A Technical RFID Primer

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Posted by Hemos on Tuesday October 26, 2004 @02:35AM from the learn-more-about-it dept.

gManZboy writes "Roy Want, principal engineer at Intel Research, has a pretty meaty technical overview of RFID up at Queue. If you ever wondered how these little things actually work it's worth a read. For instance, I was intrigued to find out how the tags (which are generally battery-free) can absorb enough energy from RFID readers to then power up and transmit their own signal back to the reader."

5 of 131 comments (clear)

I think the public needs to know... by OccidentalSlashy · 2004-10-26 02:37 · Score: 5, Interesting

Are they biodegradable?

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vicious, untreated political sewage...niche entertainment for the spiritually unattractive...worshipless pap
RFID isn't a problem-free technology for retailers by hrbrmstr · 2004-10-26 02:45 · Score: 5, Informative

A little over a week ago, Yahoo! posted a story from TechWeb about IBM's experiences with Wal-Mart in their RFID deployment.
During the deployment, IBM consultants have encountered interference from handheld devices such as walkie-talkies, forklifts, and other devices typically found in distribution facilities. And nearby cell-phone towers, which transmit at the high end of the frequency band, sometimes leak unwanted radio waves into the RFID readers. Bug zappers in the grocery sections of the pilot stores also caused interference. "When you have a bug that hits the zapper, the RF power generated by the interaction with the bug produces noise in the coax cables," says Douglas Martin, executive consultant at IBM Global Services.
Regardless of how much a retailer's internal facility might disrupt their ability to monitor me, I still plan on getting one of RSA's RFID jammers when they're out.

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Mind the gap...
Old Tech hinted of this. by Technician · 2004-10-26 03:04 · Score: 5, Interesting

From the article,

In fact, various forms of crude RFID have been used since World War II.

What I think he is refering to but failing to mention by name is the aircraft friend or foe reflector. A tuned cavity was placed on an air craft that would reflect a radar signal many times inside the cavity then emit it back. This delay produced a second reflection to a radar scan. If the shadow image of the plane was on the display, it was a Friend. If it was absent, it was a Foe. It was known as a FOF transponder. (Friend Or Foe)

It has been upgraded to return the plane identification.

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The truth shall set you free!
Re:RFID isn't a problem-free technology for retail by HarveyBirdman · 2004-10-26 03:10 · Score: 5, Insightful

Great linked article. Full of FUD and paranoia. Very entertaining.
Ooo! A store can track my purchases up to 10 feet beyond their door! Wow! I better call Secret Squirrel for some countermeasure tips!
And of course it had the old idea of an ubergovernment plan of having sensors in every toilet seat and lamp post so that they can track how often I change my underwear.
Honestly, people... The X-Files is over, and our government can't keep Chechnyan rebels from crossing in from Mexico. They can't even prevent the vast waste and fraud perpetrated by the uneducated masses against the various money giveaway programs.
So they're suddenly get their act together and implement a shiny, sparkly supersensor array in order to track which communist manifesto you bought this week down at the Chairman Meow Bookshop/Animal Companion Emporium?
Regardless of how much a retailer's internal facility might disrupt their ability to monitor me, I still plan on getting one of RSA's RFID jammers when they're out.
Huh. Interesting. Do any descendants of P. T. Barnum work at RSA? I think you'd be better served by an orgone energy accumulator.

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--- Ban humanity.
Lukas Grunwald's Blackhat pres. + Linux tools! by phreakmonkey · 2004-10-26 03:44 · Score: 5, Informative

Lukas Grunwald did an excellent presentation at BlackHat USA 2004 about this very subject.
The most interesting thing that I learned was that most all RFID tags have a 128 byte "user data" buffer than can be read or written by ANY RFID gate. (Ie: you can put an RFID interface on your laptop and query the tags and change the "user data" portion on them.)
Obviously, this means that any application that is sensitive to tampering should only use the hard-coded serial numbers, not the "user data" area... but history has told us how well people stick to "common sense" security practices in their implementations.
His paper and the Linux tool that allows you to query and change the data are located here: http://www.blackhat.com/html/bh-media-archives/bh- archives-2004.html (scroll down to Lukas Grunwald under "Layer 0".