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Radio Credit Cards Move Closer
pvt_medic writes "CNN.com has an article about research that some major credit card companies (MasterCard and American Express) are putting into creating 'contactless' credit cards. These are similar to the Speedpass that ExxonMobil has been using for six years. What to people think about the prospect of this more widespread use of RFID? Is this something that will only lead to more credit card fraud, or will it provide more secure means of payment?" (The article comes from the Associated Press.)
The Octopus card is widely used in Hong Kong. Its a stored value card, so its anonymous. It started life in the MTR (the local mass transit system) and has since expanded to convenience stores, Macdonalds, Starbucks, etc.
Two wrongs don't make a right, but three lefts do.
Yeah, and my office building handles much more sensitive data than a CC and it has much more, shall we say, more "mature" technology in the access cards used. I don't think it is that big of a deal. As it is, anyone with rudimentary "Radio Shack skills" can program a magnetic strip for an ordinary non-smart-card CC.
Those that suggest you "dance like no one is watching" really want to see you make a complete fool of yourself.
Basically, the idea is that if both you and the authenticator know the secret password, but you don't want to transmit it, the authenticator sends you some random chunk of data, say message M. You encrypt it using some (presumably one-way) algorithm, using your password as the encryption key to create W. The authenticator also encrypts the same chunk, and, when you send back your W, compares it do his own known-good W. Assuming they match, it means you have the password. The password itself is never sent plaintext.
You seem to be assuming that there is one secret key for the whole system. This would be completely useless, and is obviously not the case. You would need one secret key per person, as I'm sure American Express knows.
The spec has successfully been used by the German transmit authority to curtail fraud in their system.
It uses challenge-response encryption so it is very resistant to "man in the middle" attacks and snooping. Operates on a near-field magnetic-load method of communication.
This means that the main transmitter senses changes in the energy load as a method communication. The RFID tag just gets its power from the magnetic carrier and changes the magnetic load to communicate. This makes it more difficult to snoop than RF because the energy and communication transfer is bound into a closed loop.
One other point, magnetic load technology has a range that is proportional to the antenna. A 18 centimeter antenna has a range of 18 centimenters if it is built correctly. With a fundamental frequency of 13.56Mhz, the theoretical maximum range is 3 meters (16% of wavelength is the maximum range for the near field). This means that you would need a 3 meter (~10 foot) antenna to reach ten feet. People would tend to notice this.
Just some info.
Wrong. RTFA. Consumer gets to make final "accept/reject" on purchase after card is scanned. Also, card includes challenge/response authentication (AMEX at least, MC we aren't told). As the article clearly states, knowing the RFID card number does not give a thief any practical means to use it.
If the merchant accepts cash and credit, there is no apparent difference to me (the consumer) in regards to sticker price; unless the merchant offers a cash discount (since merchant agreements usually prohibit credit charges)
Of course, factoring in the time value of money, it's cheaper for me to buy with credit, since I don't have to actually pay for it for 30-50 days.
Need a Catering Connection
The card is usually passive (without an internal battery) and consists of an antenna and an RFID ASIC (Application Specific Integrated Circuit). During operation, the transmitter sends out an electro-magnetic wave to establish a zone of surveillance. When a card enters this zone, the electromagnetic energy from the reader begins to energize the IC in the tag. Once the IC is energized, it goes through an initialization process and begins to broadcast its identity.
So it seems like the cards use induction to get just enough juice from the radio waves to power their internal circuitry. No battery needed.
Well, this is news to me. We pay 1.5% commission to Amex. In fact, of the major cards, they are the lowest commission rate, with Visa/MC charging 2.5%. Restaurants can pay upwards of 4.5% but that's as high as it gets.
Mods, please, downgrade the parent to over-rated. The AC has no idea what he is talking about. None.
Ryosen
One man's "Troll, +1" is another man's "Insightful, +1".
