On Thu, 31 Mar 2005, Major Variola (ret) wrote:

At 10:08 PM 3/31/05 +0200, Eugen Leitl wrote:

...

government plan to insert remotely readable chips in American passports, calling the chips [2]homing devices for high-tech muggers,

So the market for faraday-cages for your passport will grow to equilibrium. A cage will cost less than a buck in parts, easily affordable by the clueful. The damage to the clueless will quickly be the best advertising for the product. Since we have been wearing conductive mesh burkhas for some time, the only inconvenience will be for the terahertz voyeurs employed by the TSA.

Beware of one gotcha. Faraday cage will shield only the electrical component. Low-frequency tags (125 kHz, typically) are magnetically coupled. Experiments shown that such tag is readable, even if entirely wrapped in aluminum foil. Laying a tag on top of a feromagnetic surface (iron sheet) does not help (probably only diminishes the range, didn't do the exact measurements yet); the sheet has to be between the tag's coil and the reader coil to be effective. Putting the tag into an enclosure made of a feromagnetic material helps, though. Altoids can proved to be a pretty effective shielding.