </tr>
91)       
92)       <tr class="alt">

93)         <td>*<a href="#project-jtor">JTor</a></td>
94)         <td>Core</td>
95)         <td>Java</td>
96)         <td>None</td>
97)         <td></td>
98)       </tr>
99)       
100)       <tr>

101)         <td><a href="#project-tbb">TBB</a></td>
102)         <td>Usability</td>

103)         <td>Sys Admin</td>
104)         <td>Moderate</td>

105)         <td>Erinn</td>

106)       </tr>
107)       

108)       <tr class="alt">

109)         <td><a href="#project-tails">Tails</a></td>

110)         <td>Usability</td>

111)         <td>Sys Admin</td>

112)         <td>Heavy</td>

113)         <td><a href="https://tails.boum.org/chat/">#tails</a></td>

114)       </tr>
115)       

116)       <tr>

117)         <td><a href="#project-torsocks">Torsocks</a></td>
118)         <td>Usability</td>
119)         <td>C</td>

120)         <td>None</td>

121)         <td>mwenge</td>
122)       </tr>
123)       

124)       <tr class="alt">

125)         <td>*<a href="#project-torouter">Torouter</a></td>
126)         <td>Usability</td>

127)         <td>Sys Admin</td>

128)         <td>Light</td>
129)         <td>ioerror, Runa</td>
130)       </tr>
131)       

132)       <tr>

133)         <td><a href="#project-vidalia">Vidalia</a></td>
134)         <td>User Interface</td>
135)         <td>C++, Qt</td>
136)         <td>Light</td>
137)         <td>chiiph</td>
138)       </tr>
139)       

140)       <tr class="alt">

141)         <td><a href="#project-arm">Arm</a></td>
142)         <td>User Interface</td>
143)         <td>Python, Curses</td>

144)         <td>Light</td>

145)         <td>atagar</td>
146)       </tr>
147)       

148)       <tr>

149)         <td><a href="#project-orbot">Orbot</a></td>
150)         <td>User Interface</td>
151)         <td>Java</td>

152)         <td>Moderate</td>

153)         <td>n8fr8</td>
154)       </tr>
155)       

156)       <tr class="alt">

157)         <td><a href="#project-torbutton">Torbutton</a></td>
158)         <td>Browser Add-on</td>
159)         <td>Javascript</td>
160)         <td>Moderate</td>
161)         <td>mikeperry</td>
162)       </tr>
163)       

164)       <tr>

165)         <td><a href="#project-obfsproxy">Obfsproxy</a></td>
166)         <td>Client Add-on</td>
167)         <td>C</td>
168)         <td>Moderate</td>
169)         <td>nickm, asn</td>
170)       </tr>
171)       
172)       <tr class="alt">

173)         <td>*<a href="#project-thandy">Thandy</a></td>
174)         <td>Updater</td>
175)         <td>Python</td>
176)         <td>Light</td>

177)         <td>chiiph, Erinn, nickm</td>

178)       </tr>
179)       

180)       <tr>

181)         <td>*<a href="#project-ooni-probe">Ooni Probe</a></td>
182)         <td>Scanner</td>
183)         <td>Python</td>
184)         <td>Moderate</td>
185)         <td>hellais, ioerror</td>
186)       </tr>
187)       
188)       <tr class="alt">

189)         <td><a href="#project-shadow">Shadow</a></td>
190)         <td>Experimentation</td>
191)         <td>C, Python</td>
192)         <td>Moderate</td>
193)         <td>robgjansen</td>
194)       </tr>
195)       
196)       <tr>

197)         <td><a href="#project-torctl">TorCtl</a></td>
198)         <td>Library</td>
199)         <td>Python</td>
200)         <td>Light</td>
201)         <td>mikeperry</td>
202)       </tr>
203)       

204)       <tr class="alt">

205)         <td>*<a href="#project-stem">Stem</a></td>
206)         <td>Library</td>
207)         <td>Python</td>
208)         <td>Heavy</td>
209)         <td>atagar</td>
210)       </tr>
211)       

212)       <tr>

213)         <td><a href="#project-metrics">Metrics</a></td>
214)         <td>Client Service</td>
215)         <td>Java</td>
216)         <td>Heavy</td>
217)         <td>karsten</td>
218)       </tr>
219)       

220)       <tr class="alt">

221)         <td><a href="#project-torstatus">TorStatus</a></td>
222)         <td>Client Service</td>

223)         <td>Python, Django</td>

224)         <td>None</td>
225)         <td></td>
226)       </tr>
227)       

228)       <tr>

229)         <td><a href="#project-weather">Weather</a></td>
230)         <td>Client Service</td>
231)         <td>Python</td>

232)         <td>None</td>

233)         <td>kaner</td>
234)       </tr>
235)       

236)       <tr class="alt">

237)         <td><a href="#project-gettor">GetTor</a></td>
238)         <td>Client Service</td>
239)         <td>Python</td>

240)         <td>None</td>

241)         <td>kaner</td>

242)       </tr>
243)       

244)       <tr>

245)         <td><a href="#project-torcheck">TorCheck</a></td>
246)         <td>Client Service</td>
247)         <td>Python, Perl</td>
248)         <td>None</td>
249)         <td></td>
250)       </tr>
251)       

252)       <tr class="alt">

253)         <td><a href="#project-bridgedb">BridgeDB</a></td>
254)         <td>Backend Service</td>
255)         <td>Python</td>

256)         <td>None</td>

257)         <td>kaner, nickm</td>

258)       </tr>
259)       

260)       <tr>

261)         <td><a href="#project-torflow">TorFlow</a></td>
262)         <td>Backend Service</td>
263)         <td>Python</td>

264)         <td>Moderate</td>

265)         <td>mikeperry</td>
266)       </tr>
267)       

268)       <tr class="alt">

269)         <td>*<a href="#project-torbel">TorBEL</a></td>
270)         <td>Backend Service</td>
271)         <td>Python</td>
272)         <td>None</td>
273)         <td>Sebastian</td>
274)       </tr>
275)     </table>
276)     
277)     <sub>
278)     * Project is still in an alpha state.
279)     </sub>
280)     
281)     <br /><br />
282)     
283)     <a id="project-tor"></a>
284)     <h3>Tor (<a href="https://gitweb.torproject.org/tor.git">code</a>, <a
285)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Tor+Client&component=Tor+Relay&component=vidalia&order=priority">bug
286)     tracker</a>)</h3>
287)     
288)     <p>
289)     Central project, providing the core software for using and participating in
290)     the Tor network. Numerous people contribute to the project to varying
291)     extents, but the chief architects are Nick Mathewson and Roger Dingledine.
292)     </p>
293)     
294)     <p>
295)     <b>Project Ideas:</b><br />
296)     <i><a href="#resistCensorship">Improving Tor's ability to resist
297)     censorship</a></i><br />

298)     <i><a href="#unitTesting">Improve our unit testing process</a></i><br />
299)     <i><a href="#simulateSlowConnections">Simulator for slow Internet connections</a></i>

300)     </p>
301)     

302)     <a id="project-jtor"></a>
303)     <h3><a href="https://github.com/brl/JTor/wiki">JTor</a> (<a
304)     href="https://github.com/brl/JTor">code</a>, <a
305)     href="https://github.com/brl/JTor/issues">bug
306)     tracker</a>)</h3>
307)     
308)     <p>
309)     Java implementation of Tor and successor to <a
310)     href="http://onioncoffee.sourceforge.net/">OnionCoffee</a>. This project
311)     isn't yet complete, and has been inactive since Fall 2010.
312)     </p>
313)     

314)     <a id="project-tbb"></a>
315)     <h3><a href="<page projects/torbrowser>">Tor Browser Bundle</a> (<a
316)     href="https://gitweb.torproject.org/torbrowser.git">code</a>, <a
317)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Tor+bundles/installation&order=priority">bug
318)     tracker</a>)</h3>
319)     
320)     <p>
321)     The Tor Browser Bundle is an easy-to-use portable package of Tor, Vidalia,
322)     and Firefox preconfigured to work together out of the box. This is actively
323)     being worked on by Erinn Clark.
324)     </p>
325)     
326)     <p>
327)     <b>Project Ideas:</b><br />
328)     <i><a href="#auditTBB">Audit Tor Browser Bundles for data leaks</a></i><br />
329)     <i><a href="#usabilityTesting">Usability testing of Tor</a></i>
330)     </p>
331)     

332)     <a id="project-tails"></a>

333)     <h3><a href="https://tails.boum.org/">The Amnesic Incognito Live System</a> (<a

