The Lemon Fool

I have a Contactless Cashback Barclaycard credit card, old style nothing 'moderne'.

I badly need to disable its RFID, it being impossible to get a non Contactless Barclaycard. I thought I had succeeded, but a trip to Aldi this morning - to buy groceries and test the card - shows I failed.

At first it seemed to work (that is NOT work) but I persisted and unfortunately the transaction went through "CONTACTLESS". So, back to the drawing board.

I originally scored all around the chip contact area on the front of the card with a sharp knife. Further, using the old expired card I had bent the old card along the side seams of the chip contact area, revealing two fine copper wires. One appearing to go to the top left and one to the top right of the chip contact area - seeming to confirm I was on the right track with my scoring technique on the current card.

But, so far, it hasn't worked!

Why not? Because I haven't managed to cut through both wires - despite them being very fine and easily exposed to view by bending back the old card as above? Could it be that the aerial has been severed from the chip but nevertheless the chip is still sensitive enough to work directly with remaining stubs? (Yet I thought the aerial needed to supply power to the chip wirelessly, which I can't see working if the aerial loop has been severed)

My only new thought is to try gluing aluminium foil to the rear of the card (but might this enhance the aerial?) and revisiting Aldi. This could go on for some time...

Does anyone here have any direct experience of successfully disabling RFID on such a card? If so, can they advise?

TIA

not sure if it works but this guy butchered it
https://www.reddit.com/r/privacy/commen ... edit_card/

...LOL.

Sadly, from that description, the situation with his debit card appears identical to that with my Barclaycard credit card.

XFool wrote:I badly need to disable its RFID

Why?

Rob

I have no interest in doing this.

However, a search engine provided this link.
https://www.instructables.com/Disabling ... bit-Cards/
Apparently, with an X-ray of the card, you can identify where to cut. In the case mentioned, removing a corner of the card worked.

If you want to see what's inside a contactless card, watch this....

BBC iPlayer wrote:Hannah Fry dissolves a bank card to reveal the hidden technology inside.

https://www.bbc.co.uk/programmes/p0dcy7nm

Breelander wrote:If you want to see what's inside a contactless card, watch this....

BBC iPlayer wrote:Hannah Fry dissolves a bank card to reveal the hidden technology inside.

https://www.bbc.co.uk/programmes/p0dcy7nm

saw that a while ago
well worth a look

Urbandreamer wrote:I have no interest in doing this.

However, a search engine provided this link.
https://www.instructables.com/Disabling ... bit-Cards/
Apparently, with an X-ray of the card, you can identify where to cut. In the case mentioned, removing a corner of the card worked.

"Since I have access to a micro-CT scanner at the University of Huddersfield Centre for Precision Technologies, I thought I'd put my card in the machine, take a 2d xray still and allow myself to find the quickest and easiest way to disable it."

That sounds like a useful bit of kit for these complicated days.

The cut off at corner approach, according to a posted comment, may cause problems at an ATM. This shouldn't bother me as it is a credit card and I never use it at ATMs. Still, be warned.

Meanwhile, I have discovered the ideal tool for 'chip gouging', a sharp metal tooth pick. It fits perfectly into the channel between chip contact area and plastic card and permits reliable, steady, concentrated, gouging. Using a very high powered lens, copper was sighted at the top two segments of the contact area - agreeing with my observations on the destroyed old credit card. Further gouging and the use of the single lens 'microscope' appears to confirm these have now been gouged through.

My card reader confirms Chip & PIN still working. Unfortunately, as I don't currently have a smart phone, I can't determine its RFID status, so another trip to Aldi or elsewhere is called for. I will report results when available.

Meanwhile, negotiations with Transport for London are ongoing.

XFool wrote:I originally scored all around the chip contact area on the front of the card with a sharp knife.

I think you're in the wrong place. Try cutting a few mm into the bottom edge of the card - the antenna forms a loop close to the edge of the card. Cut with sharp knife, don't score.

MyNameIsUrl wrote:

XFool wrote:I originally scored all around the chip contact area on the front of the card with a sharp knife.

I think you're in the wrong place. Try cutting a few mm into the bottom edge of the card - the antenna forms a loop close to the edge of the card. Cut with sharp knife, don't score.

But the aerial has to connect to the chip and the RFID chip is combined with the Chip & PIN chip, there is only one chip per card. So isolating the chip from its surroundings ought to work and, as per my later post, I have now definitely scored through two pieces of copper at the top of the chip connector. I suspect my first attempt with the knife didn't go far enough in.

But I will have to wait 'til next time I go shopping to see if it has now been a success.

XFool wrote:I have a Contactless Cashback Barclaycard credit card, old style nothing 'moderne'.

I badly need to disable its RFID, it being impossible to get a non Contactless Barclaycard.

Perversely Barclays allow customers to turn off contactless on their debit cards but not their credit cards.

Nice customer service by Barclays.

