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r24791: {} my abstract for the crypto 2011 talk (in projects/articles: . crypto2011)
by Roger Dingledine 28 May '11

28 May '11

Author: arma Date: 2011-05-28 07:16:03 +0000 (Sat, 28 May 2011) New Revision: 24791 Added: projects/articles/crypto2011/ projects/articles/crypto2011/crypto2011-tor.bib projects/articles/crypto2011/crypto2011-tor.tex projects/articles/crypto2011/direct-users-2011-04-01-300-eg-2010-12-01.png projects/articles/crypto2011/direct-users-2011-04-01-300-ir-2010-12-01.png projects/articles/crypto2011/direct-users-2011-04-01-300-ly-2010-12-01.png projects/articles/crypto2011/direct-users-2011-04-01-300-sa-2010-09-01.png projects/articles/crypto2011/direct-users-2011-04-01-300-tn-2010-12-01.png Log: my abstract for the crypto 2011 talk Added: projects/articles/crypto2011/crypto2011-tor.bib =================================================================== --- projects/articles/crypto2011/crypto2011-tor.bib (rev 0) +++ projects/articles/crypto2011/crypto2011-tor.bib 2011-05-28 07:16:03 UTC (rev 24791) @@ -0,0 +1,154 @@ +@inproceedings{dingledine2004tor, + author = {Roger Dingledine and Nick Mathewson and Paul Syverson}, + title = {Tor: The Second-Generation Onion Router}, + booktitle = {Proceedings of the 13th USENIX Security Symposium}, + year = {2004}, + month = {August}, + pages = {303--320}, +} + +@inproceedings{mccoy2008shining, + title = {Shining Light in Dark Places: Understanding the {Tor} Network}, + author = {Damon McCoy and Kevin Bauer and Dirk Grunwald and Tadayoshi + Kohno and Douglas Sicker}, + booktitle = {Proceedings of the Eighth Symposium on Privacy Enhancing + Technologies (PETS 2008)}, + year = {2008}, + month = {July}, + address = {Leuven, Belgium}, + pages = {63--76}, + editor = {Nikita Borisov and Ian Goldberg}, + publisher = {Springer}, + series = {Lecture Notes in Computer Science}, + volume = {5134}, +} + +@inproceedings{differential, + title = {Differential Privacy}, + author = {Cynthia Dwork}, + booktitle = {33rd International Colloquium on Automata, Languages +and Programming (ICALP)}, + year = {2006}, + month = {July}, + address = {Venice, Italy}, + pages = {1--12}, + publisher = {Springer}, + series = {Lecture Notes in Computer Science}, + volume = {4052}, +} + +@techreport{loesing2009measuring, + title = {Measuring the {Tor} Network from Public Directory Information}, + author = {Karsten Loesing}, + institution = {2nd Hot Topics in Privacy Enhancing Technologies (HotPETs + 2009)}, + year = {2009}, + month = {August}, + address = {Seattle, WA, USA}, +} + +@inproceedings{loesing2008performance, + author = {Karsten Loesing and Werner Sandmann and Christian Wilms and Guido Wirtz}, + title = {Performance Measurements and Statistics of {Tor} Hidden Services}, + booktitle = {Proceedings of the International Symposium on Applications and the Internet (SAINT 2008)}, + month = {July}, + year = {2008}, + address = {Turku, Finland}, + publisher = {IEEE Computer Society} +} + +@inproceedings{lenhard2009performance, + title = {Performance Measurements of {Tor} Hidden Services in Low-Bandwidth Access Networks}, + author = {J{\"o}rg Lenhard and Karsten Loesing and Guido Wirtz}, + booktitle = {Proceedings of the 7th International Conference on + Applied Cryptography and Network Security (ACNS 09), Paris-Rocquencourt, France}, + month = {June}, + year = {2009}, +} + +@inproceedings{wendolsky2007performance, + title = {Performance Comparison of Low-Latency Anonymisation Services from a User Perspective}, + author = {Rolf Wendolsky and Dominik Herrmann and Hannes Federrath}, + booktitle = {Proceedings of the Seventh Symposium on Privacy Enhancing Technologies (PET 2007)}, + pages = {233--253}, + year = {2007}, + month = {June}, + series = {Lecture Notes in Computer Science}, + publisher = {Springer}, + editor = {Nikita Borisov and Philippe Golle}, + volume = {4776}, +} + +@manual{tor2009dirspec, + author = {The Tor Project}, + title = {Tor directory protocol, version 3}, + year = {2009}, + note = {\url{https://git.torproject.org/checkout/tor/master/doc/spec/dir-spec.txt}}, +} + +@manual{bridges-spec, + author = {The Tor Project}, + title = {Tor bridges specification}, + year = {2009}, + note = {\url{https://git.torproject.org/checkout/tor/master/doc/spec/bridges-spec.txt}}, +} + +@inproceedings{murdoch-pet2007, + title = {Sampled Traffic Analysis by {I}nternet-Exchange-Level Adversaries}, + author = {Steven J. Murdoch and Piotr Zieli{\'n}ski}, + booktitle = {Proceedings of the Seventh Workshop on Privacy Enhancing Technologies (PET 2007)}, + year = {2007}, + month = {June}, + address = {Ottawa, Canada}, + editor = {Nikita Borisov and Philippe Golle}, + publisher = {Springer}, + series = {LNCS 4776}, +} + +@inproceedings{hs-attack06, + title = {Locating Hidden Servers}, + author = {Lasse {\O}verlier and Paul Syverson}, + booktitle = {Proceedings of the 2006 IEEE Symposium on Security and Privacy}, + year = {2006}, + month = {May}, + publisher = {IEEE CS}, + www_pdf_url = {http://www.onion-router.net/Publications/locating-hidden-servers.pdf}, + www_section = {Traffic analysis}, +} + +@misc{colorado-irb-response, + author = {Damon McCoy and Kevin Bauer and Dirk Grunwald and Tadayoshi Kohno and Douglas Sicker}, + title = {Response to Tor Study}, + note = {\url{http://systems.cs.colorado.edu/mediawiki/index.php/Response_To_Tor_Study}}, +} + +@misc{tor-legal-faq, + key = "Tor-legal-faq", + author = "{Electronic Frontier Foundation}", + title = "Tor: Legal {FAQ} for {T}or Server Operators", + howpublished = {\url{https://www.torproject.org/eff/tor-legal-faq.html}} +} + +@inproceedings{wecsr10measuring-tor, + title = {A Case Study on Measuring Statistical Data in the {T}or Anonymity Network}, + author = {Karsten Loesing and Steven J. Murdoch and Roger Dingledine}, + booktitle = {Proceedings of the Workshop on Ethics in Computer Security Research (WECSR 2010)}, + year = {2010}, + month = {January}, + address = {Tenerife, Canary Islands, Spain}, + publisher = {Springer}, + series = {LNCS 6054}, + editor = {Sven Dietrich}, + howpublished = {\url{https://metrics.torproject.org/papers/wecsr10.pdf}}, +} + +@techreport{tor-blocking, + title = {Design of a blocking-resistant anonymity system}, + author = {Roger Dingledine and Nick Mathewson}, + institution = {The Tor Project}, + number = {2006-1}, + year = {2006}, + month = {November}, + howpublished = {\url{https://svn.torproject.org/svn/projects/design-paper/blocking.pdf}}, +} + Property changes on: projects/articles/crypto2011/crypto2011-tor.bib ___________________________________________________________________ Added: svn:executable + * Added: projects/articles/crypto2011/crypto2011-tor.tex =================================================================== --- projects/articles/crypto2011/crypto2011-tor.tex (rev 0) +++ projects/articles/crypto2011/crypto2011-tor.tex 2011-05-28 07:16:03 UTC (rev 24791) @@ -0,0 +1,113 @@ +\documentclass{llncs} +\usepackage[cmex10]{amsmath} +\usepackage{subfigure} +\usepackage[pdftex]{graphicx} +\usepackage{graphics} +\usepackage{color} +\pagestyle{empty} + +%\usepackage[pdftex,% +% breaklinks=true,% +% colorlinks=true,% +% linkcolor=black,% +% citecolor=black,% +% urlcolor=black,% +% bookmarks=false,% +% pdfpagemode=UseNone,% +%]{hyperref} + +\begin{document} +\title{Tor and circumvention: lessons learned\\ +(Abstract to go with invited talk)} +\author{Roger Dingledine} +\institute{The Tor Project} +\maketitle + +Tor is a free-software anonymizing overlay network that helps people +around the world use the Internet in safety. Tor's 2500 volunteer relays +carry almost 10Gb/s of traffic for several hundred thousand users each day. + +While many in the +research community know Tor as the primary fielded system in the anonymous +communications literature~\cite{dingledine2004tor}, Tor has also played a +central role in recent +research on \emph{blocking resistance}. That is, even if an anonymity +system provides +great anonymity, a government censor can render it moot by simply +blocking the relays. In recent years we streamlined Tor's +network communications to look more like ordinary SSL, and we introduced +``bridge relays'' that are harder for an attacker to find and block than +Tor's public relays~\cite{tor-blocking}. + +Tor played a key role in several Middle Eastern countries in early +2011. In this talk I'll walk the audience through how Iran used +its Nokia DPI boxes to filter SSL flows that used Tor's original Diffie-Hellman +parameter $p$; the surge in Tor traffic when Egypt blocked Facebook and +the flatline when they unplugged the net; the continued bad news for +Libya's Internet; and an intriguing trend in Saudi Arabia. I'll also +cover current trends in China and Tunisia (not pictured). + +\begin{figure}[h] +\begin{minipage}{0.495\textwidth} +\includegraphics[width=\linewidth]{direct-users-2011-04-01-300-ir-2010-12-01.png} +\end{minipage} +\begin{minipage}{0.495\textwidth} +\includegraphics[width=\linewidth]{direct-users-2011-04-01-300-eg-2010-12-01.png} +\end{minipage} +\begin{minipage}{0.495\textwidth} +\includegraphics[width=\linewidth]{direct-users-2011-04-01-300-ly-2010-12-01.png} +\end{minipage} +\begin{minipage}{0.495\textwidth} +\includegraphics[width=\linewidth]{direct-users-2011-04-01-300-sa-2010-09-01.png} +\end{minipage} +\caption{Estimates