334)     href="http://git.immerda.ch/?p=amnesia.git;a=summary">code</a>, <a

335)     href="https://tails.boum.org/bugs/">bug

336)     tracker</a>)</h3>
337)     
338)     <p>

339)     The Amnesic Incognito Live System is a live CD/USB distribution

340)     preconfigured so that everything is safely routed through Tor and leaves no
341)     trace on the local system. This is a merger of the Amnesia and <a
342)     href="http://www.anonymityanywhere.com/incognito/">Incognito</a> projects,
343)     and still under very active development.
344)     </p>
345)     

346)     <p>
347)     <b>Project Ideas:</b><br />
348)     <i><a href="#tailsStartMenu">Custom GDM3 startup menu, aka.
349)     tails-greeter</a></i><br />
350)     <i><a href="#tailsMetadataAnonymizing">Meta-data anonymizing toolkit for
351)     file publication</a></i><br />
352)     <i><a href="#tailsDebianLive">Improve Debian Live support for
353)     persistence</a></i>
354)     </p>
355)     

356)     <a id="project-torsocks"></a>
357)     <h3><a href="http://code.google.com/p/torsocks/">Torsocks</a> (<a
358)     href="https://gitweb.torproject.org/torsocks.git">code</a>, <a
359)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torify&order=priority">bug
360)     tracker</a>)</h3>
361)     
362)     <p>
363)     Utility for adapting other applications to work with Tor. Development has
364)     slowed and compatibility issues remain with some platforms, but it's
365)     otherwise feature complete.
366)     </p>
367)     
368)     <p>
369)     <b>Project Ideas:</b><br />
370)     <i><a href="#torsocksForOSX">Make torsocks/dsocks work on OS X</a></i>
371)     </p>
372)     
373)     <a id="project-torouter"></a>
374)     <h3><a

375)     href="<wiki>doc/Torouter">Torouter</a> (<a

376)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torouter&order=priority">bug
377)     tracker</a>)</h3>
378)     
379)     <p>
380)     Project to provide an easy-to-use, embedded Tor instance for routers. This

381)     had high activity in late 2010, but has since been rather quiet.

382)     </p>
383)     
384)     <a id="project-vidalia"></a>
385)     <h3><a href="<page projects/vidalia>">Vidalia</a> (<a

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

387)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Vidalia&order=priority">bug
388)     tracker</a>)</h3>
389)     
390)     <p>
391)     The most commonly used user interface for Tor. Matt Edman started the
392)     project in 2006 and brought it to its current stable state. Development
393)     slowed for several years, though Tomás Touceda has since taken a lead with
394)     pushing the project forward.
395)     </p>
396)     
397)     <p>
398)     <b>Project Ideas:</b><br />
399)     <i><a href="#vidaliaStatusEventInterface">Tor Controller Status Event Interface for Vidalia</a></i><br />
400)     <i><a href="#vidaliaNetworkMap">An Improved and More Usable Network Map in Vidalia</a></i>
401)     </p>
402)     
403)     <a id="project-arm"></a>
404)     <h3><a href="http://www.atagar.com/arm/">Arm</a> (<a

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

406)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=arm&order=priority">bug
407)     tracker</a>)</h3>
408)     
409)     <p>
410)     Command-line monitor for Tor. This has been under very active development
411)     by its author, Damian Johnson, since early 2009 to make it a better
412)     general-purpose controller for *nix environments.
413)     </p>
414)     

415)     <!--

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

418)     <i><a href="#armClientMode">Client Mode Use Cases for Arm</a></i><br />
419)     <i><a href="#armGui">GUI for Arm</a></i>

420)     </p>

421)     -->

422)     
423)     <a id="project-orbot"></a>
424)     <h3><a href="https://guardianproject.info/apps/orbot/">Orbot</a> (<a

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

426)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Orbot&order=priority">bug
427)     tracker</a>)</h3>
428)     
429)     <p>
430)     Provides Tor on the Android platform. This was under very active
431)     development up through Fall 2010, after which things have been quiet.
432)     </p>
433)     
434)     <p>
435)     <b>Project Ideas:</b><br />

436)     <i><a href="#orbot-torbutton">TorButton for Mobile Firefox 4 or Custom Browser on Android</a></i><br />
437)     <i><a href="#orbot-userInterface">Build a better user interface for Orbot</a></i><br />
438)     <i><a href="#orbot-optimisation">Core Tor mobile optimisation</a></i><br />
439)     <i><a href="#orbot-orlibAndOutreach">Orbot integration library and community outreach</a></i>

440)     </p>
441)     
442)     <a id="project-torbutton"></a>
443)     <h3><a href="<page torbutton/index>">Torbutton</a> (<a
444)     href="https://gitweb.torproject.org/torbutton.git">code</a>, <a
445)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torbutton&order=priority">bug
446)     tracker</a>)</h3>
447)     
448)     <p>
449)     Firefox addon that addresses many of the client-side threats to browsing
450)     the Internet anonymously. Mike has since continued to adapt it to new
451)     threats, updated versions of Firefox, and possibly <a
452)     href="https://blog.torproject.org/blog/google-chrome-incognito-mode-tor-and-fingerprinting">Chrome
453)     as well</a>.
454)     </p>
455)     
456)     <p>
457)     <b>Project Ideas:</b><br />
458)     <i><a href="#torbuttonForThunderbird">Torbutton equivalent for Thunderbird</a></i>
459)     </p>
460)     

461)     <a id="project-obfsproxy"></a>
462)     <h3><a href="https://gitweb.torproject.org/obfsproxy.git/tree/HEAD:/doc">Obfsproxy</a> (<a
463)     href="https://gitweb.torproject.org/obfsproxy.git">code</a>, <a
464)     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
465)     tracker</a>)</h3>
466)     
467)     <p>
468)     A proxy that shapes Tor traffic, making it harder for censors to detect and
469)     block Tor.
470)     </p>
471)     

472)     <a id="project-thandy"></a>
473)     <h3>Thandy (<a
474)     href="https://gitweb.torproject.org/thandy.git">code</a>)</h3>
475)     
476)     <p>
477)     Updater for Tor. The project began in the Summer of 2008 but wasn't
478)     completed. Recently interest in it has been rekindled and many aspects of
479)     its design (including the language it'll be in) are currently in flux.
480)     </p>
481)     

482)     <a id="project-ooni-probe"></a>
483)     <h3>Ooni Probe (<a
484)     href="https://gitweb.torproject.org/ooni-probe.git">code</a>, <a
485)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Ooni&order=priority">bug
486)     tracker</a>)</h3>
487)     
488)     <p>
489)     Censorship scanner, checking your local connection for blocked or modified
490)     content.
491)     </p>
492)     

493)     <a id="project-shadow"></a>
494)     <h3><a href="https://shadow.cs.umn.edu/">Shadow</a> (<a
495)     href="https://github.com/shadow">code</a>, <a
496)     href="https://github.com/shadow/shadow/issues">bug
497)     tracker</a>)</h3>
498)     
499)     <p>
500)     Shadow is a discrete-event network simulator that runs the real
501)     Tor software as a plug-in. Shadow is open-source software that enables
502)     accurate, efficient, controlled, and repeatable Tor experimentation.
503)     </p>
504)     

505)     <a id="project-torctl"></a>
506)     <h3>TorCtl (<a
507)     href="https://gitweb.torproject.org/pytorctl.git">code</a>, <a
508)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torctl&order=priority">bug
509)     tracker</a>)</h3>
510)     
511)     <p>
512)     Python bindings and utilities for using the Tor control port. It has been
513)     stable for several years, with only minor revisions.
514)     </p>
515)     

516)     <a id="project-stem"></a>
517)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/doc/stem">Stem</a> (<a
518)     href="https://gitweb.torproject.org/stem.git">code</a>, <a
519)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Stem&order=priority">bug
520)     tracker</a>)</h3>
521)     
522)     <p>
523)     Python controller library with a similar scope to TorCtl, but with better
524)     testing, documentation, and API. This project is not yet feature complete.
525)     </p>
526)     

527)     <p>
528)     <b>Project Ideas:</b><br />
529)     <i><a href="#stemPathsupport">Stem PathSupport Capabilities</a></i>
530)     </p>
531)     

532)     <a id="project-metrics"></a>
533)     <h3><a href="https://metrics.torproject.org/">Metrics</a> (code: <a
534)     href="https://gitweb.torproject.org/metrics-db.git">db</a>, <a
535)     href="https://gitweb.torproject.org/metrics-utils.git">utils</a>, <a
536)     href="https://gitweb.torproject.org/metrics-web.git">web</a>, <a
537)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Metrics&order=priority">bug
538)     tracker</a>)</h3>
539)     
540)     <p>
541)     Processing and analytics of consensus data, provided to users via the
542)     metrics portal. This has been under active development for several years by
543)     Karsten Loesing.
544)     </p>
545)     

546)     <p>
547)     <b>Project Ideas:</b><br />
548)     <i><a href="#metricsSearch">Searchable Tor descriptor and Metrics data archive</a></i> (Python/Django?)
549)     </p>
550)     

551)     <a id="project-torstatus"></a>
552)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/TorStatus">TorStatus</a> (<a

553)     href="https://gitweb.torproject.org/torstatus.git">code</a>)</h3>

554)     
555)     <p>
556)     Portal providing an overview of the Tor network, and details on any of its
557)     current relays. Though very actively used, this project has been

558)     unmaintained for a long while. The <a
559)     href="https://svn.torproject.org/svn/torstatus/trunk/">original
560)     codebase</a> was written in PHP, and students from Wesleyan wrote the new
561)     Django counterpart.

