RF Protection For Credit Cards?

M

maury

Joined
Sep 24, 2000
Messages
606
I have seen ads for wallets that purport to shield credit cards and passports from RF waves. Sellers claim it is possible for bad guys to actually copy personal data off them while they are in your pocket.

So, first off, is there any real evidence that this is actually happening? Or is this just another hype (remember those sticky plastic sheets you were supposed to stick on your cell phone to protect your brain?)?

Now, if this really is a potential threat, is it possible and/or practical to line my wallet or passport case with something to protect stuff? Lead? Aluminium foil? Mylar? Peanut Butter?
 
only way for them to scan your card is if they have an RFID chip in them.

I carry a flipside wallet and i know for a fact it blocks the RFID signal, our badges at work use RFID to scan in and out of the building. I was curious, so i closed my badge in the wallet and was unable to scan in.
 
We've discussed this in the past. The word "Faraday Shield" is often used. Rest assured that none of these wallets forms a Faraday shield. What they can do is capacitively short out the RF circuitry in the card. This is harmless to the card. When removed from the wallet, the card will return to functioning normally. The exact same thing can be accomplished with a piece of common kitchen foil. There is no need to wrap the card. Just one piece long one side of the card is all the is required.
 
Can you post a picture Gollnick? Maybe Ixer could test this. It sounds interesting. But I'd hate to have a piece of foil lining an inside pocket with the card facing the wrong side giving me a false sense of security.
 
The cards that do have RFID in them are called "passive" RFID meaning they use the energy that is being transmitted to them to provide a "response". As far as my understanding of physics goes, RF waves tend to be absorbed particularly well by flat metal surfaces, where they spread out and dissipate the energy as very small eddy currents (which is then put out as very small amounts of heat). Even the parts of the signal that "pass" through are generally too distorted to be recognized by the card let alone have enough power to retransmit BACK through that metal. It doesn't take much, if you're worried about it you could throw a piece of foil behind your dollar bills so that it shields everything inside when it's folded up and doesn't get in your way when trying to use your card
 
And yeah...it is definitely possible for someone to do this. It takes a fairly large RFID reader to read from more than a foot or two away though.
 
It's very possible, and happening. A cheap way to shield is wrapping duct tape around your cards, then tinfoil, then more tape.
 
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