[LINK] RFI: Disabling an NFC Coil on PayPass/Wave

[Tom Worthington]

On 17/08/14 08:20, Roger Clarke wrote:
> ... break the coil and prevent the undesired wireless mechanism
> working ...

Linuxcentre suggests a 7mm cut down from the top edge of the card: 
http://linuxcentre.net/disabling-contactless-cards

An alternative might be to stick conductive window film to the back of 
the card. This plastic film has a thin layer of aluminium to block radio 
signals (similar to the silvery plastic which electronic components are 
shipped in). The plastic would cost about 30 cents per card: 
http://www.lessemf.com/plastic.html

> The location can be found using an x-ray machine, or perhaps with
> very strong light. ...

With a 3 Watt LED I was able to see the conductive paths along the 
bottom of a card, 5mm from the edge. I couldn't see it at the top as 
this was obscured by the magnetic stripe.

I don't have an x-ray machine readily to hand. But someone in the ANU 
Fellows Bar Friday night said they had spent the day lining a room with 
lead for a new machine. So perhaps ... ;-)

ps: Would it be simpler to ask around, to see if there is a financial 
institution which will issue contact-only cards.


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