562)     </p>
563)     
564)     <a id="project-weather"></a>
565)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/Weather">Weather</a> (<a
566)     href="https://gitweb.torproject.org/weather.git">code</a>, <a
567)     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
568)     tracker</a>)</h3>
569)     
570)     <p>
571)     Provides automatic notification to subscribed relay operators when their
572)     relay's unreachable. This underwent a rewrite by the <a
573)     href="http://hfoss.wesleyan.edu/">Wesleyan HFOSS team</a>, which went live
574)     in early 2011.
575)     </p>
576)     
577)     <a id="project-gettor"></a>
578)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/EmailAutoResponder">GetTor</a> (<a

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

580)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=GetTor&order=priority">bug
581)     tracker</a>)</h3>
582)     
583)     <p>
584)     E-mail autoresponder providing Tor's packages over SMTP. This has been
585)     relatively unchanged for quite a while.
586)     </p>
587)     
588)     <a id="project-torcheck"></a>
589)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/TorCheck">TorCheck</a> (<a
590)     href="https://svn.torproject.org/svn/check/trunk/">code</a>, <a
591)     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
592)     tracker</a>)</h3>
593)     
594)     <p>
595)     Provides a simple site for determining if the visitor is using Tor or not.
596)     This has been relatively unchanged for quite a while.
597)     </p>
598)     
599)     <a id="project-bridgedb"></a>
600)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/BridgeDB">BridgeDB</a> (<a
601)     href="https://gitweb.torproject.org/bridgedb.git">code</a>, <a
602)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=BridgeDB&order=priority">bug
603)     tracker</a>)</h3>
604)     
605)     <p>
606)     Backend bridge distributor, handling the various pools they're distributed
607)     in. This was actively developed until Fall of 2010.
608)     </p>
609)     
610)     <a id="project-torflow"></a>
611)     <h3><a href="https://trac.torproject.org/projects/tor/wiki/projects/TorFlow">TorFlow</a> (<a
612)     href="https://gitweb.torproject.org/torflow.git">code</a>, <a
613)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=Torflow&order=priority">bug
614)     tracker</a>)</h3>
615)     
616)     <p>
617)     Library and collection of services for actively monitoring the Tor network.
618)     These include the Bandwidth Scanners (measuring throughput of relays) and
619)     SoaT (scans for malicious or misconfigured exit nodes). SoaT was last
620)     actively developed in the Summer of 2010, and the Bandwidth Scanners a few
621)     months later. Both have been under active use since then, but development
622)     has stopped.
623)     </p>
624)     
625)     <a id="project-torbel"></a>
626)     <h3><a
627)     href="https://trac.torproject.org/projects/tor/wiki/projects/TorBulkExitlist">TorBEL</a> (<a
628)     href="https://gitweb.torproject.org/tordnsel.git">code</a>, <a
629)     href="https://trac.torproject.org/projects/tor/query?status=accepted&status=assigned&status=needs_review&status=new&status=reopened&component=TorDNSEL/TorBEL&order=priority">bug
630)     tracker</a>)</h3>
631)     
632)     <p>
633)     The Tor Bulk Exitlist provides a method of identifying if IPs belong to
634)     exit nodes or not. This is a replacement for TorDNSEL which is a stable
635)     (though unmaintained) Haskell application for this purpose. The initial
636)     version of TorBEL was started in GSOC 2010 but since then the project has
637)     been inactive.
638)     </p>
639)     

640)     <a id="Coding"></a>
641)     <a id="Summer"></a>

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

643)     
644)     <p>
645)     You may find some of these projects to be good <a href="<page

646)     about/gsoc>">Google Summer of Code 2011</a> ideas. We have labelled each idea

647)     with how useful it would be to the overall Tor project (priority), how
648)     much work we expect it would be (effort level), how much clue you should
649)     start with (skill level), and which of our <a href="<page

650)     about/corepeople>">core developers</a> would be good mentors.

651)     If one or more of these ideas looks promising to you, please <a
652)     href="<page about/contact>">contact us</a> to discuss your plans rather than
653)     sending blind applications. You may also want to propose your own project
654)     idea &mdash; which often results in the best applications.
655)     </p>
656)     
657)     <ol>
658)     

659)     <a id="auditTBB"></a>

660)     <li>

661)     <b>Audit Tor Browser Bundles for data leaks</b>

662)     <br>

663)     Priority: <i>High</i>

664)     <br>

665)     Effort Level: <i>High</i>

666)     <br>

667)     Skill Level: <i>Medium</i>

668)     <br>

669)     Likely Mentors: <i>Erinn and Jacob</i>

670)     <p>The Tor Browser Bundle incorporates Tor, Firefox, Polipo, and the Vidalia

671)     user interface (and optionally the <a href="http://pidgin.im/">Pidgin</a>
672)     Instant Messaging client). Components are pre-configured to operate in a
673)     secure way, and it has very few dependencies on the installed operating
674)     system. It has therefore become one of the most easy to use, and popular,

675)     ways to use Tor on Windows.</p>
676)     <p>This project is to identify all of the traces left behind by
677)     using a Tor Browser Bundle on Windows, Mac OS X, or Linux.  Developing
678)     ways to stop, counter, or remove these traces is a final step.</p>
679)     <p>Students should be familiar with operating system analysis,

680)     application development on one or preferably all of Windows, Linux,

681)     and Mac OS X, and be comfortable with C/C++ and shell scripting.</p>
682)     <p>If you would like to help extend or do security auditing for
683)     TBB, please contact Erinn.</p>

684)     </li>
685)     

686)     <a id="firewallProbeTool"></a>
687)     <li>
688)     <b>Develop a fully automatic firewall-probing system</b>
689)     <br>
690)     Priority: <i>High</i>
691)     <br>
692)     Effort Level: <i>Medium to High</i>
693)     <br>
694)     Skill Level: <i>High</i>
695)     <br>
696)     Likely Mentors: <i>Robert Ransom, Nick, Jacob</i>
697)     <p>We would like to have a fully automatic firewall-probing system for
698)     blocking systems with no long-term state (i.e. firewalls that can
699)     examine each connection, but do not change their behaviour for future
700)     connections based on the traffic they have seen).</p>
701)     <p>Ideally, volunteers would only need to set up one or more test servers,
702)     and run the probe client program on a publicly accessible computer
703)     behind the firewall.</p>
704)     <p>The test tool should:</p>
705)     <ul>
706)     <li>generate packet captures on both ends (and send them out to the
707)         extent possible),</li>
708)     <li>cycle through all the SSL configurations we might want to test
709)         through a censorship device, and</li>
710)     <li>also test some other protocols to see whether they are allowed
711)         through the firewall (IMAP and other mail protocols, BitTorrent,
712)         DTLS, etc.).</li>
713)     </ul>
714)     </li>
715)     

716)     <a id="tailsStartMenu"></a>
717)     <li>
718)     <b>Custom GDM3 startup menu, aka. tails-greeter</b>
719)     <br>
720)     Priority: <i>High</i>
721)     <br>
722)     Effort Level: <i>Medium</i>
723)     <br>
724)     Skill Level: <i>Medium to High</i>
725)     <br>
726)     Likely Mentors: <i>intrigeri, anonym</i>

727)     <p>Several major upcoming Tails features need to gather user input at

728)     startup time: bridges support, persistence, MAC address anonymization,
729)     etc.</p>
730)     <p>Existing boot menus lack the graphical widgets and generally

731)     user-friendliness needed. Hence it was decided to implement Tails startup

732)     menu in GDM3: GDM3's default login/password prompt needs to be replaced
733)     with a custom GTK+ application hereby named tails-greeter that allows the
734)     user to provide any input necessary.</p>
735)     <p>Anyone undertaking this project should be familiar with GNU/Linux and
736)     application development; no other skill is required, apart of the ability
737)     to quickly find practical answers in APIs and documentation for many
738)     technologies she knows nothing about: this challenging coding project will
739)     indeed involve getting familiar with some modern GNU/Linux Desktop
740)     technologies such as D-Bus, GNOME and GConf. Python/GTK+ is probably the
741)     best suited language for the task.</p>

