STE WILLIAMS

Cambridge boffins rebuff banking industry take down request

Computer scientists from Cambridge University have rebuffed attempts by a banking association to persuade them to take down a thesis covering the shortcomings of Chip-and-PIN as a payment verification method.

Omar Choudary’s masters thesis contains too much information about how it might be possible to fool a retailing terminal into thinking a PIN authorising a purchase had been entered, as far as the bankers are concerned. Noted cryptographer and banking security expert Professor Ross Anderson gives short shrift to the argument that publishing the research exceeds the bounds of responsible disclosure, politely but firmly telling the UK Cards Association that the research was already in the public domain and that Choudary’s work would stay online.

Anderson is one of Choudary’s supervisors in the latter’s research.

Choudary’s research on so-called NO-PIN attacks builds on work by Steven Murdoch, Saar Drimer and Anderson that was disclosed to the banking industry last year and published back in February.

Chip-and-PIN is used throughout Europe and in Canada as a method to authorise credit and debit card payments. The attack unearthed by the Cambridge researchers creates a means to trick a card into thinking a chip-and-signature transaction is taking place while the terminal thinks it’s authorised by chip-and-PIN. The flaw creates a means to make transactions that are “Verified by PIN” using a stolen (uncancelled) card without knowing the PIN code. The ruse works by installing a wedge between the card and terminal.

The same approach cannot be applied to make ATM transactions.

In the months since the potential loophole was uncovered only Barclays Bank has responded by modifying its technology to block the potential scam, Anderson reports.

Choudary is one of the authors of an upcoming paper on Chip-and-PIN security, due to be unveiled at the Financial Cryptography 2011 conference in February