Posts filed under 'Academic papers

Mar 5, '14

Bank names are so tricksy — they all have similar words in them… and so it’s common to see phishing feeds with slightly the wrong brand identified as being impersonated.

However, this story is about how something the way around has happened, in that AnonGhost, a hacker group, believe that they’ve defaced “Yorkshire Bank, one of the largest United Kingdom bank” and there’s some boasting about this to be found at

However, it rather looks to me as if they’ve hacked an imitation bank instead! A rather less glorious exploit from the point of view of potential admirers.

Mar 3, '14

I will be trying to liveblog Financial Cryptography 2014. I just gave a keynote talk entitled “EMV – Why Payment Systems Fail” summarising our last decade’s research on what goes wrong with Chip and PIN. There will be a paper on this out in a few months; meanwhile here’s the slides and here’s our page of papers on bank security.

The sessions of refereed papers will be blogged in comments to this post.

Feb 21, '14

Next year’s Workshop on the Economics of Information Security (WEIS 2014) will be at Penn State on June 23–24. Submissions are due a week from today, at the end of February. It will be fascinating to see what effects the Snowden revelations will have on the community’s thinking. Get writing!

Feb 5, '14

Today we release a paper on security protocols and evidence which analyses why dispute resolution mechanisms in electronic systems often don’t work very well. On this blog we’ve noted many many problems with EMV (Chip and PIN), as well as other systems from curfew tags to digital tachographs. Time and again we find that electronic systems are truly awful for courts to deal with. Why?

The main reason, we observed, is that their dispute resolution aspects were never properly designed, built and tested. The firms that delivered the main production systems assumed, or hoped, that because some audit data were available, lawyers would be able to use them somehow.

As you’d expect, all sorts of things go wrong. We derive some principles, and show how these are also violated by new systems ranging from phone banking through overlay payments to Bitcoin. We also propose some enhancements to the EMV protocol which would make it easier to resolve disputes over Chip and PIN transactions.

Update (2013-03-07): This post was mentioned on Bruce Schneier’s blog, and this is some good discussion there.

Update (2014-03-03): The slides for the presentation at Financial Cryptography are now online.

Jan 20, '14

Today Robert Brady and I publish a paper that solves an outstanding problem in physics. We explain the beautiful bouncing droplet experiments of Yves Couder, Emmanuel Fort and their colleagues.

For years now, people interested in the foundations of physics have been intrigued by the fact that droplets bouncing on a vibrating tray of fluid can behave in many ways like quantum mechanical particles, with single-slit and double-slit diffraction, tunneling, Anderson localisation and quantised orbits.

In our new paper, Robert Brady and I explain why. The wave field surrounding the droplet is, to a good approximation, Lorentz covariant with the constant c being the speed of surface waves. This plus the inverse square force between bouncing droplets (which acts like the Coulomb force) gives rise to an analogue of the magnetic force, which can be observed clearly in the droplet data. There is also an analogue of the Schrödinger equation, and even of the Pauli exclusion principle.

These results not only solve a fascinating puzzle, but might perhaps nudge more people to think about novel models of quantum foundations, about which we’ve written three previous papers.

Jan 3, '14

David Modic and I have just published a paper on The psychology of malware warnings. We’re constantly bombarded with warnings designed to cover someone else’s back, but what sort of text should we put in a warning if we actually want the user to pay attention to it?

To our surprise, social cues didn’t seem to work. What works best is to make the warning concrete; people ignore general warnings such as that a web page “might harm your computer” but do pay attention to a specific one such as that the page would “try to infect your computer with malware designed to steal your bank account and credit card details in order to defraud you”. There is also some effect from appeals to authority: people who trust their browser vendor will avoid a page “reported and confirmed by our security team to contain malware”.

We also analysed who turned off browser warnings, or would have if they’d known how: they were people who ignored warnings anyway, typically men who distrusted authority and either couldn’t understand the warnings or were IT experts.

Dec 20, '13

It’s been a busy year for Capsicum, practical capabilities for UNIX, so a year-end update seemed in order:

The FreeBSD Foundation and Google jointly funded a Capsicum Integration Project that took place throughout 2013 — described by Foundation project technical director Ed Maste in a recent blog article. Pawel Jakub Dawidek refined several Capsicum APIs, improving support for ioctls and increasing the number of supported capability rights for FreeBSD 10. He also developed Casper, a helper daemon that provides services (such as DNS, access to random numbers) to sandboxes — and can, itself, sandbox services. Casper is now in the FreeBSD 11.x development branch, enabled by default, and should appear in FreeBSD 10.1. The Google Open Source Program Office (OSPO) blog also carried a September 2013 article on their support for open-source security, featuring Capsicum.