742)     <p>For more information see <a href="https://tails.boum.org/todo/boot_menu/">https://tails.boum.org/todo/boot_menu/</a></p>

743)     </li>
744) 

745)     <a id="orbot-torbutton"></a>
746)     <li>
747)     <b>TorButton for Mobile Firefox 4 or Custom Browser on Android</b>
748)     <br>
749)     Priority: <i>High</i>
750)     <br>
751)     Effort Level: <i>High</i>
752)     <br>
753)     Skill Level: <i>High</i>
754)     <br>
755)     Likely Mentors: <i>Nathan (n8fr8), Jake, Mike Perry</i>
756)     <p>Initial work has been done on implementing a proxy-setting add-on for
757)     Firefox on Android (see <a
758)     href="https://github.com/guardianproject/ProxyMob">ProxyMob</a>), but a
759)     full port of TorButton needs to be done (dependent upon Firefox 4 port of
760)     TorButton). The other approach is to implement a custom &quot;Tor
761)     Browser&quot; based on Firefox or Webkit browser. See <a
762)     href="http://code.google.com/p/torora/wiki/Android">Torora</a> for progress
763)     on this so far.</p>
764)     </li>
765)     
766)     <a id="orbot-userInterface"></a>
767)     <li>
768)     <b>Build a better user interface for Orbot</b>
769)     <br>
770)     Priority: <i>High</i>
771)     <br>
772)     Effort Level: <i>Medium</i>
773)     <br>
774)     Skill Level: <i>Medium</i>
775)     <br>
776)     Likely Mentors: <i>Nathan (n8fr8), Jake</i>
777)     <p>Improved home screen to show confirmation of connection (via a TorCheck
778)     API call), better statistics about data transferred (up/down), number of
779)     circuits connected, quality of connection and so on. The &quot;Tether
780)     Wifi&quot; Android application is a good model to follow in how it shows a
781)     realtime count of bytes transferred as well as notifications when wifi
782)     clients connect. In addition, better handling of Tor system and error
783)     messages would also be very helpful, include use of standard Android
784)     operating systems notifications. The addition of a wizard or tutorial
785)     walkthrough for novice users to explain to them exactly what is and what is
786)     not anonymized or protected would greatly improve the likelihood they will
787)     use Orbot correctly. All of this should work on the range of screens and
788)     device types now offered for Android, from 2&quot; phone to 10&quot;
789)     Tablet.</p>
790)     </li>
791)     

792)     <a id="resistCensorship"></a>

793)     <li>
794)     <b>Improving Tor's ability to resist censorship</b>

795)     <br>

796)     Priority: <i>Medium to High</i>

797)     <br>

798)     Effort Level: <i>Medium to High</i>

799)     <br>

800)     Skill Level: <i>High</i>

801)     <br>

802)     Likely Mentors: <i>Roger, Nick, Jake, Thomas</i>

803)     <p>The Tor 0.2.1.x series makes <a

804)     href="<svnprojects>design-paper/blocking.html">significant
805)     improvements</a> in resisting national and organizational censorship.
806)     But Tor still needs better mechanisms for some parts of its

807)     anti-censorship design.</p>
808)     <p>One huge category of work is adding features to our <a

809)     href="https://gitweb.torproject.org/bridgedb.git?a=tree">BridgeDB</a>

810)     service (Python). Tor aims to give out <a href="<page docs/bridges>">bridge
811)     relay addresses</a> to users that can't reach the Tor network
812)     directly, but there's an arms race between algorithms for distributing
813)     addresses and algorithms for gathering and blocking them. See <a

814)     href="<blog>bridge-distribution-strategies">our

815)     blog post on the topic</a> as an overview, and then look at <a

816)     href="https://lists.torproject.org/pipermail/tor-dev/2009-December/000666.html">Roger's
817)     or-dev post</a> from December 2009 for more recent thoughts &mdash; lots of

818)     design work remains.</p>
819)     <p>If you want to get more into the guts of Tor itself (C), a more minor problem

820)     we should address is that current Tors can only listen on a single
821)     address/port combination at a time. There's

822)     <a href="<specblob>proposals/118-multiple-orports.txt">a

823)     proposal to address this limitation</a> and allow clients to connect
824)     to any given Tor on multiple addresses and ports, but it needs more

825)     work.</p>
826)     <p>This project could involve a lot of research and design. One of the big

827)     challenges will be identifying and crafting approaches that can still
828)     resist an adversary even after the adversary knows the design, and

829)     then trading off censorship resistance with usability and
830)     robustness.</p>

831)     </li>
832)     

833)     <a id="stemPathsupport"></a>
834)     <li>
835)     <b>Stem PathSupport Capabilities</b>
836)     <br>
837)     Priority: <i>Medium</i>
838)     <br>
839)     Effort Level: <i>High</i>
840)     <br>
841)     Skill Level: <i>Medium</i>
842)     <br>
843)     Likely Mentors: <i>Damian (atagar)</i>
844)     <p><a
845)     href="https://trac.torproject.org/projects/tor/wiki/doc/stem">Stem</a> is a
846)     python controller library for tor. Like it's predecessor, <a
847)     href="#project-torctl">TorCtl</a>, it uses tor's <a
848)     href="https://gitweb.torproject.org/torspec.git/blob/HEAD:/control-spec.txt">control
849)     protocol</a> to help developers program against the tor process, enabling
850)     them to build things similar to <a href="#project-vidalia">Vidalia</a> and
851)     <a href="#project-arm">arm</a>.</p>
852)     
853)     <p>While TorCtl provided a fine first draft for this sort of functionality,
854)     it has not proved to be extensible nor maintainable. Stem is a rewrite of
855)     TorCtl with a heavy focus on testing, documentation, and providing a
856)     developer friendly API.</p>
857)     
858)     <p>At the moment stem is still very much incomplete, missing several pieces
859)     of functionality that TorCtl provides. This is a project to fix that by
860)     porting TorCtl's <a
861)     href="https://gitweb.torproject.org/pytorctl.git/blob/HEAD:/PathSupport.py">PathSupport
862)     module</a> to stem, writing tests for it, and migrate a couple clients to
863)     use it.</p>
864)     
865)     <p>PathSupport provides applications with programmatic control over how
866)     tor's circuits are built, for instance letting you exit from particular
867)     relays. This is used by projects like <a href="#project-torbel">TorBEL</a>,
868)     <a href="#project-torflow">the Bandwidth Scanners, and SoaT</a>.</p>
869)     
870)     <p>This project can be broken into three parts...</p>
871)     
872)     <ol style="list-style-type: decimal">
873)       <li><p>Look at PathSupport's clients to figure out how it is used and
874)       come up with the API that we will use for stem. Note that the goal if
875)       this project is <b>not</b> to simply copy PathSupport, but to make it
876)       better. This task would ideally be done as part of writing the GSoC
877)       application.</p></li>
878)       <li><p>Implement the PathSupport counterpart for stem. This should be
879)       done in an incremental fashion, writing the feature, tests, and going
880)       through a code review before moving on. I'll be pretty anal about making
881)       it as good as we can during these code reviews so plan for this to take a
882)       while. ;)</p></li>
883)       <li><p>The real test of the API that you've developed will come when we
884)       use it in some real applications. Try to migrate a TorCtl client or two
885)       to stem, filling in functionality that we're missing and improving our
886)       API as we discover issues. A particularly good client to start with would
887)       be TorBEL.</p></li>
888)     </ol>
889)     

890)     <a id="geoIPUpgrade"></a>
891)     <li>
892)     <b>Improve our GeoIP file format</b>
893)     <br>
894)     Priority: <i>Medium</i>
895)     <br>
896)     Effort Level: <i>Medium</i>
897)     <br>
898)     Skill Level: <i>Medium to High</i>
899)     <br>
900)     Likely Mentors: <i>Robert Ransom</i>
901)     <p>Currently, Tor bridges and relays read an entire IP->country database
902)     into memory from a text file during startup.  We would like to
903)     distribute this database and store it on disk in a much more compact

904)     form, and perform IP->country lookups on it in its on-disk format if
905)     possible.</p>

906)     <p>We have <a href='https://trac.torproject.org/projects/tor/ticket/2506'>a
907)     sketch of a design</a> for a moderately optimized format for IPv4 GeoIP
908)     data; this project will involve both implementing the IPv4 format and
909)     designing and implementing a format for IPv6 GeoIP data.</p>

910)     <!--<p>Since the core of this project is researching IPv6 GeoIP data and
911)     designing the IPv6 format, this is not likely to be a good GSoC
912)     project.</p>-->

913)     </li>
914)     

