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RFID blocking?

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BobbyBubblehead

Member
Joined
Jan 29, 2009
So I just did a little experiment blocking my bank card RFID capabilities.

I used some ferrite polymer sheet first and it attenuated the signal and made it harder to read with just a 1mm sheet between the card and scanner.
then I tried the card wrapped both sides and it blocked the RFID 90% of the time.

then I tried some foil wrap used commonly in electronic cables etc. which was far more effective and proved impossible to read the RFID tag.

so is this multi million dollar market for RFID blocking wallets etc just an exploitative method of getting the security conscious and technophobic sector of the community to part with premium cash for a not so premium solution?

your thoughts please... tinfoil hat optional :D
 

Evilsizer

Senior Forum Spammer
Joined
Jun 6, 2002
well i dont know what they charge for these wallets that block the RFID chip from being read. it is really nothing new about this, the same principal as a faraday cage. though faraday cages are grounded so as the signal hits it, it is then going to the ground so it never reaches the RFID or your cell phone or anything that uses radio frequencies.

having a faraday cage would also be a good idea if you have walkies or portable radios you want to protect in case of a EMP. though i would say that you need a insulator between the device/chip from the cage. if you had it directly touching the cage it would be a mute point since the energy would still reach the chip and fry it, when talking about an EMP. the Foil is more then likely thin plastic so that is your insulator and then coated with a liquid or spay aluminum coating.

i cant say its the same thing as this but if you watch the full video and get to around 6:30 when they drop aluminum into the magnetic field.

Aluminum has interesting properties like that for shielding and in magnetic fields, eddy currents. not many realize this but they have magnetic brakes on roller coasters, the aluminum bar is attached to the coaster. then as it reaches a certain point on the track it reaches a set of magents on both rails where the wheels are. the eddy current from the alu bar passing through the field cases the coaster to slow down. if something like this was used on cars there would be no friction/aka brake wear and tear. as well as the side benefit you could still steer the car as if it had ABS, such as when you slam on the brakes to slow down and steer to avoid something.
 
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BobbyBubblehead

BobbyBubblehead

Member
Joined
Jan 29, 2009
I'm with you on the whole of that. Left over materials where from messing about making grounded, semi floating and floating Shields.

On the lines of a grounded Faraday cage... What could you use to absorb the energy around a shield if the transmitter was higher powered.

I like the idea of this simple led rfid scan indicator... Though I'm not so sure he lists the capacitor values he used.
http://mods-n-hacks.wonderhowto.com...r-detector-and-make-custom-rfid-tags-0138673/
 

Dolk

I once overclocked an Intel
Joined
Mar 3, 2008
Wait this is an actual thing? I can't image that someone could actually pick up my RFID code on my card. Anyone have any papers that show people successfully snooping a card off a chip?
 
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BobbyBubblehead

BobbyBubblehead

Member
Joined
Jan 29, 2009
You can get credit card rfid and passport rfid readers on Google play using nfc on your tablet or phone.
In principle the more power your scanners antenna the further away you can read the chip :D

Edit: card test by bitropy. To read your credit card.
ReadID by inno valor. To read your epassport.

Just Google play :)

EDIT2: happened to my partners company credit card at the airport. Transaction Fleece Successful :-/
 
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Evilsizer

Senior Forum Spammer
Joined
Jun 6, 2002
well, the chip on credit cards, is RFID.
http://www.startribune.com/alexander-how-safe-are-chip-based-credit-cards/246054421/

now it has been in use over seas since the 80's or so, its nothing new. now they have had RFID reads for a while now over there, it was only a matter of time before they got to the US. Some stores have just old "strip" readers still and some have one withs both for RFID, target has cards with no "strip" just the RFID chip. that means that once the credit card reader sees the RFID "id" it finds you account info by that and charges that way. Since no two RFID chips have the same "ID" then there i no way someone could gain access to you card. they can though make devices that when it goes to give RFID info if it wast he actual ship, it either can wait to sense power or just auto sends RFID info since its powered on all the time.

Dolk, not being mean but you dont seem to know how RFID works. to keep it simple think of it like wireless battier charging, there is a device in the reader that transmit power for the chip to power up and send its info to the reader. he is right the more powerful the reader the farther away to read the info.


Back to your question, it doesnt matter how high powered the transmitter is, the Faraday cage sends the signal to the ground. as it surrounds the device/devices, which is why some type of insulator is needed between your device/cards and the cage. as to not make contact so that the signal could get in, in the first place. in break or connection to the cage allows the signal inside the cage which then defeats its purpose of making sure the signal doesn't get in. another similar relation to the faraday cage is also a lighting rod, since the lighting bolt is electricity it goes down the path it has which is a rod that has been grounded. since its insulated from the rest of the building the electricity(simplifying for relation to the Faraday cage consider it like the signal) has only one path to take, down the rod to the ground. no signal is getting in unless its broken or something from inside is making contact with the cage.
 