Capsicum is enabled by default in the forthcoming FreeBSD 10.0 release — capability mode, capabilities, and process descriptors are available in the out-of-the-box GENERIC kernel. A number of system services use Capsicum to sandbox themselves — such as the DHCP client, high-availability storage daemon, audit log distribution daemon, but also command-line tools like kdump and tcpdump that handle risky data. Even more will appear in FreeBSD 10.1 next year, now that Casper is available.

David Drysdale at Google announced Capsicum for Linux, an adaptation of Linux to provide Capsicum’s capability mode and capabilities, in November 2013. David and Ben Laurie visited us in Cambridge multiple times this year to discuss the design and implementation, review newer Capsicum APIs, and talk about future directions. They hope to upstream this work to the Linux community. Joris Giovannangeli also announced an adaptation of Capsicum to DragonFlyBSD in October 2013.

Over the summer, Mariusz Zaborski and Daniel Peryolon were funded by Google Summer of Code to work on a variety of new Capsicum features and services, adapting core UNIX components and third-party applications to support sandboxing. For example, Mariusz looked at sandboxing BSD grep: if a vulnerability arises in grep’s regular-expression matching, why should processing a file of malicious origin yield full rights to your UNIX account?

In May 2013, our colleagues at the University of Wisconsin, Madison, led by Bill Harris, published a paper at the IEEE Symposium on Security and Privacy (“Oakland”) on “Declarative, Temporal, and Practical Programming with Capabilities” — how to model program behaviour, and automatically transform some classes of applications to use Capsicum sandboxing. We were very pleased to lend a hand with this work, and feel the art of programming for compartmentalisation is a key research challenge. We also collaborated with folk at SRI and Google on a a workshop paper developing our ideas about application compartmentalisation, which appeared at the Security Protocols Workshop here in Cambridge in March 2013.

Google and the FreeBSD Foundation are committed to further work on Capsicum and its integration with applications, and research continues on how to apply Capsicum at several institutions including here at Cambridge. We hope to kick off a new batch of application adaptation in coming months — as well as integration with features such as DNSSEC. However, we also need your help in adapting applications to use Capsicum on systems that support it!

Dec 15, '13

Next year’s Workshop on the Economics of Information Security (WEIS 2014) will be at Penn State on June 23–24. The call for papers is now out; papers are due by the end of February.

It will be fascinating to see what effects the Snowden revelations will have on the community’s thinking about security standards and regulation, the incentives for information sharing and cooperation, and the economics of privacy, to mention only three of the workshop’s usual topics. Now that we’ve had six months to think things through, how do you think the security game has changed, and why? Do we need minor changes to our models, or major ones? Are we in the same policy world, or a quite different one? WEIS could be particularly interesting next year. Get writing!

Nov 8, '13

Today we’re presenting a new side-channel attack in PIN Skimmer: Inferring PINs Through The Camera and Microphone at SPSM 2013. We found that software on your smartphone can work out what PIN you’re entering by watching your face through the camera and listening for the clicks as you type. Previous researchers had shown how to work out PINs using the gyro and accelerometer; we found that the camera works about as well. We watch how your face appears to move as you jiggle your phone by typing.

There are implications for the design of electronic wallets using mechanisms such as Trustzone which enable some apps to run in a more secure sandbox. Such systems try to prevent sensitive data such as bank credentials being stolen by malware. Our work shows it’s not enough for your electronic wallet software to grab hold of the screen, the accelerometers and the gyro; you’d better lock down the video camera, and the still camera too while you’re at it. (Our attack can use the still camera in burst mode.)

We suggest ways in which mobile phone operating systems might mitigate the risks. Meanwhile, if you’re developing payment apps, you’d better be aware that these risks exist.

Nov 3, '13

Three of our clients have been acquitted of tampering with curfew tags after the Ministry of Justice and G4S were unwilling to have an independent forensic team examine their evidence. This brings to five the number of tag-tampering prosecutions that have been withdrawn or collapsed when the defence says “Right, prove it then.” I reported the first case here.

The three latest matters were high-profile terrorism cases, involving three of the nine men tagged under the new Terrorism Prevention and Investigation Measure (TPIM) – a kind of national-security ASBO handed out by MI5, and which had already been criticised by David Anderson QC, the government’s independent reviewer of terrorism legislation, for low standards of proof. Unlike a normal ASBO which a court gives “on the balance of probabilities”, you can get a TPIM if the Home Secretary declares she has a “reasonable suspicion”.

The Ministry of Justice should perhaps, when they let the tagging contracts, have read our 1994 paper on the John Munden case, or the post here about the similar case of Jane Badger. If you’re designing a system one of whose functions is to provide evidence, you’d better design it to withstand hostile review. “Trust us” doesn’t cut it in criminal trials, and neither does “I’m afraid that’s commercially confidential.”


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