915)     <!--

916)     <a id="armClientMode"></a>

917)     <li>
918)     <b>Client Mode Use Cases for Arm</b>
919)     <br>
920)     Priority: <i>Medium</i>
921)     <br>
922)     Effort Level: <i>High</i>
923)     <br>
924)     Skill Level: <i>Medium</i>
925)     <br>

926)     Likely Mentors: <i>Damian (atagar)</i>

927)     <p><a href="<page projects/arm>">Arm</a> is a Tor command line status
928)     monitor on *nix environments (Linux, Mac, and BSD). It functions much like
929)     top does, giving a CLI overlay of Tor's bandwidth usage, connections,
930)     configuration, log, etc. Thus far its design has been geared for Tor relay
931)     operators. However, this doesn't need to be the case. This project would be
932)     to expand and simplify arm to make it useful for Tor's client users
933)     too.</p>
934)     
935)     <p>This would include UI design, experimenting, and a lot of python
936)     hacking. Here's some ideas for client functionality arm could provide:</p>
937)     
938)     <ul>
939)       <li>A panel for client connections, showing each hop of the user's
940)       circuits with the ISP, country, and jurisdiction where those relays
941)       reside. Other interesting information would be the circuit's latency, how
942)       long its been around, and its possible exit ports. Some of this will be
943)       pretty tricky and require some experimentation to figure out what
944)       information can be fetched safely (for instance, scraping rdns and whois
945)       lookups could give hints about a relay's ISP, but we'd need to do it on
946)       all Tor relays to avoid leaking our connections to the resolver).</li>
947)       
948)       <li>Options to let the user request new circuits (the &quot;New
949)       Identity&quot; feature in Vidalia), select the exit country, etc.</li>
950)       
951)       <li>A panel showing Internet application and if their connections are
952)       being routed through Tor or not (giving a warning if there's leaks).</li>
953)       
954)       <li>The status of the bridges we're configured to use (ie, are they up?).
955)       This would include adding control port functionality to Tor for <a
956)       href="https://trac.torproject.org/projects/tor/ticket/2068">ticket
957)       2068</a>.</li>
958)       
959)       <li>A one click option to set Tor to be a client, relay, or bridge. The
960)       goal would be to make it trivial for users to voluntarily contribute to
961)       the Tor network.</li>
962)       
963)       <li>Menus as an alternative to hotkeys to make the interface more
964)       intuitive and usable for beginners (<a
965)       href="http://gnosis.cx/publish/programming/charming_python_6.html">example</a>).</li>
966)       
967)       <li>Look at Vidalia and TorK for ideas and solicit input from the Tor community.</li>
968)     </ul>
969)     

970)     <p>
971)     More information is available in the following sections of arm's dev notes: <a href="https://trac.torproject.org/projects/tor/wiki/projects/arm#ConnectionListingExpansion">Connection Listing Expansion</a>, <a href="https://trac.torproject.org/projects/tor/wiki/projects/arm#CircuitDetails">Circuit Details</a>, and <a href="https://trac.torproject.org/projects/tor/wiki/projects/arm#ClientModeUseCases">Client Mode Use Cases</a>
972)     </p>

973)     </li>

974)     -->

975)     

976)     <a id="metricsSearch"></a>
977)     <li>
978)     <b>Searchable Tor descriptor and Metrics data archive</b>
979)     <br>
980)     Priority: <i>Medium</i>
981)     <br>
982)     Effort Level: <i>Medium</i>
983)     <br>
984)     Skill Level: <i>Medium</i>
985)     <br>
986)     Likely Mentors: <i>Karsten</i>
987)     <p>The <a href="https://metrics.torproject.org/data.html">Metrics data archive</a> of Tor relay descriptors and other Tor-related network data has grown to over 100G in size, bz2-compressed.  We have developed two search interfaces: the <a href="https://metrics.torproject.org/relay-search.html">relay search</a> finds relays by nickname, fingerprint, or IP address in a given month; <a href="https://metrics.torproject.org/exonerator-beta.html">ExoneraTor</a> finds whether a given IP address was a relay on a given day.</p>
988)     
989)     <p>We'd like to have a more general search application for Tor descriptors and metrics data.  There are more <a href="https://metrics.torproject.org/formats.html">descriptor types</a> that we'd like to include in the search.  The search application should handle most of them and understand some semantics like what's a timestamp, what's an IP address, and what's a link to another descriptor.  Users should then be able to search for arbitrary strings or limit their search to given time periods or IP address ranges.  Descriptors that reference other descriptors should contain links, and descriptors should be able to say from where they are linked.  The goal is to make the archive easily browsable.</p>
990)     
991)     <p>The search application shall be separate from the metrics website and shouldn't rely on the metrics website codebase.  The search application will contain hourly updated descriptor data from the metrics website via rsync.  Programming language and database system are not specified yet, though there's a slight preference for Python/Django and Postgres for maintenance reasons.  If there are good reasons to pick something else, e.g, some NoSQL variant or some search application framework, that's fine, too.  Further requirements are that lookups should be really fast and that changes to the search application can be implemented in reasonable time.</p>
992)     
993)     <p>Applications for this project should come with a design of the proposed search application, ideally with a proof-of-concept based on a subset of the available data to show that it will be able to handle the 100G+ of data.</p>
994)     

995)     <a id="unitTesting"></a>

996)     <li>
997)     <b>Improve our unit testing process</b>

998)     <br>

999)     Priority: <i>Medium</i>

1000)     <br>

1001)     Effort Level: <i>Medium</i>

1002)     <br>

1003)     Skill Level: <i>Medium</i>

1004)     <br>

1005)     Likely Mentors: <i>Nick, Erinn</i>

1006)     <p>Tor needs to be tested far more thoroughly. This is a
1007)     multi-part effort. To start with, our unit test coverage should
1008)     rise substantially, especially in the areas outside the utility
1009)     functions. This will require significant refactoring of some parts
1010)     of Tor, in order to dissociate as much logic as possible from
1011)     globals.</p>

1012)     <p>Additionally, we need to automate our performance testing. We've got

1013)     buildbot to automate our regular integration and compile testing already
1014)     (though we need somebody to set it up on Windows),
1015)     but we need to get our network simulation tests (as built in <a
1016)     href="https://svn.torproject.org/svn/torflow/trunk/README">TorFlow</a>)
1017)     updated for more recent versions of Tor, and designed to launch a test
1018)     network either on a single machine, or across several, so we can test

1019)     changes in performance on machines in different roles automatically.</p>

1020)     </li>
1021)     

1022)     <a id="simulateSlowConnections"></a>

1023)     <li>
1024)     <b>Simulator for slow Internet connections</b>

1025)     <br>

1026)     Priority: <i>Medium</i>

1027)     <br>

1028)     Effort Level: <i>Medium</i>

1029)     <br>

1030)     Skill Level: <i>Medium</i>

1031)     <br>

1032)     Likely Mentors: <i>Nick</i>

1033)     <p>

1034)     Many users of Tor have poor-quality Internet connections, giving low
1035)     bandwidth, high latency, and high packet loss/re-ordering. User
1036)     experience is that Tor reacts badly to these conditions, but it is
1037)     difficult to improve the situation without being able to repeat the
1038)     problems in the lab.

1039)     </p>
1040)     
1041)     <p>

1042)     This project would be to build a simulation environment which
1043)     replicates the poor connectivity so that the effect on Tor performance
1044)     can be measured. Other components would be a testing utility to
1045)     establish what are the properties of connections available, and to
1046)     measure the effect of performance-improving modifications to Tor.

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

1050)     The tools used would be up to the student, but dummynet (for FreeBSD)
1051)     and nistnet (for Linux) are two potential components on which this
1052)     project could be built. Students should be experienced with network
1053)     programming/debugging and TCP/IP, and preferably familiar with C and a
1054)     scripting language.

1055)     </p>

1056)     </li>
1057)     

1058)     <a id="torbuttonForThunderbird"></a>

1059)     <li>
1060)     <b>Torbutton equivalent for Thunderbird</b>

1061)     <br>

1062)     Priority: <i>Medium</i>

1063)     <br>

1064)     Effort Level: <i>High</i>

1065)     <br>

1066)     Skill Level: <i>High</i>

1067)     <br>

1068)     Likely Mentors: <i>Mike</i>

1069)     <p>

1070)     We're hearing from an increasing number of users that they want to use
1071)     Thunderbird with Tor. However, there are plenty of application-level
1072)     concerns, for example, by default Thunderbird will put your hostname in
1073)     the outgoing mail that it sends. At some point we should start a new
1074)     push to build a Thunderbird extension similar to Torbutton.

