On Tue, 18 Nov 2003 07:42:09 +0000, John Hadstate wrote:
(Matthew) wrote in message . com...
I am interested in the mechanics of these cards, which are smart cards
for use on London's transport system. One would hope given the
reported £1billion+ that they are secure.
Smartcards are amongst the most secure ways to store information and
users of Oyster can be confident of the security of the data on their
card.
Says who?
Of course, this was a quote from either the transport company, who
spent a lot of money on this and is therefore convinced that it must
be secure or from the manufacurer that certainly will not make much money
by selling insecure products.
Nevertheless, I think that the statement that smart cards are one of the
most secure ways to store information is basically correct.
Access to the information is only possible using secret keys
specific to that card, known only to devices permitted to process the
cards. These cards are very difficult to break into, making the cards
very secure; in the unlikely event that a card has its key broken
then the system - and all other cards - will remain secure.
All of the above adds up to a classic case of "security by obscurity."
It might, when they have let some incompetent persons design the
system. On the other hand, virtually all companies are highly
secretive about their security measures, but this does not necessarily
imply that these measures are inadequate.
This might mean that the inventors have already identified or suspect
weaknesses in their system that they hope will remain undiscovered if
no one is permitted to analyze their system too closely.
Smartcard companies have employed some very competent people. For
example, one of the main designers of the electronic smart card purse,
that we use here, was Joan Daemen (also responsible for Rijndael).
Smartcards are basically dedicated crypto engines, and you can use
them to build very secure systems (and yes you can also use them
to build insecure systems). Just like other forms of cryptography
smartcards are generally the strongest part of the system, and
most attackers will simply try to attack the other parts.
greetings,
Ernst Lippe