of daily Tor clients connecting from each country} +\end{figure} + +The data for these user graphs, along with historical Tor network +data and ongoing performance statistics, are all available at +https://metrics.torproject.org/. Our WECSR'10 +paper~\cite{wecsr10measuring-tor} explains our +aggregation techniques and why we think they're safe---we'd love for you +to show us that we're wrong. Further, if you're working on Tor-related +research, please talk to us (https://torproject.org/research) +so we can explain what's available and help interpret your results. + +\subsection*{Some open questions from the anonymity field} + +Here are a few examples of open anonymity and blocking-resistance +problems: + +1) How effective is the traffic correlation attack really? Tor's threat +model assumes that an adversary who can see a traffic flow into the Tor +network and the corresponding flow out of the Tor network can correlate +them with high probability and low false positives. Recent results from +Steven Murdoch~\cite{murdoch-pet2007} show confirmation attacks even when both +sides only see a small sample of traffic on each side. But how quick +can the attack actually be in practice, using how little traffic? Are +there effective padding schemes to make correlation less effective? + +2) For various diversity metrics (like entropy), how has the diversity +of the Tor network changed over time? How robust is it to change or +attack?{\footnote{https://blog.torproject.org/blog/research-problem-measuring-safety-tor-network}} + +3) How can we automatically recognize blocking events---when Tor relays +are censored at a firewall by destination address or by traffic flow +characteristics? + +4) Clients who are censored from the public Tor relays can use private +addresses to ``bridge'' into the public Tor network. What strategies +should we use to give out these addresses such that legitimate users +get enough addresses but adversaries can't learn too many? + +5) How can we make it hard for censors to recognize Tor traffic flows by +content (e.g.\ distinguishing Tor's handshake from other expected protocols) +and by traffic characteristics (packet size, volume, and timing)? We need +\emph{obfuscation} metrics to let us anticipate which protocols will +blend in better with background traffic or otherwise defeat deep packet +inspection (DPI) algorithms. + +\bibliographystyle{plain} \bibliography{crypto2011-tor} +\end{document} + +\end{document} + Added: projects/articles/crypto2011/direct-users-2011-04-01-300-eg-2010-12-01.png =================================================================== (Binary files differ) Property changes on: projects/articles/crypto2011/direct-users-2011-04-01-300-eg-2010-12-01.png ___________________________________________________________________ Added: svn:mime-type + application/octet-stream Added: projects/articles/crypto2011/direct-users-2011-04-01-300-ir-2010-12-01.png =================================================================== (Binary files differ) Property changes on: projects/articles/crypto2011/direct-users-2011-04-01-300-ir-2010-12-01.png ___________________________________________________________________ Added: svn:mime-type + application/octet-stream Added: projects/articles/crypto2011/direct-users-2011-04-01-300-ly-2010-12-01.png =================================================================== (Binary files differ) Property changes on: projects/articles/crypto2011/direct-users-2011-04-01-300-ly-2010-12-01.png ___________________________________________________________________ Added: svn:mime-type + application/octet-stream Added: projects/articles/crypto2011/direct-users-2011-04-01-300-sa-2010-09-01.png =================================================================== (Binary files differ) Property changes on: projects/articles/crypto2011/direct-users-2011-04-01-300-sa-2010-09-01.png ___________________________________________________________________ Added: svn:mime-type + application/octet-stream Added: projects/articles/crypto2011/direct-users-2011-04-01-300-tn-2010-12-01.png =================================================================== (Binary files differ) Property changes on: projects/articles/crypto2011/direct-users-2011-04-01-300-tn-2010-12-01.png ___________________________________________________________________ Added: svn:mime-type + application/octet-stream

