"tim....." wrote in message
...
Nope. There is no reason why touching your card on an incompatible pad
would render the card unusable, unless the software was written to do this
(by accident or design) in the same way as say entering your bank (or
mobile phone) PIN in incorrectly.

You can mungle the data on a card though. Corrupt the cypher or something
like that. Break one of the application areas although there is no reason
you cant fix it with a programmer.

Issuing such cards with no way to reset them by software would be remiss
of the designers.

I have never disabled a *card* of this type - its normally remove the CSN
from the system and the card is then usless - you can't re-use the card for
something else unless you know the cypher to access the application areas to
re-write the data.

Some smart cards are 'fused' but I've only ever seen something like this on
active cards (Those with the battery inside them) Iclass and MIFARE cards
are fused but the fuses only relate to the changing of the cyphers not
killing the card.

My guess is that the reset requires the card to be attached to special
hardware and they decided that collecting all the cards and doing this
centrally was easer than doing it at every Underground station.

You would normally need a proper programmer (like we have for ACS) where you
can change the keys and application area content, the normal read/writers
won't fix the card you need a proper programmer terminal.

Have a look at http://www.quantasoft.com/Documents/HID/0028_an_en.pdf - This
should give you an idea. Its the memory map for the HID Iclass cards. -
There is no application note on the HIDCorp site for the MIFARE