Category Archives: Academic papers

Securing and Trusting Internet Names (SATIN 2011)

Academic papers, Call for papers, Security engineering

The inaugural SATIN workshop was held at the National Physical Laboratory (NPL) on Monday/Tuesday this week. The workshop format was presentations of 15 minutes followed by 15 minutes of discussions — so all the 49 registered attendees were able to contribute to success of the event.

Many of the papers were about DNSSEC, but there were also papers on machine learning, traffic classification, use of names by malware and ideas for new types of naming system. There were also two invited talks: Roy Arends from Nominet (who kindly sponsored the event) gave an update on how the co.uk zone will be signed, and Rod Rasmussen from Internet Identity showed how passive DNS is helping in the fight against eCrime. All the papers, and the presenters slides can be found on the workshop website.

The workshop will be run again (as SATIN 2012), probably on March 22/23 (the week before IETF goes to Paris). The CFP, giving the exact submission schedule, will appear in late August.

The PET Award: Nominations wanted for prestigious privacy award

Academic papers, Awards, Call for papers, Internet censorship, Privacy technology

The PET Award is presented annually to researchers who have made an outstanding contribution to the theory, design, implementation, or deployment of privacy enhancing technology. It is awarded at the annual Privacy Enhancing Technologies Symposium (PETS).

The PET Award carries a prize of 3000 USD thanks to the generous support of Microsoft. The crystal prize itself is offered by the Office of the Information and Privacy Commissioner of Ontario, Canada.

Any paper by any author written in the area of privacy enhancing technologies is eligible for nomination. However, the paper must have appeared in a refereed journal, conference, or workshop with proceedings published in the period from August 8, 2009 until April 15, 2011.

The complete award rules including eligibility requirements can be found under the award rules section of the PET Symposium website.

Anyone can nominate a paper by sending an email message containing the following to award-chair11@petsymposium.org.

  • Paper title
  • Author(s)
  • Author(s) contact information
  • Publication venue and full reference
  • Link to an available online version of the paper
  • A nomination statement of no more than 500 words.

All nominations must be submitted by April 15th, 2011. The Award Committee will select one or two winners among the nominations received. Winners must be present at the PET Symposium in order to receive the Award. This requirement can be waived only at the discretion of the PET Advisory board.

More information about the PET award (including past winners) is available at http://petsymposium.org/award/

More information about the 2011 PET Symposium is available at http://petsymposium.org/2011.

Pico: no more passwords!

Academic papers, Authentication, Protocols, Security engineering, Usability

Passwords are no longer acceptable as a security mechanism. The arrogant security people ask users that passwords be memorable, unguessable, high entropy, all different and never written down. With the proliferation of the number of passwords and the ever-increasing brute-force capabilities of modern computers, passwords of adequate strength are too complicated for human memory, especially when one must remember dozens of them. The above demands cannot all be satisfied simultaneously. Users are right to be pissed off.

A number of proposals have attempted to find better alternatives for the case of web authentication, partly because the web is the foremost culprit in the proliferation of passwords and partly because its clean interfaces make technical solutions tractable.

For the poor user, however, a password is a password, and it’s still a pain in the neck regardless of where it comes from. Users aren’t fed up with web passwords but with passwords altogether. In “Pico: no more passwords, the position paper I’ll be presenting tomorrow morning at the Security Protocols Workshop, I propose a clean-slate design to get rid of passwords everywhere, not just online. A portable gadget called Pico transforms your credentials from “what you know” into “what you have”.

A few people have already provided interesting feedback on the pre-proceedings draft version of the paper. I look forward to an animated discussion of this controversial proposal tomorrow. Whenever I serve as help desk for my non-geek acquaintances and listen to what drives them crazy about computers I feel ashamed that, with passwords, we (the security people) impose on them such a contradictory and unsatisfiable set of requests. Maybe your gut reaction to Pico will be “it’ll never work”, but I believe we have a duty to come up with something more usable than passwords.

[UPDATE: the paper can also be downloaded from my own Cambridge web site, where the final version will appear in due course.]

Can we Fix Federated Authentication?

Academic papers, Authentication, Banking security, Legal issues, Protocols, Security economics, Security engineering, Social networks, Web security

My paper Can We Fix the Security Economics of Federated Authentication? asks how we can deal with a world in which your mobile phone contains your credit cards, your driving license and even your car key. What happens when it gets stolen or infected?

Using one service to authenticate the users of another is an old dream but a terrible tar-pit. Recently it has become a game of pass-the-parcel: your newspaper authenticates you via your social networking site, which wants you to recover lost passwords by email, while your email provider wants to use your mobile phone and your phone company depends on your email account. The certification authorities on which online trust relies are open to coercion by governments – which would like us to use ID cards but are hopeless at making systems work. No-one even wants to answer the phone to help out a customer in distress. But as we move to a world of mobile wallets, in which your phone contains your credit cards and even your driving license, we’ll need a sound foundation that’s resilient to fraud and error, and usable by everyone. Where might this foundation be? I argue that there could be a quite surprising answer.