Dolk

I once overclocked an Intel
Joined
Mar 3, 2008
Alright, wo there. Let me just pull out the title to my thesis: "MR4RF: Mem-device with Impedance and their usage with Impedance matching networks for passive RFID Tags in the UHF".

I worked with RFID technology for 3years. I also researched the low level interaction of chips and their ability to be read vs power/distance/impedance. I am one of the first research students to show off how mem-devices can be used in the UHF area.

Now than, why do I find this a bit unbelievable? Its the fact that a passive RFID tag that should have a high level of encryption, can be read from a great distance. Can hackers figure out the technology in time so that they can take advantage of exploits? Yes. How long depends on the security ability. Its also difficult to measure an RFID tag if its antenna is not creating a strong impedance match to the host antenna. I can see how in an airport/mall or the like gives a high probability that a reader could pick up a card here or there, but it should be a very low number 1/1000 or so (educated guess). After taking in the ID of the tag, you will have to decrypt it, at least should have to.

The reason I asked for articles and proof is because I don't see how this could be a very successful hacking/thieving route for criminals. These chips should very well designed toward security, and so I have educated assumptions on the design of the chip. Those are: 1) The chip's antenna has a narrow band impedance for close UHF reads. 2) The payload saved on the RFID tag is encrypted with some sort of high end security but needs to be simple for RFID Tag to not be duped (256 - 512 bit is possible in this range).

So I'll ask again... Wat?
 
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BobbyBubblehead

BobbyBubblehead

Member
Joined
Jan 29, 2009
I do know now there was over a million cases of rfid fraud in the UK in 2014 costing 300 million odd.
Which suggests the banks here allow weak protocol and void the need to respond with a pin code because they make a several hundred fold profit from the insurance. :sly:
Then pass the premium on to the consumer :-/

How it is in the U.S. I don't know.

http://www.theukcardsassociation.org.uk/plastic_fraud_figures/

I'll keep on researching as I find time :)
 
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Dolk

I once overclocked an Intel
Joined
Mar 3, 2008
I do know now there was over a million cases of rfid fraud in the UK in 2014 costing 300 million odd.
Which suggests the banks here allow weak protocol and void the need to respond with a pin code because they make a several hundred fold profit from the insurance. :sly:
Then pass the premium on to the consumer :-/

How it is in the U.S. I don't know.

http://www.theukcardsassociation.org.uk/plastic_fraud_figures/

I'll keep on researching as I find time :)

The numbers show that there is an actual decline in card related theft when it attributes to scanners. Card ID, Fraud/Stolen, and skimmed have all declined over the years (my guess in tribute to better RFID security). All the other instances can be attributed to websites being hacked or people picking up lost cards or stealing the physical card itself.
 

Alaric

New Member
Joined
Dec 4, 2011
Location
Satan's Colon, US
Went with a friend to Wally World just before Christmas. She was going to get 3 gift cards as presents from the three huge, rotating racks covered with "new" gift cards. She spent 30 minutes with a cashier trying to find one that didn't register as already used and drained. The only ones in the store that hadn't been loaded and used already were behind the customer service counter in a small metal box. The manager's response was "That's why we have tax write offs." There were thousands of useless cards on the displays. When asked if he was going to call the police , he said "Let corporate handle it".
 

Evilsizer

Senior Forum Spammer
Joined
Jun 6, 2002
Alright, wo there. Let me just pull out the title to my thesis: "MR4RF: Mem-device with Impedance and their usage with Impedance matching networks for passive RFID Tags in the UHF".

I worked with RFID technology for 3years. I also researched the low level interaction of chips and their ability to be read vs power/distance/impedance. I am one of the first research students to show off how mem-devices can be used in the UHF area.

Now than, why do I find this a bit unbelievable? Its the fact that a passive RFID tag that should have a high level of encryption, can be read from a great distance. Can hackers figure out the technology in time so that they can take advantage of exploits? Yes. How long depends on the security ability. Its also difficult to measure an RFID tag if its antenna is not creating a strong impedance match to the host antenna. I can see how in an airport/mall or the like gives a high probability that a reader could pick up a card here or there, but it should be a very low number 1/1000 or so (educated guess). After taking in the ID of the tag, you will have to decrypt it, at least should have to.

The reason I asked for articles and proof is because I don't see how this could be a very successful hacking/thieving route for criminals. These chips should very well designed toward security, and so I have educated assumptions on the design of the chip. Those are: 1) The chip's antenna has a narrow band impedance for close UHF reads. 2) The payload saved on the RFID tag is encrypted with some sort of high end security but needs to be simple for RFID Tag to not be duped (256 - 512 bit is possible in this range).

