Just found out I can read my debit card number from the outside of my wallet with my Flipper's NFC reader. 🥴
It's a short distance (under half an inch), but it suggests not setting my wallet down on untrusted surfaces (a good idea generally) and/or lining the folds of my wallet with aluminum foil. Which is cheap - I'm going to try that now.
Likewise with my phone, but that has to be unlocked, so I think it's a bit lower risk.
#Flipper #FlipperZero #NFC / https://flipperzero.one/
@digitalfox here's a tip: the easiest and most effective way to prevent an NFC card from reading is to put another NFC card (preferably but not necessarily of the same type) right next to it
-F
@Felthry Noted!
Whenever my credit card expires, the refresh will likely have NFC, so at that point I'll have two nearly-identical NFC cards directly overlapping each other. And I'll also do the foil - it doesn't seem like there's any harm in doing both.
@digitalfox nah, no harm in it at all, just not as foolproof as a lot of people think
any old NFC card will do as the dummy one, also! So if you want, you can just order a blank one (i don't think it needs to have any data on it to work, but you can put something on it too)
or if you have a hotel keycard you forgot to return at some point, if it's the nfc type it'll work
-F
@Felthry Ah, noted.
I have some Mifare Classic tags (marketed as Samsung TecTiles); unfortunately, it seems to be 50/50 on whether it overrides the bank card, probably due to the smaller size. I may look into something more thorough in the future.
@digitalfox That could also be that mifare and whatever bank cards use are just too different--it shouldn't *override* it, the reader should fail to read at all
if it's able to read one of the two at random that probably means it's either detecting the mifare protocol or the bank card protocol and successfully communicating with just one card? i don't know honestly we've never tried this with two different types of card
-F
@digitalfox there's no system in the standard for getting only one thing to respond other than "only have one thing within range at a time", so if there are two things they'll both try to talk over each other and just confuse everything, it's impossible to get a read in that situation whereas it's quite possible to get a read through a foil lining with a strong enough transmitter and sensitive enough receiver
-F