1075)     </p>

1076)     </li>
1077)     

1078)     <a id="usabilityTesting"></a>

1079)     <li>
1080)     <b>Usability testing of Tor</b>

1081)     <br>

1082)     Priority: <i>Medium</i>

1083)     <br>

1084)     Effort Level: <i>Medium</i>

1085)     <br>

1086)     Skill Level: <i>Low to Medium</i>

1087)     <br>

1088)     Likely Mentors: <i>Andrew</i>

1089)     <p>

1090)     Especially the browser bundle, ideally amongst our target demographic.
1091)     That would help a lot in knowing what needs to be done in terms of bug
1092)     fixes or new features. We get this informally at the moment, but a more
1093)     structured process would be better.

1094)     </p>

1095)     
1096)     <p>
1097)     Please note that since this isn't a coding project, it isn't suitable for
1098)     Google Summer of Code.
1099)     </p>

1100)     </li>

1101)     

1102)     <a id="tailsMetadataAnonymizing"></a>
1103)     <li>
1104)     <b>Meta-data anonymizing toolkit for file publication</b>
1105)     <br>
1106)     Priority: <i>Medium</i>
1107)     <br>
1108)     Effort Level: <i>Low to Medium</i>
1109)     <br>
1110)     Skill Level: <i>Low to Medium</i>
1111)     <br>
1112)     Likely Mentors: <i>intrigeri, anonym</i>

1113)     <p>Tor helps greatly in publishing files anonymously. However, much personal
1114)     information can be enclosed *inside* such published files' meta-data: GPS
1115)     coordinates, author's name and so on. Anyone who wants to anonymously

1116)     publish a file can thus far too easily de-anonymize herself.</p>

1117)     <p>A set of tools allowing users to easily inspect and clean up meta-data in files

1118)     would benefit Tor users, and would e.g. be shipped in Tails.</p>

1119)     <p>A graphical user interface is a must, but library and command-line
1120)     interfaces are most welcome so that future work can add support for

1121)     cleaning published files to various publishing tools, such as desktop

1122)     social networking clients and Web content management systems.</p>

1123)     <p>This project mostly consists of writing glue between the many existing
1124)     tools and libraries that provide read/write access to files' meta-data. An

1125)     extensible program design would probably be the best bet, so that support
1126)     for other kinds of files can easily be added later.</p>
1127)     <p>The meta-data cleaning toolkit would run at least on GNU/Linux;
1128)     additional Windows and/or Mac OS X support would be welcome. The tools used
1129)     would be up to the students. The detailed specification is ready and will
1130)     be published soon.</p>

1131)     </li>   
1132)  

1133)     <a id="tailsDebianLive"></a>
1134)     <li>
1135)     <b>Improve Debian Live support for persistence</b>
1136)     <br>
1137)     Priority: <i>Medium</i>
1138)     <br>
1139)     Effort Level: <i>Medium</i>
1140)     <br>
1141)     Skill Level: <i>Low to Medium</i>
1142)     <br>
1143)     Likely Mentors: <i>intrigeri, anonym</i>
1144)     <p>Data persistence is a somewhat tricky topic in a Live system context,

1145)     especially one such as Tails, which is explicitly designed to avoid

1146)     leaving any trace of its use.</p>
1147)     <p>Some real-life use cases, however, require some kind of data

1148)     persistence. To start with, Tails should (carefully) support persistence of

1149)     application-specific configurations (e.g. GnuPG keyring) and of a user

1150)     arbitrary data store. Note that persistence in Tails will always be opt-in

1151)     and require encrypted storage.</p>

1152)     <p>The backend work consists of improving Debian Live's existing

1153)     persistence features to make them suit the specific context of Tails. A trust

1154)     relationship is already established with upstream who is happy to merge our
1155)     changes. The codebase is not that small and much refactoring is needed, so
1156)     this really is a programming project rather than a fire'n'forget shell
1157)     script hack contest.</p>
1158)     <p>Anyone undertaking this project must be familiar with GNU/Linux, and
1159)     preferably with Debian. Being able to (quickly learn to) write clean and
1160)     safe programs in shell is also needed.</p>

1161)     <p>For more information, see <a href="https://tails.boum.org/todo/persistence/">https://tails.boum.org/todo/persistence/</a>.</p>

1162)     </li>

1163)     

1164)     <a id="torsocksForOSX"></a>

1165)     <li>
1166)     <b>Make torsocks/dsocks work on OS X</b>

1167)     <br>

1168)     Priority: <i>Medium</i>

1169)     <br>

1170)     Effort Level: <i>Medium</i>

1171)     <br>

1172)     Skill Level: <i>Medium</i>

1173)     <br>

1174)     Likely Mentors: <i>Robert Hogan</i>

1175)     <p>

1176)     <a href="https://code.google.com/p/torsocks/">Torsocks</a> and <a
1177)     href="https://code.google.com/p/dsocks/">dsocks</a> are wrappers that will

1178)     run applications, intercept their outgoing network connections, and push
1179)     those connections through Tor. The goal is to handle applications that
1180)     don't support proxies (or don't supporting them well). To get it right,
1181)     they need to intercept many system calls. The syscalls you need to
1182)     intercept on Linux differ dramatically from those on BSD. So Torsocks
1183)     works fine on Linux, dsocks works ok on BSD (though it may be less
1184)     maintained and thus might miss more syscalls), and nothing works well
1185)     on both. First, we should patch dsocks to use Tor's <i>mapaddress</i>
1186)     commands from the controller interface, so we don't waste a whole
1187)     round-trip inside Tor doing the resolve before connecting. Second,
1188)     we should make our <i>torify</i> script detect which of torsocks or
1189)     dsocks is installed, and call them appropriately. This probably means
1190)     unifying their interfaces, and might involve sharing code between them
1191)     or discarding one entirely.

1192)     </p>
1193)     </li>
1194)     

1195)     <a id="vidaliaStatusEventInterface"></a>

1196)     <li>
1197)     <b>Tor Controller Status Event Interface for Vidalia</b>
1198)     <br>
1199)     Priority: <i>Medium</i>
1200)     <br>
1201)     Effort Level: <i>Medium</i>
1202)     <br>
1203)     Skill Level: <i>Low to Medium</i>
1204)     <br>

1205)     Likely Mentors: <i>Tomás</i>

1206)     <p>There are a number of status changes inside Tor of which the user may need
1207)     to be informed. For example, if the user is trying to set up his Tor as a
1208)     relay and Tor decides that its ports are not reachable from outside
1209)     the user's network, we should alert the user. Currently, all the user
1210)     gets is a couple of log messages in Vidalia's 'message log' window, which they
1211)     likely never see since they don't receive a notification that something
1212)     has gone wrong. Even if the user does actually look at the message log,
1213)     most of the messages make little sense to the novice user.</p>
1214)     <p>Tor has the ability to inform Vidalia of many such status
1215)     changes, and we recently implemented support for a couple of these
1216)     events. Still, there are many more status events which the user should
1217)     be informed of, and we need a better UI for actually displaying them
1218)     to the user.</p>
1219)     <p>The goal of this project then is to design and implement a UI for
1220)     displaying Tor status events to the user. For example, we might put a
1221)     little badge on Vidalia's tray icon that alerts the user to new status
1222)     events they should look at. Double-clicking the icon could bring up a
1223)     dialog that summarizes recent status events in simple terms and maybe
1224)     suggests a remedy for any negative events if they can be corrected by
1225)     the user. Of course, this is just an example and one is free to
1226)     suggest another approach.</p>
1227)     <p>A person undertaking this project should have good UI design and layout
1228)     skills and some C++ development experience. Previous experience with Qt and
1229)     Qt's Designer will be very helpful, but are not required. Some
1230)     English writing ability will also be useful, since this project will
1231)     likely involve writing small amounts of help documentation that should
1232)     be understandable by non-technical users. Bonus points for some graphic
1233)     design/Photoshop fu, since we might want/need some shiny new icons too.</p>
1234)     </li>
1235)     

