Contactless bank cards

Peter Tomlinson pwt at
Wed Nov 17 07:22:37 GMT 2010

Mary, are you sure that you are not thinking about mag stripe hotel 
cards? Like mag stripe transport tickets, electromagnets can corrupt 
those. However, very simple chip memory cards (not capable of having any 
authentication handshake) might be corrupted by interference effects 
from electronic equipment or even from the RF field generated by a spark.


Mary Hawking wrote:
> How robust is the RFID chip?
> At NEC, there are, apparently, electromagnets somewhere - and if you have
> one of those individually programmed hotel door cards, they get wiped - and
> have to be re-programmed before you can get into your room again.
> What would wipe an Oyster card?
> Mary Hawking
> -----Original Message-----
> From: Roland Perry [mailto:lists at] 
> Sent: 16 November 2010 15:11
> To: ukcrypto at
> Subject: Re: Contactless bank cards
> In article 
> <AANLkTinR+ppkizFHcY3a2Uxcbuh0-1OTg10=eq5HuUdK at>, Francis 
> Davey <fjmd1a at> writes
>> Actually my first worry on seeing these things advertised was
>> something entirely legal. Along the lines of an unobtrusive sign
>> saying "entrance fee £5" or something like that. Auto charge people as
>> they walk in (does contactless have that range? Or will it)
> I've never actually found a machine to try my card out upon. But the 
> Oyster pads in London require the card to be pretty much out of a wallet 
> and touching the surface. Similarly the RFID cards used on the buses in 
> Nottingham. The technology is dozens of order of magnitude away from 
> scanning the bus pass in the passenger's pocket as he gets on board.

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