Do those RFID shielded wallets and bags actually work to protect your contactless credit cards?
Systems like VISA PayWave and Mastercard PayPass.
Does aluminium foil work?
Dave does some measurements to find out using a H-Field probe
TekBox EMC probe set:
http://amzn.to/1YkCLPO
I was watching at 16:00 in 0.5 speed to see if I could figure out any of the credit card numbers since the tape got a little pushed into the card. I thought I saw the 12th really clear, but not so sure anymore. I don't think anyone would be able to get anything useful from it.
Anyway, your inflections and sentence pacing sounds hilarious like Bill Cosby at 0.5 speed
Could you use a hole punch to punch a hole through the windings (in one corner of the card) to essentially disable the contact-less payment option (forcing you to use the chip)?
(Apologies if this was answered in the video, I didn't get time to watch it the whole way through.)
Could you use a hole punch to punch a hole through the windings (in one corner of the card) to essentially disable the contact-less payment option (forcing you to use the chip)?
Possible.
A tiny drill would on the coil would do it.
I just tested the alu foil on my own bank card and found that it not only works when lying over the card, it also works lying under the card (i.e. with no foil over it). So you don't even have to wrap foil around the card, a single layer in close vicinity is enough!
Not until you lift the card up about half a cm away from the alu foil will the NFC be able to read the card.
Does the alu foil reflect and those reflections interfere enough for it to become unreadable?
I just tested the alu foil on my own bank card and found that it not only works when lying over the card, it also works lying under the card (i.e. with no foil over it). So you don't even have to wrap foil around the card, a single layer in close vicinity is enough!
Not until you lift the card up about half a cm away from the alu foil will the NFC be able to read the card.
Does the alu foil reflect and those reflection interfere enough for it to become unreadable?
My guess is it ruins the "tuned" antenna match.
/Bingo
Could you use a hole punch to punch a hole through the windings (in one corner of the card) to essentially disable the contact-less payment option (forcing you to use the chip)?
Possible.
A tiny drill would on the coil would do it.
The antenna in mine fail after a few months of flexing in my back pocket wallet. I toyed with using a small blade but a drill bit would be tidier and opening the antenna.
Please note that bank cards are not your property, but the bank's. Messing with them may cause them to be not amused.
Over here you can request a bank card without NFC capabilities, some banks also supply shielding holders, on special request.
It is not true that at the low kHz range aluminium does not affect the coupling.
I have done a lot of work in proof-of-concept for a device recently using 134 kHz animal RFID transponders. The coupling between the transponder and the reader is in fact affected by aluminium shielding at these very low frequencies. Aluminium foil has a very minimal effect, but a 20mm aluminium tube with a 2mm wall thickness seriously attenuates the coupling to the point the device cannot be read.
My shwmbo bought some of these for a recent trip through asia.
Just tested it with my phone. Works quite well can't read the credit card when its in the sleeve
It is not true that at the low kHz range aluminium does not affect the coupling.
I didn't mean to imply that. In fact the graph I showed effectively stats the opposite (i.e. it has non-zero attenuation)
This was the first video my girlfriend also wanted to watch due to the nice bag, she really liked the bag Dave, your wife has good taste
What I find remarkable is that the layout of the gold pads of the security pinchip is also modified in comparison to the card without RFID. I saw this change when my bankcards got rfid and see it also on your card, there are circular antenna like thin golden traces added around the normal 6-8 pads.
Does anyone have any idea where they are for? Perhaps protection against the rfid field or also another nfc wireless communication channel?
Could you use a hole punch to punch a hole through the windings (in one corner of the card) to essentially disable the contact-less payment option (forcing you to use the chip)?
Possible.
A tiny drill would on the coil would do it.
Tried and tested, works fine. Another option is microwaving the card but that may damage the smart card chip too.
I just tested the alu foil on my own bank card and found that it not only works when lying over the card, it also works lying under the card (i.e. with no foil over it). So you don't even have to wrap foil around the card, a single layer in close vicinity is enough!
Not until you lift the card up about half a cm away from the alu foil will the NFC be able to read the card.
Does the alu foil reflect and those reflection interfere enough for it to become unreadable?
The effect of alu foil is NOT shielding. RFID works by magnetic coupling, and alu is not magnetic. What the alu does is absorb energy due to eddy-current losses, severely damping the signal so not enough energy reaches the card to power it, so it doesn't matter where it is as long as it can absorb enough of the field energy. Copper would be even better.
Could you use a hole punch to punch a hole through the windings (in one corner of the card) to essentially disable the contact-less payment option (forcing you to use the chip)?
Possible.
A tiny drill would on the coil would do it.
Tried and tested, works fine. Another option is microwaving the card but that may damage the smart card chip too.
You can sometimes see the coil, if the card doesn;t have dark in k colours, by shining a bright light through it. The wire is very thin, so a pin in the right place would do it.
Please note that bank cards are not your property, but the bank's. Messing with them may cause them to be not amused.
Perhaps in your country but certainly not in Australia.
You can sometimes see the coil, if the card doesn;t have dark in k colours, by shining a bright light through it. The wire is very thin, so a pin in the right place would do it.
Around here we have paper ones for use on the metro. You can peel the layers apart and see all the inner workings.
Maybe I can find one that I don't need.
Edit: Here you go...
(the last one is quite high res if you view it separately).
For comparison, here is an X-Ray of a security access control Prox card.
Fraser
For comparison, here is an X-Ray of a security access control Prox card.
Fraser
Judging by the amount of wire, that's a 125khz one
Mike,
I cannot be certain as I do not recall the system it was designed for.
I thought it had a lot of turns on the coil as well, but then thought the turns were on a former of some sort that obscured the required detail, so I cannot be certain. The fact that a former is used would suggest many turns though.
Fraser
Could it be that you can have more than one chip inside them? There's space for three.
Nice little bridge at top left.
Edit: And from the other side...
My shwmbo bought some of these for a recent trip through asia.
Just tested it with my phone. Works quite well can't read the credit card when its in the sleeve
Here in Japan where NFC cards have been used for trains and payments for 15 years now, you can get these at any dollar store. I use them to pad between my NFC cards so one side of my wallet is for the train and the other side is for payments without interference