On Tue, 12 Feb 2008 12:57:26 -0800 (PST), Jerry
wrote:


They work very well for something so small. A couple of months ago, I
started setting off the theft prevention alarms in just about every
store that had them. Walmart, Target, Kohls, Mervyns - you name it, I
set off their alarm. Started to be annoying when I would be walking
out of the store with nothing, and the security people would be
looking at me like they were thinking whether to ask if I had anything
in my pockets.

Took me a while to figure out what was setting off the alarms. I had
bought a new leather checkbook cover recently. Hidden in bottom of one
of the credit card slots was an RFID tag, paper-thin, and about 1 inch
square. Took it out and no more dirty looks from the "loss prevention
specialists".

Jerry

Spoofing store anti theft systems is becoming entertainment. Walmart
was/still uses the white plastic strip theft prevention. It is a
simple device that tells when a strip of metal is magnetized inside
the plastic. At the cashier, the strip passes a degausser in the
counter. When you pass the largish loop detectors on the way out,
they alarm on magnetized strips.

The spoofing comes in when people save the strips from purchases they
made then walk into the store with a magnet in one pocket and strips
in the other. They remagetize the strips and attach them to store
patron's clothing or just shopping carts, then sit at the lunch
counter and monitor the doors and wait for the fun to begin.

Disabling the devices is also becoming hacker entertainment. Pocket
degaussers and a device to disable the fusible RFID tags - the ones
that are just coming into use. They take the guts from a disposable
camera flash (tons of those available) and mate it to a coil with an
SCR trigger circuit. Hold the coil against the tag and discharge the
cap and it is supposed to kill the RFID device.

They claim that the price is still too high on the tags to make them
universal - I sort of doubt it. The ones I've seen look like a tiny
blob of plastic with a larger loop antenna that appears to be printed
on to the paper tag. With some ICs in the 20 cent range in quantity
rfid should be dirt cheap in the quantities they anticipate using -
especially with Walmart pushing it.

Our google groper needs to do a little research of his own.

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