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[tor/master] Merge remote-tracking branch 'origin/maint-0.2.1' into maint-0.2.2
by nickm＠torproject.org 28 May '11

28 May '11

commit 1f18b5a5d532449f46a9c4b74d188870ea56d813 Merge: c319949 f43aceb Author: Nick Mathewson <nickm(a)torproject.org> Date: Sat May 28 02:13:14 2011 -0400 Merge remote-tracking branch 'origin/maint-0.2.1' into maint-0.2.2 changes/bug2574 | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-)

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[tor/master] Fix typo in changes/bug2574. Thanks, rransom
by nickm＠torproject.org 28 May '11

28 May '11

commit f43aceb0f1b10d71d2e99e323668ac35327e286b Author: Nick Mathewson <nickm(a)torproject.org> Date: Sat May 28 02:13:04 2011 -0400 Fix typo in changes/bug2574. Thanks, rransom --- changes/bug2574 | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/changes/bug2574 b/changes/bug2574 index 32f4ae4..5cf2dae 100644 --- a/changes/bug2574 +++ b/changes/bug2574 @@ -1,2 +1,3 @@ o Minor features: - - Allow nameserves with IPv6 address. Fixes bug 2574. + - Allow nameservers with IPv6 address. Fixes bug 2574. +

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[tor/master] Merge remote-tracking branch 'origin/maint-0.2.2'
by nickm＠torproject.org 28 May '11

28 May '11

commit e676db656da1c3911f0667faa4fd2396db1c9e8f Merge: 285cf99 1f18b5a Author: Nick Mathewson <nickm(a)torproject.org> Date: Sat May 28 02:13:25 2011 -0400 Merge remote-tracking branch 'origin/maint-0.2.2' changes/bug2574 | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-)

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[tor/maint-0.2.2] Fix typo in changes/bug2574. Thanks, rransom
by nickm＠torproject.org 28 May '11

28 May '11

commit f43aceb0f1b10d71d2e99e323668ac35327e286b Author: Nick Mathewson <nickm(a)torproject.org> Date: Sat May 28 02:13:04 2011 -0400 Fix typo in changes/bug2574. Thanks, rransom --- changes/bug2574 | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/changes/bug2574 b/changes/bug2574 index 32f4ae4..5cf2dae 100644 --- a/changes/bug2574 +++ b/changes/bug2574 @@ -1,2 +1,3 @@ o Minor features: - - Allow nameserves with IPv6 address. Fixes bug 2574. + - Allow nameservers with IPv6 address. Fixes bug 2574. +

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[tor/maint-0.2.2] Merge remote-tracking branch 'origin/maint-0.2.1' into maint-0.2.2
by nickm＠torproject.org 28 May '11

28 May '11

commit 1f18b5a5d532449f46a9c4b74d188870ea56d813 Merge: c319949 f43aceb Author: Nick Mathewson <nickm(a)torproject.org> Date: Sat May 28 02:13:14 2011 -0400 Merge remote-tracking branch 'origin/maint-0.2.1' into maint-0.2.2 changes/bug2574 | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-)

