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SFandH
Elite Nomad
Posts: 7215
Registered: 8-5-2011
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It would be interesting to know exactly what information is contained on the chips.
I guess I could buy a reader.
UHF Handheld RFID Reader, Order Now!
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Bruce R Leech
Elite Nomad
Posts: 6796
Registered: 9-20-2004
Location: Ensenada formerly Mulege
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Mood: A lot cooler than Mulege
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try this
https://www.youtube.com/watch?feature=player_embedded&v=...
Bruce R Leech
Ensenada
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Bruce R Leech
Elite Nomad
Posts: 6796
Registered: 9-20-2004
Location: Ensenada formerly Mulege
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Mood: A lot cooler than Mulege
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some readers can work from up to 12 feet away and can write info on your card also
Bruce R Leech
Ensenada
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DavidE
Ultra Nomad
Posts: 3814
Registered: 12-1-2003
Location: Baja California México
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Mood: 'At home we demand facts and get them. In Mexico one subsists on rumor and never demands anything.' Charles Flandrau,
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I'd like to clone Carlos Slims' black American Express card on my hotel room access card. New Bugatti? No problemo! Hire a 175' schooner for an around
the world trip? No problemo.
I could rig up a 9 volt thyristor fired pulse that would cause the magic black smoke to rise from any reader, counterfeit or no.
Actually, I had a nice talk with Wells Fargo. They are clued that an attempt to secure 1st class airfare to Damascus for 12, would more than likely
not be legit. Same for one ATM withdrawal in Montpelier at 9:00AM and another in Tijuana at 1:00PM. If I purchase something online, it is sent to my
PO box in Chula Vista. Otherwise it's all mid-Baja California usage.
A Lot To See And A Lot To Do
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elbeau
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Posts: 256
Registered: 3-2-2011
Location: Austin, TX
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| Quote: | Originally posted by MitchMan
elbeau,
Just how far away from a reader (inches, feet?) can a credit card be read in most cases? |
That's a trickier question than you may think. RFID chips like those in credit cards do not have any internal power source like a battery. They get
powered by an electrical field that is generally produced by the same device that listens for the RFID transmission but there's no reason that the
RFID reader can't be decoupled from the device producing the electrical field.
If you are purely interested in the "read range" of the credit card regardless of the electrical field range powering the tag, then very long ranges
can be achieved. All you need is a sensitive antenna. When a credit card comes within the electric field produced by an RFID credit card machine it
starts broadcasting your credit card information. People assume that only the nearby credit card machine can pick up the signal that is being
broadcast but this is not true. All you have to do is point a decent antenna towards a legitimate RFID credit card machine and you will see people's
credit card numbers when they use their cards.
So, to answer your question more directly, the power source creating the electric field that powers the RFID chip must be fairly close to the card but
the antenna picking up the signal can be far away.
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elbeau
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Posts: 256
Registered: 3-2-2011
Location: Austin, TX
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| Quote: | Originally posted by Bruce R Leech
some readers can work from up to 12 feet away and can write info on your card also |
It is true that almost all passive RFID chips like the ones in credit cards support 2-way communication and that is what blows my mind about the
unencrypted implementations. You could make the whole implementation perfectly safe by doing asymmetric encryption. Let me explain:
Right now your credit card's RFID chip broadcasts your actual credit card number when the RFID reader powers the chip. Instead of doing this the
reader should first contact the credit card company and obtain a token piece of text to send to the tag. The tag could then append your credit card
number to the random text, encrypt the result, and broadcast the encrypted text instead of broadcasting your credit card number. The reader never
needs to see your unencrypted number, it can just pass the encrypted message to the bank. The bank can decrypt the message to get your credit card
number, check that the token is valid, and check that the token came from the machine it was initially issued to.
That may sound a little complicated but it's very easy to implement and is commonly used in other applications. The result is that the RFID works
just the same for the consumer but your information is never broadcast out unencrypted. The merchant can't even see your credit card number which
makes it much more secure than swiping your card.
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DavidE
Ultra Nomad
Posts: 3814
Registered: 12-1-2003
Location: Baja California México
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Mood: 'At home we demand facts and get them. In Mexico one subsists on rumor and never demands anything.' Charles Flandrau,
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When an unauthorized reader queries the chip let an unauthorized transponder reply with a 10 watt full course reply. Enough to fuse their circuitry.
A Lot To See And A Lot To Do
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chuckie
Elite Nomad
Posts: 6082
Registered: 2-20-2012
Location: Kansas Prairies
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Mood: Weary
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Do we get the transponder on Ebay, how big is it, does it fit in a wallet?
