Cracks Are Found In Smartcard Security (fwd)

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[This was on the Defcon list...apologies if it's already been posted today.]


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---------- Forwarded message ----------
Date: Tue, 19 Nov 1996 21:17:49 +0000
From: Simon Gardner <simon at access.org.uk>
To: aaa-list at access.org.uk
Cc: dc-stuff at dis.org
Subject: Cracks Are Found In Smartcard Security

Cracks Are Found In Smartcard Security


Researchers have found a way to attack tough codes, says Michael
McCormack.

A team of Cambridge and German researchers have used ordinary hacking
methods and £150 worth of electronics equipment to crack the "world's
most secure computer chip", used in automated teller machines worldwide.

They say their technique could be used to reprogram a wide variety of
supposedly secure smartcard applications, including the Mondex "money on
a card" bankcard, GSM phones, and satellite TV descramblers.

Dr Ross Anderson, of Cambridge University Computer Laboratory, working
with German researcher Markus Kuhn, used methods pioneered by Sky-TV
hackers to crack the Dallas chip, described by the manufacturer as
having "the most sophisticated security features available in any
microcontroller" and used in most of Britain's cash machines.

The chip decodes the information read from bankcards and authorises the
bank machine to process transactions ordered by the owner. It is also
used by the Mondex system to verify the amount of electronic money
available to the cardholder.

Anderson and Kuhn used cheap and easily built electronic equipment to
send wrong instructions to the chip, observing how it encrypted bad
data. By sending such errors through all parts of the encryption system,
they could work out its key.

"You will have to have backup security"

"Once you know that, you can instruct it to put some zeros on the end of
your Mondex balance, start unscrambling your satellite feed, anything
you like," Anderson said. "Breaking the average smartcard can be done by
anyone with a modicum of technical knowledge by the methods we have
described. The expense is negligible but it is time-consuming."

Their discovery could spell the end of the Mondex system, which relies
entirely on the security of the smartcards for its integrity. "I don't
think you will be able to have floating systems like Mondex any more,
where all the information is held on the smartcards," said Anderson.

"You will have to have backup security with authorisation calls and
auditing, just like ordinary credit cards. The smartcards are no longer
reliable on their own."

John Beric, head of security at Mondex, said security was a moving
target, and he was unconcerned by the findings. "I welcome Dr Anderson's
work, because it's a benchmark that establishes the difficulty of
breaking the system," he said. "I take some comfort that it's taken a
Cambridge academic and a very bright student to do this."

Beric said Mondex had a scheme for continually improving its security by
transparently introducing new smartcard chips every two years. "It's not
static, we're ahead of the criminal now, and we believe the technology
is there to ensure that we stay ahead."

Anderson said his latest research indicated that two of the world's most
widely used systems for encoding sensitive financial information - the
RSA and DES encryption standards used by most banks - could also be
cracked easily."

[The London Telegraph, 19th November 1996]