So I'll ask again... Wat?
RFID on credit cards has been in use in Europe since the 80's, Back then encryption was a pipe dream. They had to come up with other ways that back then were harder then they are now. You want articles these are just a few i found on google in the matter of a few minutes.
http://hackaday.com/2013/11/03/rfid-reader-snoops-cards-from-3-feet-away/
https://threatpost.com/long-range-rfid-hacking-tool-to-be-released-at-black-hat/101448/
http://www.digitaltrends.com/cool-t...heft-protection-is-as-simple-as-an-on-button/
http://www.dailymail.co.uk/sciencet...sy-steal-credit-card-numbers-air-SECONDS.html
http://www.tech-faq.com/rfid-skimmer.html
http://abc7chicago.com/technology/secretly-swiped-your-account-numbers-taken-out-of-thin-air/510920/

i found this project which i thought was interesting
http://www.instructables.com/id/A-Universal-RFID-Key/

bobby, what you posted earlier makes me think it was this with a LED built on so you can see if someone is trying to use a RFID reader.
https://hackaday.com/2008/11/11/scratch-built-rfid-tags/
as far as the cap, its hard to say its value but i think its being used as a frequency filter since its tied to ground.
 

Alaric

New Member
Joined
Dec 4, 2011
Location
Satan's Colon, US
They scan the cards and load and activate them with computers I imagine. My point was that's a lot of money, that translates directly to consumer prices eventually, as well a tax shrotfalls.
 
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BobbyBubblehead

BobbyBubblehead

Member
Joined
Jan 29, 2009
So drawing all of this back to conclusion here's a couple of straight questions I'd like opinions on.

1. Is the rfid blocking market valid in terms of risk or merely a money spin for the paranoid.

2. Given the cost of low tech aluminium foil is it a bonus gesture to incorporate it into designs for carrying cards e.g. wallets etc.

And as a spin off wouldn't it be cool to manufacture an rfid card that was independently powered to sound an alarm when a scan is in progress. (if not for the fun of punching out some technothief and taking their expensive reader to sell off... Err, I mean so you can alert the appropriate authorities) :D
 

Evilsizer

Senior Forum Spammer
Joined
Jun 6, 2002
So drawing all of this back to conclusion here's a couple of straight questions I'd like opinions on.

1. Is the rfid blocking market valid in terms of risk or merely a money spin for the paranoid.

2. Given the cost of low tech aluminium foil is it a bonus gesture to incorporate it into designs for carrying cards e.g. wallets etc.

And as a spin off wouldn't it be cool to manufacture an rfid card that was independently powered to sound an alarm when a scan is in progress. (if not for the fun of punching out some technothief and taking their expensive reader to sell off... Err, I mean so you can alert the appropriate authorities) :D

1: yes to both, if they try to tell you its takes of lot of research to block the signal they are full of it. its a money grab to see how much more you will pay for it.

2:as long as it blocks the signal for a reasonable cost but what is reasonable? some people pay more based on looks more then function, if its cheap, you are ok with how it looks, and it works then buy it. maybe you have two layers of cloth one on the out side with the a woven alu in it to block the signal or a layer of alu foil between both pieces of cloth. it still takes someone working a sewing machine or doing it by hand to make it. how much you think their time is worth is how much your willing to pay, wish this also ties into looks.

well to sound an alarm you might as well carry a device that detects these readers and makes a sound. if you were to tring to use the in coming "power" from the reader you may not have enough to make it produce sound. its really a matter of how much you want to put into this and if your going to go to conventions just to see how much of this actually happens. as some like the hacker conventions, i have read it is more then suggested by alot of people to leave any CC's in your hotel and only carry cash for this reason of old CC and CC-RFID readers. with ever evolving tech, these things will get smaller and smaller, as well as being able to store more data. granted storing text doesnt take much storage but when talking about these devices. we could say some have maybe 16/32mb of ram built in maybe more. its hard to know exactly how much storage these things have. even so with that low amount you have to possibility to store 10k-20k in cc/cc-rfid info maybe even more.
 
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BobbyBubblehead

BobbyBubblehead

Member
Joined
Jan 29, 2009
DSC_0353.JPG

Well this self adhesive foil wrap from the electronics store used to shield cables etc. costs a couple of pounds for a fifty meter roll.
In an instance where you were to produce a leather wallet you'd stick a strip to the leather front and back pieces then the fabric lining covers it and the cards will be seated tightly in-between. It's so cheap a solution that it adds an negligible few pence to the design.

Seems to be effective from a low powered reader.

If you implemented a layer of ferrite polymer resin, then foil and used copper mesh for the outer layer it would attenuate the signal further but the cost and bulk would pose problematic. Price of ferrite polymer has rocketed over the past couple of years... What cost 8 pounds for an A4 sheets now costs 30 or 40 pounds :-/