November 16, 2012

i’m in ur protocolz, jammin ur cellphonez

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Krish Eswaran sent me a story about how a group at Virgina Tech described how LTE networks are susceptible to a certain kind of jamming strategy:

“An example strategy would be to target specific control or synchronization signals, in order to increase the geographic range of the jammer and better avoid detection,” the Wireless @ Virginia Tech research group said in a filing (PDF) submitted to the National Telecommunications and Information Administration. “The availability of low-cost and easy to use software-defined radios makes this threat even more realistic.”

Color me unsurprised! For my PhD, I studied arbitrarily varying channels (AVCs), which are information-theoretic models for communication against adversarial interference. There are a couple of design insights one can distill from considering the AVC model:

  • Separating protocol and payload makes schemes susceptible to spoofing.
  • Lack of synchronization/coordination between sender and receiver can be a real problem in adversarial settings.

Here we have a case where the protocol is easy to spoof/disrupt, essentially because the control information in unprotected.

This separation between control information and payload is often suboptimal in other senses. See, for example, Tchamkerten, Chandar and Wornell.

 

October 31, 2012

DIMACS Workshop on Information-Theoretic Network Security

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At DIMACS, I got a notice about a workshop here that is coming up in November with a deadline ofr November 5 to register: the DIMACS Workshop on Information-Theoretic Network Security organized by Yingbin Liang and Prakash Narayan. Should be worth checking out — they have a nice slate of talks.

If you do come though, don’t stay at the Holiday Inn — go for The Heldrich or a Hyatt or something that is anywhere near walking distance to restaurants or something. I think I almost got run over going to Walgreens yesterday in this land of strip malls…

 

October 2, 2012

Sita tries to send a message to Rama using a digital certificate

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Via Erin (via Bruce Schneier’s blog), I found out about S. Parthasarathy‘s proposal to replace Alice and Bob with Sita and Rama. I have been known to use Alice and Bob on occasion (unlike some people I find the anthropomorphizing to be good, on the balance), but perhaps I should develop some cultural pride and make the switch to “a smarter alternative to these characters.” According to Parthasarathy, there is greater literary relevance to the scenario where Sita wants to send a message to Rama. The dramatic personae in this version are:

  • Sita : kidnapped maiden who wishes to send a message
  • Rama : brave prince who is to receive the message
  • Hanuman : the honest broker who relays the message
  • Ravana : the rogue-in-the-middle who acts as the adversary. To avoid confusing first letters, let’s rename him Badmash.

There are a number of other appealing allusions in this scenario.

I think it’s a fun exercise — can one come up with other settings? Perhaps based on Gilgamesh, or Star Wars. I’m sure at least one reader of this blog could come up with a Battlestar Galactica scenario. Adama to Baltar?

Also, I couldn’t help but point to this chestnut, the real story of Alice and Bob (h/t to my father).

 

July 13, 2012

ISIT : plenaries and thoughts

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Just a few brief notes on the plenaries. Prakash Narayan gave a nice talk on his work on secrecy generation and related problems. It was nice because it tied together a number of different models in one talk so that if you were someone who had only looked at wiretap problems you could see a more unified approach to these problems. It was a little technical for my pre-breakfast brain though. Ueli Maurer gave an overview of his new approach to cryptography — I had seen a version of this before, and it was full of pictures to illustrate the reductions and interfaces he was trying to create. I think if I had more of a background in formal CS-style cryptography I might have understood it a bit better. It feels like trying to build a different style of bridge between theory (formal reasoning about security) and practice.

Abbas El Gamal gave a rather personal Shannon Lecture, taking us through a number of stages in his research life, together with some perspectives on his new book with Young-Han Kim on network information theory. He ended by calling for the IT community to really go and tackle new problems and develop new tools and models to do that. One of the things that came across more sharply for me in this ISIT, partly due to the Cover memorial, is that information theory really is a research community. Of course, there are groups and cliques and politics and problems, but each ISIT is a real coming together that reinforces that sense of community. That’s valuable.

 

April 9, 2012

ICITS Workshop Deadline Extension

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(Via Adam Smith) The deadline for submitting workshop papers to the 6th International Conference on Information Theoretic Security (ICITS) has been extended from today to Monday, April 23 (at 3pm Eastern) due to holidays. It’s in Montreal in August, so if you have some recent results that you would like to present in a workshop setting, please send them in. “Papers which broaden the applicability of information-theoretic techniques (say, to areas such as data privacy or anonymity) would also be very welcome.”

ICITS will have two tracks this year : a more CS-style conference with published proceedings, and a workshop (think ITA) track without proceedings where you can present older stuff.

 

March 16, 2012

ICITS Deadline Extension

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Due to conflicts with other deadlines and conferences, the submission
deadline for the “conference” track of ICITS 2012 — the International
Conference on Information-Theoretic Security — has been moved back
ten days to Thursday, March 22, 2012.

