You might want to look at the work RSA Labs is doing on 'blocker tags'. These are special tags which leverage the mechanism used to disambiguate the presence of multiple tags to make it look as if you are carrying 2^n (n usually 128) different tags at once. They propose a protocol to make them only block tags for items which have undergone sale to their final owner, but the idea could be applied to all tags. http://www.rsasecurity.com/rsalabs/rfid/index.asp Peter Trei Full Disclosure: I work for RSA

-----Original Message----- From: owner-cypherpunks@minder.net [mailto:owner-cypherpunks@minder.net]On Behalf Of Major Variola (ret) Sent: Wednesday, May 12, 2004 1:48 PM To: cypherpunks@al-qaeda.net Subject: We're jamming, we're jamming, we hope you like jammin too

At 03:09 PM 5/11/04 +0200, Eugen Leitl wrote:

...

The second covers a "hacking the system" concept. I'd considered something similar myself, though different in approach. Rather than finding RFID chips and "redistributing" them, why not create programmable RFID broadcasters which could spoof other chips, and distribute these. The idea being to pollute any RFID detectors with a vast spew of superfluous data.

RFID jamming should be very easy and a quite amusing DoS attack on commercial targets. Easy because its not frequency hopping, low power, and relatively low frequency. Particularly cute would be transmitting sex-toy codes intermittently.

ASK any Elmer you happen to see, what's the best jamming, RFID..

(With apologies to the tuna industry and those too young to know the jingle. Or to know the RF double meanings.)