RFID defensive technologies for one's personal cards, passport, etc. - Page 1
Forum section: electronics / general

author: cdev
author_rank: Super Contributor
timestamp: December 30, 2020, 03:22:39 am
content: For many years Ive noticed that some cards seem to contain RFID tags, often without any warning to the user. Now some cards are being labeled as having these tags, but in fact they are not new. I'm not talking about the ones you know you have.So now a bunch of new devices and wallets have come out purporting to shield your cards from the burst of RF that makes them give up their data. The only problem is, it seems likely to only work at that specific frequency and no others.Just FYI, anything conductive will work as well as some other materials that are less conductive. An ESD bag or even just a corner of an ESD bag, if folder will block almost anything RFIDable including (most? Many?) RFID tags. The old reliable aluminum foil - if its completely enclosing the cards - and making contact at all edges- will block 100% of all RFID devices but its not as durable as one would like, also it makes that telltale crinkly sound.(/humor)This is one that seems perhaps to be based on better science than most. However it only blocks this specific kind of tag. Also, how could it possibly be 100% reliable? Barring a complete enclosure, it seems doubtful that anything could be, if the power was high enough.That said, I recently stumbled acrossSkimSure(tm)

author: Whales
author_rank: Super Contributor
timestamp: December 30, 2020, 04:50:33 am
content: Aluminium foil isn't 100%, I've managed to scan cards through it. NSW Opal card (so probably not a special high-power or long range reader).

author: Raj
author_rank: Frequent Contributor
timestamp: December 30, 2020, 01:04:09 pm
content: You know, you can tell the bank to ignore transaction attempts made using scans done to your card's wireless.

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 30, 2020, 08:49:54 pm
content: Quote from: Raj on December 30, 2020, 01:04:09 pmYou can disable contactless payments altogether, but I don't think that's only what the OP was concerned about. Even without this, you can read a certain amount of data. In particular, you can read the card number and expiry date. I have an app on my phone that does exactly that, and it works. It doesn't give the PIN code of course, but it does give you the number of failed attempts if any. I haven't looked that up, so I'm not sure what else you can read.Now NFC only works at very short ranges. Even with extended range readers, reading anything further than ~10 cm (and reasonably parallel to the reader's coil) is very challenging, so I wouldn't fret too much about it. And yes, if you use some shielding, even if not 100% effective, it will reduce the usable range even further.

author: Haenk
author_rank: Super Contributor
timestamp: December 31, 2020, 07:51:10 am
content: Quote from: SiliconWizard on December 30, 2020, 08:49:54 pmThe danger is quite real. I remember a video from Russia (it's been a couple of years now) where they demonstrated directly charging credit cards in peoples pocket in a subway, packed with people. It's also possible to read RFID from way more than 10cm, a couple of meters should be possible even for simple credit cards (if you are able to hide a larger antenna); one meter with standard equipment...

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 31, 2020, 04:44:50 pm
content: Quote from: Haenk on December 31, 2020, 07:51:10 amI do not buy that. Please give evidence. It's not just plain RFID, it's NFC (with a min rate of 106 kbits/s) and there is no way you can read NFC tags at one meter with "standard" equipment. Even with advanced gear, it will be pretty challenging.Do not hesitate to experiment and report back, though. Meanwhile, I call bullshit outside maybe of experiments in lab with very advanced techniques and hours of work.