The “conference” deadline is now Thursday, March 22 (3pm EDT /  19:00 GMT).
The “workshop” deadline is  Monday, April 9.

ICITS will have two tracks this year, one which will act as a regular
computer science-style conference (published proceedings, original
work only) and the other which will behave more like a workshop,
without proceedings, where presentations on previously published work
or work in progress are welcome.

For more information, see the conference website.

 

February 15, 2012

ITA Workshop 2012 : More Talks

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There are some more talks to blog about, probably, but I am getting lazy, and one of them I wanted to mention was Max’s, but he already blogged a lot of it. I still don’t get what the “Herbst argument” is, though.

Vinod Prabhakaran gave a talk about indirect decoding in the 3-receiver broadcast channel. In indirect decoding, there is a “semi-private” message that is not explicitly decoded by the third receiver. However, Vinod argued that this receiver can decoded it anyway, so the indirectness is not needed, somehow. At least, that’s how I understood the talk.

Lalitha Sankar talked about two different privacy problems that could arise in “smart grid” or power monitoring situations. The first is a model of system operators (ISOs) and how to view the sharing of load information — there was a model of K different “sources” or states being observed through a channel which looked like a AWGN faded interference channel, where the fading represents the relative influence of the source (or load on the network) on the receiver (or ISO). She didn’t quite have time to go into the second model, which was more at the level of individual homes, where short-time-scale monitoring of loading can reveal pretty much all the details of what’s going on in a house. The talk was a summary of some recent papers available on her website.

Negar Kiyavash talked about timing side channel attacks — an adversary can ping your router and from the delays in the round trip times can learn pretty much what websites you are surfing. Depending on the queueing policy, the adversary can learn more or less about you. Negar showed that first come first serve (FCFS) is terrible in this regard, and there is a bit of a tradeoff wherein policies with higher delay offer more privacy. This seemed reminiscent of the work Parv did on Chaum mixing…

Lav Varshney talked about security in RFID — the presence of an eavesdropper actually detunes the RFID circuit, so it may be possible for the encoder and decoder to detect if there is an eavesdropper. The main challenge is that nobody knows the transfer function, so it has to be estimated (using a periodogram energy detector). Lav proposed a protocol in which the transmitter sends a key and the receiver tries to detect if there is an eavesdropper; if not, then it sends the message.

Tsachy Weissman talked about how to estimate directed mutual information from data. He proposed a number of estimators of increasing complexity and showed that they were consistent. The basic idea was to leverage all of the results on universal probability estimation for finite alphabets. It’s unclear to me how to extend some of these results to the continuous setting, but this is an active area of research. I saw a talk recently by John Lafferty on forest density estimation, and this paper on estimating mutual information also seems relevant.

 

February 10, 2012

Call for Papers : ICITS 2012

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I am on the PC for this conference, so I figured I would advertise the CFP here for those readers who would be interested.

6th International Conference on Information-Theoretic Security
Montreal, Quebec, Canada
August 15–17, 2012

This is the sixth in a series of conferences that aims to bring together the leading researchers in the areas of information theory, quantum information theory, and cryptography. ICITS covers all aspects of information-theoretic security, from relevant mathematical tools to theoretical modeling to implementation. Papers on all technical aspects of these topics are solicited for submission.

Note that this year there will be two distinct tracks for submission.

Important Dates:

  • Conference Track Submission: Monday, March 12, 2012
  • Conference Track Notification: Friday, May 4, 2012
  • Proceedings version: Tuesday, May 29, 2012
  • Workshop Track Submissions: Monday, April 9, 2012
  • Workshop Track Notification: Monday, May 28, 2012

Note: ICITS (Aug. 15-17, Montreal) is the week before CRYPTO 2012 (Aug. 20–23, Santa Barbara).

Two Tracks: Conference and Workshop

The goal of ICITS is to bring together researchers on all aspects of information-theoretic security. To this end, ICITS 2012 will consist of two types of contributed presentations. The conference track will act as a traditional conference (original papers with published proceedings). The workshop track will operate more like an informal workshop, with papers that have appeared elsewhere or that consist of work in progress.

  1. Conference Track (with proceedings): Submissions to this track must be original papers that have not previously appeared in published form. Accepted papers will be presented at the conference and will also be published in the conference proceedings (which will appear in Springer’s Lecture Notes in Computer Science series). We note that simultaneous submission to journals is acceptable, but simultaneous submission to other conferences with published proceedings is not.
  2. Workshop Track (no proceedings): To encourage presentation of work from a variety of fields (especially those where conference publication is unusual or makes journal publication difficult), the committee also solicits “workshop track” papers. Accepted papers will be presented orally at the conference but will not appear in
    the proceedings. Submissions to this track that have previously appeared (or are currently submitted elsewhere) are acceptable, as long as they first appeared after January 1, 2011. Papers that describe work in progress are also welcome. We note that the same standards of quality will apply to conference and workshop papers.