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[tor/maint-0.2.1] Fix typo in changes/bug2574. Thanks, rransom
by nickm＠torproject.org 28 May '11

28 May '11

commit f43aceb0f1b10d71d2e99e323668ac35327e286b Author: Nick Mathewson <nickm(a)torproject.org> Date: Sat May 28 02:13:04 2011 -0400 Fix typo in changes/bug2574. Thanks, rransom --- changes/bug2574 | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/changes/bug2574 b/changes/bug2574 index 32f4ae4..5cf2dae 100644 --- a/changes/bug2574 +++ b/changes/bug2574 @@ -1,2 +1,3 @@ o Minor features: - - Allow nameserves with IPv6 address. Fixes bug 2574. + - Allow nameservers with IPv6 address. Fixes bug 2574. +

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[tor/master] Merge branch 'bug2574' into maint-0.2.1
by nickm＠torproject.org 28 May '11

28 May '11

commit ee72557d528a846661d4d1d794c127de8c3ef1eb Merge: 0d94f78 be76850 Author: Nick Mathewson <nickm(a)torproject.org> Date: Sat May 28 02:07:48 2011 -0400 Merge branch 'bug2574' into maint-0.2.1 changes/bug2574 | 2 ++ src/or/eventdns.c | 2 +- 2 files changed, 3 insertions(+), 1 deletions(-)

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[tor/master] Work correctly if your nameserver is ::1
by nickm＠torproject.org 28 May '11

28 May '11

commit be76850995f337337dd94be66a9f03b35d8b1412 Author: Nick Mathewson <nickm(a)torproject.org> Date: Mon May 23 17:42:38 2011 -0400 Work correctly if your nameserver is ::1 We had all the code in place to handle this right... except that we were unconditionally opening a PF_INET socket instead of looking at sa_family. Ow. Fixes bug 2574; not a bugfix on any particular version, since this never worked before. --- changes/bug2574 | 2 ++ src/or/eventdns.c | 2 +- 2 files changed, 3 insertions(+), 1 deletions(-) diff --git a/changes/bug2574 b/changes/bug2574 new file mode 100644 index 0000000..32f4ae4 --- /dev/null +++ b/changes/bug2574 @@ -0,0 +1,2 @@ + o Minor features: + - Allow nameserves with IPv6 address. Fixes bug 2574. diff --git a/src/or/eventdns.c b/src/or/eventdns.c index 2777f90..adab22b 100644 --- a/src/or/eventdns.c +++ b/src/or/eventdns.c @@ -2320,7 +2320,7 @@ _evdns_nameserver_add_impl(const struct sockaddr *address, memset(ns, 0, sizeof(struct nameserver)); ns->timeout_event_deleted = __LINE__; - ns->socket = socket(PF_INET, SOCK_DGRAM, 0); + ns->socket = socket(address->sa_family, SOCK_DGRAM, 0); if (ns->socket < 0) { err = 1; goto out1; } #ifdef WIN32 {

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[tor/master] Merge remote-tracking branch 'origin/maint-0.2.1' into maint-0.2.2
by nickm＠torproject.org 28 May '11

28 May '11

commit c3199495503930e33e7370d6c364b2b8b35844f4 Merge: a5232e0 ee72557 Author: Nick Mathewson <nickm(a)torproject.org> Date: Sat May 28 02:08:39 2011 -0400 Merge remote-tracking branch 'origin/maint-0.2.1' into maint-0.2.2 changes/bug2574 | 2 ++ src/or/eventdns.c | 2 +- 2 files changed, 3 insertions(+), 1 deletions(-) diff --cc src/or/eventdns.c index b7cc292,1d93ae0..4753429 --- a/src/or/eventdns.c +++ b/src/or/eventdns.c @@@ -2288,10 -2318,9 +2288,10 @@@ _evdns_nameserver_add_impl(const struc if (!ns) return -1; memset(ns, 0, sizeof(struct nameserver)); - ns->timeout_event_deleted = __LINE__; + + evtimer_set(&ns->timeout_event, nameserver_prod_callback, ns); - ns->socket = socket(PF_INET, SOCK_DGRAM, 0); + ns->socket = socket(address->sa_family, SOCK_DGRAM, 0); if (ns->socket < 0) { err = 1; goto out1; } #ifdef WIN32 {

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