The paper describes some work I did on sabbatical at Google and will appear next week at the Security Protocols Workshop.

JPEG canaries: exposing on-the-fly recompression

Academic papers

Many photo-sharing websites decompress and compress uploaded images, to enforce particular compression parameters. This recompression degrades quality. Some web proxies can also recompress images/videos, to give the impression of a faster connection.

In Towards copy-evident JPEG images (with Markus Kuhn, in Lecture Notes in Informatics), we present an algorithm for imperceptibly marking JPEG images so that the recompressed copies show a clearly-visible warning message. (Full page demonstration.)

Original image:

Original image

After recompression:

The image after recompression, with a visible warning message

(If you can’t see the message in the recompressed image, make sure your browser is rendering the images without scaling or filtering.)

Richard Clayton originally suggested the idea of trying to create an image which would show a warning when viewed via a recompressing proxy server. Here is a real-world demonstration using the Google WAP proxy.

Our marking technique is inspired by physical security printing, used to produce documents such as banknotes, tickets, academic transcripts and cheques. Photocopied versions will display a warning (e.g. ‘VOID’) or contain obvious distortions, as duplication turns imperceptible high-frequency patterns into more noticeable low-frequency signals.

Our algorithm works by adding a high-frequency pattern to the image with an amplitude carefully selected to cause maximum quantization error on recompression at a chosen target JPEG quality factor. The amplitude is modulated with a covert warning message, so that foreground message blocks experience maximum quantization error in the opposite direction to background message blocks. While the message is invisible in the marked original image, it becomes visible due to clipping in a recompressed copy.

The challenge remains to extend our approach to mark video data, where rate control and adaptive quantization make the copied document’s properties less predictable. The result would be a digital video that would be severely degraded by recompression to a lower quality, making the algorithm useful for digital content protection.

A Merry Christmas to all Bankers

Academic papers, Banking security, Internet censorship, Legal issues, News coverage, Politics, Security engineering

The bankers’ trade association has written to Cambridge University asking for the MPhil thesis of one of our research students, Omar Choudary, to be taken offline. They complain it contains too much detail of our No-PIN attack on Chip-and-PIN and thus “breaches the boundary of responsible disclosure”; they also complain about Omar’s post on the subject to this blog.

Needless to say, we’re not very impressed by this, and I made this clear in my response to the bankers. (I am embarrassed to see I accidentally left Mike Bond off the list of authors of the No-PIN vulnerability. Sorry, Mike!) There is one piece of Christmas cheer, though: the No-PIN attack no longer works against Barclays’ cards at a Barclays merchant. So at least they’ve started to fix the bug – even if it’s taken them a year. We’ll check and report on other banks later.

The bankers also fret that “future research, which may potentially be more damaging, may also be published in this level of detail”. Indeed. Omar is one of my coauthors on a new Chip-and-PIN paper that’s been accepted for Financial Cryptography 2011. So here is our Christmas present to the bankers: it means you all have to come to this conference to hear what we have to say!

Financial Cryptography and Data Security 2011 — Call for Participation

Academic papers, Banking security, Call for papers, Security engineering

Financial Cryptography and Data Security (FC 2011)
Bay Gardens Beach Resort, St. Lucia
February 28 — March 4, 2011

Financial Cryptography and Data Security is a major international forum for research, advanced development, education, exploration, and debate regarding information assurance, with a specific focus on commercial contexts. The conference covers all aspects of securing transactions and systems.

NB: Discounted hotel rate is available only until December 30, 2010

Topics include:

Anonymity and Privacy, Auctions and Audits, Authentication and Identification, Backup Authentication, Biometrics, Certification and Authorization, Cloud Computing Security, Commercial Cryptographic Applications, Transactions and Contracts, Data Outsourcing Security, Digital Cash and Payment Systems, Digital Incentive and Loyalty Systems, Digital Rights Management, Fraud Detection, Game Theoretic Approaches to Security, Identity Theft, Spam, Phishing and Social Engineering, Infrastructure Design, Legal and Regulatory Issues, Management and Operations, Microfinance and Micropayments, Mobile Internet Device Security, Monitoring, Reputation Systems, RFID-Based and Contactless Payment Systems, Risk Assessment and Management, Secure Banking and Financial Web Services, Securing Emerging Computational Paradigms, Security and Risk Perceptions and Judgments, Security Economics, Smartcards, Secure Tokens and Hardware, Trust Management, Underground-Market Economics, Usability, Virtual Economies, Voting Systems

Important Dates

Hotel room reduced rate cut-off: December 30, 2010
Reduced registration rate cut-off: January 21, 2011

Please send any questions to fc11general@ifca.ai

Continue reading Financial Cryptography and Data Security 2011 — Call for Participation →

Research, public opinion and patient consent

Academic papers, Legal issues, Politics, Privacy technology

Paul Thornton has brought to my attention some research that the Department of Health published quietly at the end of 2009 (and which undermines Departmental policy).