While I can't see a reason to disable contactless, I can't understand why the likes of Barclaycard don't offer the option.

It's not a matter of different hardware, the chip in a card is actually a small computer running a program. It could be instructed to not use RFID.

Likewise, the POS has to check if the card is allowed to transact, it would be simple to communicate, either from the card or POS that it's a contactless transaction associated with the given account and block accordingly. That's clearly the way MBNA do it, as you can turn on or off contactless yourself, without using the card.

https://www.mbna.co.uk/online-services/ ... &ccconthlp

Contactless transactions- freeze contactless transactions worldwide. Including digital wallets such as Apple Pay and Google Pay.

It might be worth voting with your wallet, rather than messing around with a scalpel.

Ps, I've been happy with MBNA for decades, but binned Barclaycard when I left Barclays in disgust.

XFool wrote:But the aerial has to connect to the chip and the RFID chip is combined with the Chip & PIN chip, there is only one chip per card. So isolating the chip from its surroundings ought to work and, as per my later post, I have now definitely scored through two pieces of copper at the top of the chip connector. I suspect my first attempt with the knife didn't go far enough in.

At radio frequency, it doesn't need to connect as in be physically touching. RF signals can easily jump small gaps. So if you've cut the wires but the cut ends are only microns apart, the RF signal will go through almost as if there was no cut. You need to make a wider cut to block RF signals - I don't know how wide it needs to be, but if there's no visible gap it's almost certainly not wide enough.

XFool wrote:

MyNameIsUrl wrote:

XFool wrote:I originally scored all around the chip contact area on the front of the card with a sharp knife.

I think you're in the wrong place. Try cutting a few mm into the bottom edge of the card - the antenna forms a loop close to the edge of the card. Cut with sharp knife, don't score.

But the aerial has to connect to the chip and the RFID chip is combined with the Chip & PIN chip, there is only one chip per card. So isolating the chip from its surroundings ought to work and, as per my later post, I have now definitely scored through two pieces of copper at the top of the chip connector. I suspect my first attempt with the knife didn't go far enough in.

But I will have to wait 'til next time I go shopping to see if it has now been a success.

You might be able to see the tracks running from the chip if you put a suitably bright light source behind the card - or have a big enough magnifying glass

XFool wrote:Does anyone here have any direct experience of successfully disabling RFID on such a card? If so, can they advise?

Yes. Twice. As previously reported at viewtopic.php?p=548559#p548559.

You don't need to score all around the chip, just at the sides. That's worked for me. Twice. You also don't have to wait until going to the supermarket to test it, you can get RFID card reader apps on your phone. See link.

...adding my experience (if successful!), it really helps to have a strong lens/microscope to be able to see what is going on.

Again, I would recommend a sharp, metal, dental toothpick as the ideal tool for the job.

XFool wrote:...adding my experience (if successful!), it really helps to have a strong lens/microscope to be able to see what is going on.

Again, I would recommend a sharp, metal, dental toothpick as the ideal tool for the job.

Dental toothpicks are a God-send in this kind of thing; there's no better tool for lifting a leg! (Though you can make two decent approximations out of a decent pair of tweezers )

robbelg wrote:

XFool wrote:I badly need to disable its RFID

Why?

Rob

Safety, security and that thing that our lords and masters want us consumers to believe that we still have, ....what's it called? Oh yes, Freedom of choice.

Given that people often touch their card on the wrong part of the reader, I don't see that sliding your card in and typing four numbers takes much longer.

Steve

PS I have disabled two cards simply by making one or two small cuts with a razor into the card on the short edge that faces you when you slide it in. Simply practise first on a few old expired cards and see if they make a reader go 'ping'.

RFID only works over very short distances. It's more like a modulated transformer than "radio". The card has to be close enough to the reader to take power from it.

You are probably at greater risk with chip and pin, as you are subjecting your pin to unknown machines which could grab your number - or you could be watched.

SteelCamel wrote:

XFool wrote:But the aerial has to connect to the chip and the RFID chip is combined with the Chip & PIN chip, there is only one chip per card. So isolating the chip from its surroundings ought to work and, as per my later post, I have now definitely scored through two pieces of copper at the top of the chip connector. I suspect my first attempt with the knife didn't go far enough in.

At radio frequency, it doesn't need to connect as in be physically touching. RF signals can easily jump small gaps. So if you've cut the wires but the cut ends are only microns apart, the RF signal will go through almost as if there was no cut. You need to make a wider cut to block RF signals - I don't know how wide it needs to be, but if there's no visible gap it's almost certainly not wide enough.

This is almost exactly the answer I was about to post. A small gap at such frequencies is just another way of describing a capacitor, which is a device frequently used in series along the RF signal path for various reasons including decoupling the DC biasing point of one stage of the electronics from the next.

Seems to me like a totally pointless exercise anyway. The interlocutor has to be very close; and anyway the banks are so very keen to promote their stuff that in my experience any fraud of any kind is almost immediately refunded.

C.