Offhand, I can think of two big ways to screw up the implentation:
Replay attacks - if the challenge is consistent through multiple authentication sessions, an attacker can reuse a hash response from a previous session. The solution is simple; better psuedo-randomness (using the date/time is a pretty poor idea, since an attacker can simply challenge the card with a date in the future and retrieve the needed response).
Poor hashing - if the hash used on the response is reversible, the password is right there for the taking. Solution, use something known to be strong, like blowfish or MD5.
Assuming the makers aren't stupid, they have a cryptographically secure system on-hand. You make an assumption based on a few out-of-context or unrelated cases that all security is useless. This is silly; while I don't have a lot of faith in secure systems as a whole, the flaw is rarely in the cryptography backing them, if it is implemented correctly. The reason for this is obvious; cryptography, and computing complexity, are easily-understood enough that developing mathematical models for security is easy. For example, we know--or rather, we believe very fervently, but cannot prove--that factoring large numbers is very, very difficult. Therefore, we trust RSA when implemented properly. Similarly, we know--or at least believe very strongly--that certain algorithms are very, very difficult to reverse. Therefore, we trust that if a bad guy gets our password file, he can only try to find our passwords via brute-force.
The difficulty of sniffing and cracking the protocol used is probably much greater than that of simply getting a waiter at a restaurant to swipe the cards of customers through a skimmer (traditional cards, that is). And security is really not about absolute security; it's simply about making sure that defeating is is more trouble than it's worth (I believe Bruce Schnieder said this, but I could be mistaken).
A 16 digit number is nothing to memorize, and the expiry date can be pretty easy as well. There's lots of people out there (more so in the mathematics/physics field) that can just look at a number, and a few moments later, be able to write it down.
So really, what's to prevent someone who works at a restaurant who takes your CC and memorizes the number, let alone write it down?
Af far as security for internet purchases is made, there's no real change.
Actually, the liability is usually $50 MAX *if* the card is stolen, and then, only before you report it.
If it's just fraudulent use, but your card wasn't stolen, you are not liable for a penny.
Further, this $50 liability is somewhat misleading, as the credit card company cannot charge you unless they can prove that you authorized the transaction....
If there is no signature, and no evidence that you yourself received the goods... (say they had no signature because it was an internet purchase, but the shipping address was your house..... thats' good evidence that you authorized it)
they can't charge you a dime.
If your agreement says something other than that, you need to shop around.
The poster is absolutely right. A close friend of mine works for American Express and is currently working on the contactless credit cards for Amex. He did a demo for me showing me how some of the software he wrote works with the card and the reader. I was really impressed at first, than I asked him what kind of cryptography they were using. He told me that it wasn't encrypted at all. I then asked him if it would be possible to steal the credit card information remotely using some type of radio snooping device. He told me he wasn't allowed to answer that question.
After talking to him more about the security (and he's very smart when it comes to cryptography and security) I came to find out that there were plans for adding security but it would cost to much.
I think some of the things my friend is working on are very cool but I for one will stay FAR away from contactless credit cards until they actually start using cryptography and are more than a glorified RFID tag.
Asking an RFID tag to encrypt something is like asking a new born baby to do calculus. You can't ask a device which has no battery of its own to compute something.
What does having a battery have to do with it? They're powered by the reader.
Both contact and contactless smart cards (which are not the same as RFIDs, although the difference is one of complexity rather than technology) do have the capability to perform cryptographic operations, both symmetric and asymmetric, and with sufficiently large keys to be secure.
If you'd like to know what these devices can really do, rather than guessing, take a look at the specifications for this one. Dual interface (contact or RF usage), on-card fingerprint matcher, 2048-bit RSA, 168-bit 3DES, SHA-1 and MD-5 secure hashes, hardware random number generator, on-board Java VM for executing user programs, six different comm protocols supported, with comm speeds ranging from 9600bps to 424kbps. It performs a 1024-bit RSA public key operation in 18ms, a private key operation in 163ms and 168-bit DES operations in nanoseconds.
Oh, but it doesn't have a battery.
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