Conference Organization:

Program Chair: Adam Smith (Pennsylvania State University)
Program Committee:

  • Anne Broadbent (University of Waterloo)
  • Thomas Holenstein (ETH Zurich)
  • Yuval Ishai (Technion)
  • Sidharth Jaggi (CU Hong Kong)
  • Bhavana Kanukurthi (UCLA)
  • Ashish Khisti (University of Toronto)
  • Yingbin Liang (Syracuse University)
  • Prakash Narayan (University of Maryland)
  • Louis Salvail (Universite de Montreal)
  • Anand Sarwate (TTI Chicago)
  • Christian Schaffner (University of Amsterdam)
  • Adam Smith (Pennsylvania State University)
  • Stephanie Wehner (National University of Singapore)
  • Daniel Wichs (IBM Research)
  • Juerg Wullschleger (Universite de Montreal)
  • Aylin Yener (Pennsylvania State University)

General Chair: Juerg Wullschleger (Universite de Montreal)
Local Co-Chairs: Claude Crepeau (McGill University) and Alain Tapp
(Universite de Montreal)

Detailed instructions for authors can be found in the full CFP, available on the website.

 

August 12, 2011

HealthSec 2011

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I also attended HealthSec ’11 this week, and the program was a little different than what I had expected. There was a mix of technical talks and policy/framework proposals around a couple of themes:

  • security in medical devices
  • auditing in electronic medical records
  • medical record dissemination and privacy

In particular, a key challenge in healthcare coming up is how patient information is going to be handled in heath insurance exchanges (HIE’s) that will be created as part of the Affordable Care Act. The real question is what is the threat model for health information : hackers who want to wholesale health records, or the selling of data by third parties (e.g. insurance companies). Matthew Green from Dartmouth discussed implications of the PCAST report on Health Information Technology, which I will have to read.

The most interesting part of the workshop was the panel on de-identification and whether it was a relevant or useful framework moving forward. The panelists were Sean Nolan from Microsoft, Kelly Edwards from University of Washington, Arvind Narayanan from Stanford, and Lee Tien from the EFF. Sean Nolan talked a bit about how HIPAA acts as an impediment to exploratory research, which I have worked on a little, but also raised the thorny ethical issue of public good versus privacy, which is key to understanding the debate over health records in clinical research. Edwards is a bioethicist and had some very important points to raise about how informed consent is an opportunity to educate patients about their (potential) role in medical research, but also to make them feel like informed participants in the process. The way in which we phrase the tradeoff Nolan mentioned really relates to ethics in how we communicate the tradeoff to patients. Narayanan (famous for his Netflix deanonymization) talked about the relationship between technology and policy has to be rethought or turned more into a dialogue rather than a blame-shifting or challenge-posing framework. Lee Tien made a crucial point that if we do not understand how patient data moves about in our existing system, then we have no hope of reform or regulation, and no stakeholder in the system how has that “bird’s eye view” of these data flows.

I hope that in the future I can contribute to this in some way, but in the meantime I’ve been left with a fair bit to chew on. Although the conference was perhaps a bit less technical than I would have liked, I think it was quite valuable as a starting point for future work.

 

July 29, 2011

Linkage

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Via Jay P., a pretty amazing dance video.

Via 530nm330Hz, a very interesting tidbit on the history of the one-time pad. A free tech report version is available too. The one-time pad XOR’s the bits of a message with a i.i.d. random bitstring of the same length, and is credited to Gilbert Vernam and Joseph Mauborgne. However, as Steven Bellovin‘s paper shows,

In 1882, a California banker named Frank Miller published Telegraphic Code to Insure Privacy and Secrecy in the Transmission of Telegrams. In it, he describes the first one-time pad system, as a superencipherment mechanism for his telegraph code. If used properly, it would have had the same property of absolute security.

Although in theory Miller can claim priority, reality is more complex. As will be explained below, it is quite unlikely that either he or anyone else ever used his system for real messages; in fact, it is unclear if anyone other than he and his friends and family ever knew of its existence. That said, there are some possible links to Mauborgne. It thus remains unclear who should be credited with effectively inventing the one-time pad.

Another fun tidbit : apparently mother’s maiden name was used for security purposes way back in 1882!

I really like shiso leaves and their cousins. I had a shiso plant but it did not survive the California sun / I have a black thumb. One of my favorite meals at ISIT 2009 was with Bobak Nazer, where we found an out-of-the way BBQ joint where they brought us a long box filled with 7 varieties of leaves, including perilla leaves. It makes me hungry just writing about it.

Kudos to Adrienne for the amazing photo.

There’s Only One Sun, a short sci-fi film by Wong Kar-Wai.

 

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