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elbeau
Nomad
Posts: 256
Registered: 3-2-2011
Location: Austin, TX
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| Quote: | Originally posted by DavidE
When an unauthorized reader queries the chip let an unauthorized transponder reply with a 10 watt full course reply. Enough to fuse their circuitry.
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That's also very true. It doesn't take much effort to fry the chips. It's not uncommon for passive tags to fry randomly with normal use.
Intentionally frying them is very easy.
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elbeau
Nomad
Posts: 256
Registered: 3-2-2011
Location: Austin, TX
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| Quote: | Originally posted by chuckie
Do we get the transponder on Ebay, how big is it, does it fit in a wallet? |
Umm...I'm starting to worry about why you want to know 
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MitchMan
Super Nomad
Posts: 1856
Registered: 3-9-2009
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Thanks, elbeau.
Let me see if I understand. It sounds as though the credit card's RFID chip is capable of being empowered with electromagnetic energy
(electromagnetic field) from an external source (such as an RFID reader) and then it, the credit card's RFID chip, then broadcasts electromagnetic
energy waves that contain the credit card info.
It sounds like the credit card has to be close enough to the reader to be within the readers energizing field. Right? Also, once the credit card
RFID chip is energized and broadcasting, such broadcasted info can be picked up by an adequately "sensitive' antenna that could be far away, right?
All this, if I am correct, sounds like the RFID reader needs to be close to the credit card, but the antenna picking up the info
broadcast by the energized credit card RFID chip can be much farther away from the credit card than the reader, right?
Lastly, it sounds like the RFID reader can be as far away from the RFID credit card as 12 feet.
Man, if I am right about this, that is absolutely and totally unacceptable.
elbeau, the method you described to provide security by employing the "token" text (or "key") coupled with encryption should be the only way this
thing is implemented. Seems similar to the way that networks and password routines work.
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MrBillM
Platinum Nomad
Posts: 21656
Registered: 8-20-2003
Location: Out and About
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Mood: It's a Zip-a-Dee-Doo-Dah Day
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EBay ?
http://www.ebay.com/sch/i.html?_nkw=RFID+reader
Amazon ?
http://www.amazon.com/s?ie=UTF8&page=1&rh=i%3Aaps%2C...
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elbeau
Nomad
Posts: 256
Registered: 3-2-2011
Location: Austin, TX
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| Quote: | Originally posted by MitchMan
Thanks, elbeau.
Let me see if I understand. It sounds as though the credit card's RFID chip is capable of being empowered with electromagnetic energy
(electromagnetic field) from an external source (such as an RFID reader) and then it, the credit card's RFID chip, then broadcasts electromagnetic
energy waves that contain the credit card info.
It sounds like the credit card has to be close enough to the reader to be within the readers energizing field. Right? Also, once the credit card
RFID chip is energized and broadcasting, such broadcasted info can be picked up by an adequately "sensitive' antenna that could be far away, right?
All this, if I am correct, sounds like the RFID reader needs to be close to the credit card, but the antenna picking up the info
broadcast by the energized credit card RFID chip can be much farther away from the credit card than the reader, right?
Lastly, it sounds like the RFID reader can be as far away from the RFID credit card as 12 feet.
Man, if I am right about this, that is absolutely and totally unacceptable.
elbeau, the method you described to provide security by employing the "token" text (or "key") coupled with encryption should be the only way this
thing is implemented. Seems similar to the way that networks and password routines work. |
You are correct about how it works, but the reader can be much farther away than 12 feet. The electric field size can't get much larger than that
without breaking a lot of EM emission regulations, but the antenna can be much farther away.
Yes, the encryption protocols are commonly used in networking and are not specific to RFID implementations.
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elbeau
Nomad
Posts: 256
Registered: 3-2-2011
Location: Austin, TX
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| Quote: | Originally posted by elbeau
You are correct about how it works, but the reader can be much farther away than 12 feet. The electric field size can't get much larger than that
without breaking a lot of EM emission regulations, but the antenna can be much farther away. |
I just re-read what I wrote and need to clarify that the "reader" is the device reading the signal from the antenna, not the device creating the
electric field, so the reader/antenna can be much farther away than 12 feet, but the device creating the electric field needs to be within several
feet of the RFID tag.
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MitchMan
Super Nomad
Posts: 1856
Registered: 3-9-2009
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Thanks again, elbeau. That last post with clarification was invaluable.
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dasubergeek
Senior Nomad
Posts: 694
Registered: 8-17-2013
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All this tin-foil hat business. Look at your credit card. Find the little radio signal icon. Smash it with a hammer (try not to hit your magnetic
strip, because that would be bad).
Done and done.
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