1236)     <a id="orbot-optimisation"></a>
1237)     <li>
1238)     <b>Core Tor mobile optimisation</b>
1239)     <br>
1240)     Priority: <i>Medium</i>
1241)     <br>
1242)     Effort Level: <i>Medium</i>
1243)     <br>
1244)     Skill Level: <i>High</i>
1245)     <br>
1246)     Likely Mentors: <i>Nathan (n8fr8), Jake</i>
1247)     <p>
1248)     The existing port of Tor to Android is basically a straight
1249)     cross-compile to Linux ARM. There has been no work done in looking at
1250)     possible optimizations of Tor within a mobile hardware environment or on
1251)     mobile networks. In addition, a number of additional Android OS APIs are
1252)     available (such as wireless network status) that could be taken
1253)     advantage of.
1254)     </p>
1255)     
1256)     <p>
1257)     It should be noted, that even without optimisation, Tor is handling the
1258)     mobile network environment very well, automatically detecting change in
1259)     IP addresses, opening circuits, etc, as the device switches from no
1260)     coverage to 2G, 3G or Wifi constantly as it changes position. However,
1261)     this observation of &quot;very well&quot;, is just based on user
1262)     experience, and not any detailed study of what exactly is happening, and
1263)     what threats might exist because of this constantly changing network state.
1264)     </p>
1265)     
1266)     <p>
1267)     Finally, the build process needs to be moved to the Android NDK from the
1268)     custom GCC toolchain we are now using, and compatibility with Android
1269)     2.3 and 3.x Honeycomb OS need to be verified.
1270)     </p>
1271)     
1272)     <p>
1273)     For more information see the <a
1274)     href="https://svn.torproject.org/svn/projects/android/trunk/Orbot/BUILD">Orbot
1275)     build documentation</a>.
1276)     </p>
1277)     </li>
1278)     
1279)     <a id="orbot-orlibAndOutreach"></a>
1280)     <li>
1281)     <b>Orbot integration library and community outreach</b>
1282)     <br>
1283)     Priority: <i>Medium</i>
1284)     <br>
1285)     Effort Level: <i>Low</i>
1286)     <br>
1287)     Skill Level: <i>Medium</i>
1288)     <br>
1289)     Likely Mentors: <i>Nathan (n8fr8)</i>
1290)     <p>
1291)     We need additional work on <a
1292)     href="https://github.com/guardianproject/orlib">ORLib</a>, our library for
1293)     use with third-party application to easily enable them to support
1294)     &quot;Torification&quot; on non-rooted devices (i.e. w/o transparent
1295)     proxying). This library includes a SOCKS client, a wrapper for the Apache
1296)     HTTPClient library, a utility class for detecting the state of Orbot
1297)     connectivity, and other relevant/useful things an Android app might need to
1298)     anonymize itself. This work would includes direct development of the
1299)     library, documentation, and sample code. Outreach or effort to implement
1300)     the library within other open-source apps is also needed.
1301)     </p>
1302)     </li>
1303)     

1304)     <a id="vidaliaNetworkMap"></a>

1305)     <li>
1306)     <b>An Improved and More Usable Network Map in Vidalia</b>
1307)     <br>
1308)     Priority: <i>Low to Medium</i>
1309)     <br>
1310)     Effort Level: <i>Medium</i>
1311)     <br>
1312)     Skill Level: <i>Medium</i>
1313)     <br>

1314)     Likely Mentors: <i>Tomás</i>

1315)     <p>
1316)     One of Vidalia's existing features is a network map that shows the user
1317)     the approximate geographic location of relays in the Tor network and
1318)     plots the paths the user's traffic takes as it is tunneled through the
1319)     Tor network. The map is currently not very interactive and has rather
1320)     poor graphics. Instead, we implemented KDE's Marble widget such
1321)     that it gives us a better quality map and enables improved interactivity,
1322)     such as allowing the user to click on individual relays or circuits to
1323)     display additional information. We want to add the ability
1324)     for users to click on a particular relay or a country containing one or
1325)     more Tor exit relays and say, "I want my connections to exit
1326)     from here."
1327)     </p>
1328)     
1329)     <p>
1330)     This project will first involve getting familiar with Vidalia
1331)     and the Marble widget's API. One will then integrate the widget
1332)     into Vidalia and customize Marble to be better suited for our application,
1333)     such as making circuits clickable, storing cached map data in Vidalia's
1334)     own data directory, and customizing some of the widget's dialogs.
1335)     </p>
1336)     
1337)     <p>
1338)     A person undertaking this project should have good C++ development
1339)     experience. Previous experience with Qt and CMake is helpful, but not
1340)     required.
1341)     </p>

1342)     </li>
1343)     

1344)     <!--

1345)     <a id="armGui"></a>
1346)     <li>
1347)     <b>GUI for Arm</b>
1348)     <br>
1349)     Priority: <i>Low</i>
1350)     <br>
1351)     Effort Level: <i>High</i>
1352)     <br>
1353)     Skill Level: <i>Medium</i>
1354)     <br>

1355)     Likely Mentors: <i>Damian (atagar)</i>

1356)     <p>
1357)     Arm has several unique features, some of the most interesting being its
1358)     connection listing (correlating netstat results against the Tor consensus)
1359)     and configuration editor (a quick method for editing Tor's config, with
1360)     information pulled from the control port and man page). However, since arm
1361)     is a command line controller it's of limited appeal to certain sets of
1362)     users. This project would be to build a GTK or Qt frontend for the
1363)     controller, providing similar features set but with a windowed interface.
1364)     </p>
1365)     
1366)     <p>
1367)     The vast majority of arm's more interesting functionality lies in its

1368)     backend <a href="https://gitweb.torproject.org/arm.git/tree/HEAD:/src/util">utilities</a>, so

1369)     there should be little to no work decoupling the CLI from its backend.
1370)     Instead, this project would mostly be UI hacking and experimentation,
1371)     trying different interfaces to find something that's elegant and simple,
1372)     but matches the information found in the current terminal application.
1373)     </p>
1374)     </li>

1375)     -->

1376)     

1377)     <li>
1378)     <b>Bring up new ideas!</b>

1379)     <br>

1380)     Don't like any of these? Look at the <a

1381)     href="/press/presskit/2008-12-19-roadmap-full.pdf">Tor development

1382)     roadmap</a> for more ideas, or just try out Tor, Vidalia, and Torbutton,
1383)     and find out what you think needs fixing.

1384)     Some of the <a href="<spectree>proposals">current proposals</a>

1385)     might also be short on developers.
1386)     </li>
1387)     
1388)     </ol>
1389)     
1390)     <a id="OtherCoding"></a>
1391)     <h2><a class="anchor" href="#OtherCoding">Other Coding and Design related ideas</a></h2>
1392)     <ol>
1393)     <li>Tor relays don't work well on Windows XP. On
1394)     Windows, Tor uses the standard <tt>select()</tt> system
1395)     call, which uses space in the non-page pool. This means
1396)     that a medium sized Tor relay will empty the non-page pool, <a

1397)     href="<wiki>doc/WindowsBufferProblems">causing

1398)     havoc and system crashes</a>. We should probably be using overlapped IO
1399)     instead. One solution would be to teach <a
1400)     href="http://www.monkey.org/~provos/libevent/">libevent</a> how to use
1401)     overlapped IO rather than select() on Windows, and then adapt Tor to
1402)     the new libevent interface. Christian King made a
1403)     <a href="https://svn.torproject.org/svn/libevent-urz/trunk/">good
1404)     start</a> on this in the summer of 2007.</li>
1405)     
1406)     <li>We need to actually start building our <a href="<page
1407)     docs/documentation>#DesignDoc">blocking-resistance design</a>. This involves
1408)     fleshing out the design, modifying many different pieces of Tor, adapting
1409)     <a href="<page projects/vidalia>">Vidalia</a> so it supports the
1410)     new features, and planning for deployment.</li>
1411)     
1412)     <li>We need a flexible simulator framework for studying end-to-end
1413)     traffic confirmation attacks. Many researchers have whipped up ad hoc
1414)     simulators to support their intuition either that the attacks work
1415)     really well or that some defense works great. Can we build a simulator
1416)     that's clearly documented and open enough that everybody knows it's
1417)     giving a reasonable answer? This will spur a lot of new research.
1418)     See the entry <a href="#Research">below</a> on confirmation attacks for
1419)     details on the research side of this task &mdash; who knows, when it's
1420)     done maybe you can help write a paper or three also.</li>
1421)     

1422)     <li>Tor 0.1.1.x and later include support for hardware crypto
1423)     accelerators via OpenSSL. It has been lightly tested and is
1424)     possibly very buggy.  We're looking for more rigorous testing,

1425)     performance analysis, and optimally, code fixes to OpenSSL and

1426)     Tor if needed.</li>

1427)     
1428)     <li>Perform a security analysis of Tor with <a

1429)     href="https://secure.wikimedia.org/wikipedia/en/wiki/Fuzz_testing">"fuzz"</a>. Determine

1430)     if there are good fuzzing libraries out there for what we want. Win fame by
1431)     getting credit when we put out a new release because of you!</li>
1432)     
1433)     <li>Tor uses TCP for transport and TLS for link
1434)     encryption. This is nice and simple, but it means all cells
1435)     on a link are delayed when a single packet gets dropped, and
1436)     it means we can only reasonably support TCP streams. We have a <a

1437)     href="<page docs/faq>#TransportIPnotTCP">list

1438)     of reasons why we haven't shifted to UDP transport</a>, but it would
1439)     be great to see that list get shorter. We also have a proposed <a