It is the Summary of Responses to the Consultation on the Additional Uses of Patient Data undertaken following campaigning by doctors, NGOs and others about the Secondary Uses Service (SUS). SUS keeps summaries of patient care episodes, some of them anonymised, and makes them available for secondary uses; the system’s advocates talk about research, although it is heavily used for health service management, clinical audit, answering parliamentary questions and so on. Most patients are quite unaware that tens of thousands of officials have access to their records, and the Database State report we wrote last year concluded that SUS is almost certainly illegal. (Human-rights and data-protection law require that sensitive data, including health data, be shared only with the consent of the data subject or using tightly restricted statutory powers whose effects are predictable to data subjects.)

The Department of Health’s consultation shows that most people oppose the secondary use of their health records without consent. The executive summary tries to spin this a bit, but the data from the report’s body show that public opinion remains settled on the issue, as it has been since the first opinion survey in 1997. We do see some signs of increasing sophistication: now a quarter of patients don’t believe that data can be anonymised completely, versus 15% who say that sharing is “OK if anonymised” (p 23). And the views of medical researchers and NHS administrators are completely different; see for example p 41. The size of this gap suggests the issue won’t get resolved any time soon – perhaps until there’s an Alder-Hey-type incident that causes a public outcry and forces a reform of SUS.

Capsicum: practical capabilities for UNIX

Academic papers, Awards, Operating systems

Today, Jonathan Anderson, Ben Laurie, Kris Kennaway, and I presented Capsicum: practical capabilities for UNIX at the 19th USENIX Security Symposium in Washington, DC; the slides can be found on the Capsicum web site. We argue that capability design principles fill a gap left by discretionary access control (DAC) and mandatory access control (MAC) in operating systems when supporting security-critical and security-aware applications.

Capsicum responds to the trend of application compartmentalisation (sometimes called privilege separation) by providing strong and well-defined isolation primitives, and by facilitating rights delegation driven by the application (and eventually, user). These facilities prove invaluable, not just for traditional security-critical programs such as tcpdump and OpenSSH, but also complex security-aware applications that map distributed security policies into local primitives, such as Google’s Chromium web browser, which implement the same-origin policy when sandboxing JavaScript execution.

Capsicum extends POSIX with a new capability mode for processes, and capability file descriptor type, as well as supporting primitives such as process descriptors. Capability mode denies access to global operating system namespaces, such as the file system and IPC namespaces: only delegated rights (typically via file descriptors or more refined capabilities) are available to sandboxes. We prototyped Capsicum on FreeBSD 9.x, and have extended a variety of applications, including Google’s Chromium web browser, to use Capsicum for sandboxing. Our paper discusses design trade-offs, both in Capsicum and in applications, as well as a performance analysis. Capsicum is available under a BSD license.

Capsicum is collaborative research between the University of Cambridge and Google, and has been sponsored by Google, and will be a foundation for future work on application security, sandboxing, and security usability at Cambridge and Google. Capsicum has also been backported to FreeBSD 8.x, and Heradon Douglas at Google has an in-progress port to Linux.

We’re also pleased to report the Capsicum paper won Best Student Paper award at the conference!

Passwords in the wild, part IV: the future

Academic papers, Authentication, Protocols, Security economics, Security engineering

This is the fourth and final part in a series on password implementations at real websites, based on my paper at WEIS 2010 with Sören Preibusch.

Given the problems associated with passwords on the web outlined in the past few days, for years academics have searched for new technology to replace passwords. This thinking can at times be counter-productive, as no silver bullets have yet materialised and this has distracted attention away from fixing the most pressing problems associated with passwords. Currently, the trendiest proposed solution is to use federated identity protocols to greatly reduce the number of websites which must collect passwords (as we’ve argued would be a very positive step). Much focus has been given to OpenID, yet it is still struggling to gain widespread adoption. OpenID was deployed at less than 3% of websites we observed, with only Mixx and LiveJournal giving it much prominence.

Nevertheless, we optimistically feel that real changes will happen in the next few years, as password authentication on the web seems to be becoming increasingly unsustainable due to the increasing scale and interconnectivity of websites collecting passwords. We actually think we are already in the early stages of a password revolution, just not of the type predicted by academia.

Continue reading Passwords in the wild, part IV: the future →