Building a Faraday Cage in Clothing to Shield RFID Tags

Filed in archive Privacy and Security on October 19, 2005

RFID tag privacy and security is an issue getting growing attention. As the use of RFID grows and touches consumers' lives, concern is also growing about whether tag data is secure or whether tags can be "forced to talk" and reveal private information.

A number of companies are working on or offer solutions to prevent tags from being scanned improperly or the tag data being "eavesdropped" or "skimmed" impermissably. Solutions range from tag encryption, to jamming devices, to kill switches, to tag blocking.

One time-honored, low-tech way to prevent tags from being eavesdroppedskimmed is the "Faraday cage." A Faraday Cage (described here, here and here) is a metal enclosure that prohibits radio frequency signals from passing through it.

Well, now, Mikey Sklar, a technology enthusiast from New York, has done a project on how to swap out the regular pockets on your pants and replace them with Faraday Cage pockets. (Just in case you were worried about that RFID-chipped passport in your pocket.)

His version of a Faraday Cage involves the use of shielding fabric with wire mesh embedded in it, available from Less EMF. The photo above accompanying this post shows a pair of pants with the pocket on the left made of the shielding fabric, and the regular pocket on the right. He's even made a movie of his Faraday Cage pocket project. You can find the movie, more photographs and a write-up on his website, Electric Clothing.

I emailed Mikey asking permission to reproduce the photograph, which he kindly gave, and here is what he told me:

"This January I am scheduled to give the same talk at NYC's dorkbot meeting. In additional to the slides on my RFID Pocket page I will be injecting select members of the audience with RFID tags into their hands.

You might wonder why I would go out of my way to put RF sheilds in my pants, and then injecting RFID tags into myself and others. My philosphy is that there is nothing we can do at this point to prevent RFID from becoming pervasive. Understanding RFID's weaknesses before it becomes completely mainstream can be of great value to all of us."

You know what all this means, don't you? The tinfoil hat -- that butt of countless Internet parodies and derision -- really does work after all.

P.S., In case you were expecting to read something highly technical about RFID tag privacy and security issues -- not the whimsical treatment of this post -- please read "RFID Security and Privacy: A Research Survey" (PDF) by Ari Juels of RSA Laboratories. It appears to be a particularly detailed and authoritative paper, and is very current having been written in September 2005.