1440)     href="<specblob>proposals/100-tor-spec-udp.txt">specification

1441)     for Tor and
1442)     UDP</a> &mdash; please let us know what's wrong with it.</li>
1443)     
1444)     <li>We're not that far from having IPv6 support for destination addresses
1445)     (at exit nodes). If you care strongly about IPv6, that's probably the
1446)     first place to start.</li>
1447)     
1448)     <li>We need a way to generate the website diagrams (for example, the "How
1449)     Tor Works" pictures on the <a href="<page about/overview>">overview page</a>
1450)     from source, so we can translate them as UTF-8 text rather than edit
1451)     them by hand with Gimp. We might want to
1452)     integrate this as an wml file so translations are easy and images are
1453)     generated in multiple languages whenever we build the website.</li>
1454)     
1455)     <li>How can we make the various LiveCD/USB systems easier
1456)     to maintain, improve, and document?  One example is <a

1457)     href="https://tails.boum.org/">The Amnesic Incognito Live

1458)     System</a>.
1459)     </li>
1460)     
1461)     <li>
1462)     Another anti-censorship project is to try to make Tor
1463)     more scanning-resistant.  Right now, an adversary can identify <a

1464)     href="<specblob>proposals/125-bridges.txt">Tor bridges</a>

1465)     just by trying to connect to them, following the Tor protocol,
1466)     and seeing if they respond.  To solve this, bridges could <a
1467)     href="<svnprojects>design-paper/blocking.html#tth_sEc9.3">act like
1468)     webservers</a> (HTTP or HTTPS) when contacted by port-scanning tools,
1469)     and not act like bridges until the user provides a bridge-specific key.
1470)     To start, check out Shane Pope's <a
1471)     href="http://dl.dropbox.com/u/37735/index.html">thesis and prototype</a>.
1472)     </li>
1473)     
1474)     </ol>
1475)     
1476)     <a id="Research"></a>
1477)     <h2><a class="anchor" href="#Research">Research</a></h2>
1478)     <ol>
1479)     <li>The "end-to-end traffic confirmation attack":
1480)     by watching traffic at Alice and at Bob, we can <a
1481)     href="http://freehaven.net/anonbib/#danezis:pet2004">compare
1482)     traffic signatures and become convinced that we're watching the same
1483)     stream</a>. So far Tor accepts this as a fact of life and assumes this
1484)     attack is trivial in all cases. First of all, is that actually true? How
1485)     much traffic of what sort of distribution is needed before the adversary
1486)     is confident he has won? Are there scenarios (e.g. not transmitting much)
1487)     that slow down the attack? Do some traffic padding or traffic shaping
1488)     schemes work better than others?</li>
1489)     <li>A related question is: Does running a relay/bridge provide additional
1490)     protection against these timing attacks? Can an external adversary that can't
1491)     see inside TLS links still recognize individual streams reliably?
1492)     Does the amount of traffic carried degrade this ability any? What if the
1493)     client-relay deliberately delayed upstream relayed traffic to create a queue
1494)     that could be used to mimic timings of client downstream traffic to make it
1495)     look like it was also relayed? This same queue could also be used for masking
1496)     timings in client upstream traffic with the techniques from <a
1497)     href="http://www.freehaven.net/anonbib/#ShWa-Timing06">adaptive padding</a>,
1498)     but without the need for additional traffic. Would such an interleaving of
1499)     client upstream traffic obscure timings for external adversaries? Would the
1500)     strategies need to be adjusted for asymmetric links? For example, on
1501)     asymmetric links, is it actually possible to differentiate client traffic from
1502)     natural bursts due to their asymmetric capacity? Or is it easier than
1503)     symmetric links for some other reason?</li>
1504)     <li>Repeat Murdoch and Danezis's <a
1505)     href="http://www.cl.cam.ac.uk/~sjm217/projects/anon/#torta">attack from
1506)     Oakland 05</a> on the current Tor network. See if you can learn why it
1507)     works well on some nodes and not well on others. (My theory is that the
1508)     fast nodes with spare capacity resist the attack better.) If that's true,
1509)     then experiment with the RelayBandwidthRate and RelayBandwidthBurst
1510)     options to run a relay that is used as a client while relaying the
1511)     attacker's traffic: as we crank down the RelayBandwidthRate, does the
1512)     attack get harder? What's the right ratio of RelayBandwidthRate to
1513)     actually capacity? Or is it a ratio at all? While we're at it, does a
1514)     much larger set of candidate relays increase the false positive rate
1515)     or other complexity for the attack? (The Tor network is now almost two
1516)     orders of magnitude larger than it was when they wrote their paper.) Be
1517)     sure to read <a href="http://freehaven.net/anonbib/#clog-the-queue">Don't
1518)     Clog the Queue</a> too.</li>
1519)     <li>The "routing zones attack": most of the literature thinks of
1520)     the network path between Alice and her entry node (and between the
1521)     exit node and Bob) as a single link on some graph. In practice,
1522)     though, the path traverses many autonomous systems (ASes), and <a
1523)     href="http://freehaven.net/anonbib/#feamster:wpes2004">it's not uncommon
1524)     that the same AS appears on both the entry path and the exit path</a>.
1525)     Unfortunately, to accurately predict whether a given Alice, entry,
1526)     exit, Bob quad will be dangerous, we need to download an entire Internet
1527)     routing zone and perform expensive operations on it. Are there practical
1528)     approximations, such as avoiding IP addresses in the same /8 network?</li>
1529)     <li>Other research questions regarding geographic diversity consider
1530)     the tradeoff between choosing an efficient circuit and choosing a random
1531)     circuit. Look at Stephen Rollyson's <a
1532)     href="http://swiki.cc.gatech.edu:8080/ugResearch/uploads/7/ImprovingTor.pdf">position
1533)     paper</a> on how to discard particularly slow choices without hurting
1534)     anonymity "too much". This line of reasoning needs more work and more
1535)     thinking, but it looks very promising.</li>
1536)     <li>Tor doesn't work very well when relays have asymmetric bandwidth
1537)     (e.g. cable or DSL). Because Tor has separate TCP connections between
1538)     each hop, if the incoming bytes are arriving just fine and the outgoing
1539)     bytes are all getting dropped on the floor, the TCP push-back mechanisms
1540)     don't really transmit this information back to the incoming streams.
1541)     Perhaps Tor should detect when it's dropping a lot of outgoing packets,
1542)     and rate-limit incoming streams to regulate this itself? I can imagine
1543)     a build-up and drop-off scheme where we pick a conservative rate-limit,
1544)     slowly increase it until we get lost packets, back off, repeat. We
1545)     need somebody who's good with networks to simulate this and help design
1546)     solutions; and/or we need to understand the extent of the performance
1547)     degradation, and use this as motivation to reconsider UDP transport.</li>
1548)     <li>A related topic is congestion control. Is our
1549)     current design sufficient once we have heavy use? Maybe
1550)     we should experiment with variable-sized windows rather
1551)     than fixed-size windows? That seemed to go well in an <a
1552)     href="http://www.psc.edu/networking/projects/hpn-ssh/theory.php">ssh
1553)     throughput experiment</a>. We'll need to measure and tweak, and maybe
1554)     overhaul if the results are good.</li>
1555)     <li>Our censorship-resistance goals include preventing
1556)     an attacker who's looking at Tor traffic on the wire from <a
1557)     href="<svnprojects>design-paper/blocking.html#sec:network-fingerprint">distinguishing
1558)     it from normal SSL traffic</a>. Obviously we can't achieve perfect
1559)     steganography and still remain usable, but for a first step we'd like to
1560)     block any attacks that can win by observing only a few packets. One of
1561)     the remaining attacks we haven't examined much is that Tor cells are 512
1562)     bytes, so the traffic on the wire may well be a multiple of 512 bytes.
1563)     How much does the batching and overhead in TLS records blur this on the
1564)     wire? Do different buffer flushing strategies in Tor affect this? Could
1565)     a bit of padding help a lot, or is this an attack we must accept?</li>
1566)     <li>Tor circuits are built one hop at a time, so in theory we have the
1567)     ability to make some streams exit from the second hop, some from the
1568)     third, and so on. This seems nice because it breaks up the set of exiting
1569)     streams that a given relay can see. But if we want each stream to be safe,
1570)     the "shortest" path should be at least 3 hops long by our current logic, so
1571)     the rest will be even longer. We need to examine this performance / security
1572)     tradeoff.</li>
1573)     <li>It's not that hard to DoS Tor relays or directory authorities. Are client
1574)     puzzles the right answer? What other practical approaches are there? Bonus
1575)     if they're backward-compatible with the current Tor protocol.</li>
1576)     <li>Programs like <a

1577)     href="<page torbutton/index>">Torbutton</a> aim to hide