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I know that for credit cards with RFID there are solutions to prevent unauthorized parties from reading the data for fraudulent purposes

If I know that my card 99% of the time is only going to do payments via chip, how can I shield the mag stripe so it can't be read? Tampering or removing it is not an option as in some stores in my country and mostly all of US' stores the mag stripe is still used

Is there something equivalent for the mag stripe as there is for RFID (put a thin foil of lead in a cardboard sleeve for your credit cards)

I was thinking of putting a piece of aluminum in the portion of the mag stripe that will not go into chip readers but since aluminum is a non magnetic material I'm wondering if it'll work

Jose R
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  • This may not help you in any way since it requires enough prescision, holding it still and sub-centimeter proximity to be done. At that point, someone could also just take a picture of your card as the magstripe contains the same information as the text on the card. – John Keates Aug 20 '17 at 01:45
  • @JohnKeates thanks. some of the newer credit cards do not have the cardholder's name printed on it physically so I think there is an advantage here to be gained here – Jose R Aug 20 '17 at 02:17
  • @JohnKeates I'm also trying to slow down or notice if "skimming" (if that is the correct term, sorry I'm not well versed in this topic) has happened. E.g. Noticing if the EMI tape was removed without a valid reason – Jose R Aug 20 '17 at 02:24
  • I think you may actually have additional effect by making the card too thick to fit inside a cardreader, maybe using some sort of sleeve. Edit: that would be problematic for chip readers too, so no go on that one. – John Keates Aug 20 '17 at 03:09
  • Thanks John my initial thought was to only cover the stripe on the portion that doesn't go into the reader so it would be kind of trying to read a stripe cut in half – Jose R Aug 20 '17 at 03:31

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You should look for EMI foil tape. It is designed for use as shielding in electronic circuits to minimise unwanted electromagnetic emissions. Avoid the stuff for sale on Amazon and eBay; stick to reputable electronics vendors such as Mouser, DigiKey, Farnell, RS Components, etc.

Another option is to wipe the magstripe completely, then set up and carry a prepay card as a backup for cases where you actually require the magstripe.

Polynomial
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  • Keep in mind that it might interfere with radio transmissions as well. – John Keates Aug 20 '17 at 01:48
  • @JohnKeates thanks my cards perhaps have rfid -which I highly doubt- but in my country we're years away from accepting contactless payments – Jose R Aug 20 '17 at 02:26
  • Ah yes, pure chip based systems are still used in some countries. I guess EMI tape would be the way to go. You can get wide rolls that will block both NFC and magnetic readers at the same time. Getting one with a foil type that wrinkles will help detect people trying to get it off – John Keates Aug 20 '17 at 03:11
  • @JohnKeates thanks by any chance do you have a link to a product page similar to the one you're describing that you could post, please ? – Jose R Aug 20 '17 at 03:39
  • @JohnKeates The tape would only block what's immediately under it, and contactless cards run the antenna across the whole card. You could also present the opposite side to where the tape was applied if it does cause problems, although I doubt it would. – Polynomial Aug 20 '17 at 10:08
  • @JoseR I'd prefer not to give a direct product link because links tend to age poorly. Search for "EMI tape" on Mouser, Digi-Key, Farnell, RS Components, or a similar mainstream electronics site. Filter down based on your size and quantity requirements. – Polynomial Aug 20 '17 at 10:10
  • @JohnKeates thanks, since this is more complicated than I thought I will be testing this solution after I return from a business trip. I'm accepting this as the answer as it has consensus from you two. – Jose R Aug 20 '17 at 15:20
  • When you have the chance to test, by all means, let us know how it went! @Polynomial while it would not cover the whole NFC antenna, it would probably reduce the power transfer, and hopefully to the point where the chip won't have enough power to work. – John Keates Aug 20 '17 at 15:22