IMAGE: DIFRWear

Pocket Protector: A metal mesh maintains your privacy.

The adage “Just because you’re paranoid doesn’t mean they’re not out to get you” seems to be the motivating idea behind the line of wallets and passport ­holders from DIFRWear, in New York City. Although they look like regular leather wallets and holders, each is actually designed to protect you from 21st-century criminals.

In all likelihood, these criminals don’t exist yet, but just as online identity theft went from zero to costing consumers and companies a fortune in just a few short years [see “A Touch of Money,” IEEE Spectrum, July], it’s a pretty safe bet that they will be around before too long. These crooks will target wireless RFID tags, which already are used by many businesses to operate key-card entry systems and which are being embedded into credit and ID cards more and more frequently. The U.S. Department of State, meanwhile, is also currently testing RFID-enabled passports.

You can expect this new breed of criminal to carry RFID scanners to try to read the information stored on any tags in your possession—without even having to brush up against you. Although the normal range of an RFID scanner is a few centimeters, cheap electronics are all that is required to build a range extender capable of communicating with tags within a radius of several meters. Even when data on an RFID tag is protected by encryption, merely being able to detect a tag could put its bearer at risk. As futurist Bruce Sterling and others have noted, being able to determine remotely, say, who has a U.S. ­passport and who doesn’t in a crowded marketplace abroad could serve to identify potential victims for pickpocketing—or worse.

DIFRWear’s products solve this 21st‑century problem by falling back on some 19th‑century physics: the Faraday cage. Faraday cages are already used in many electronics products to block stray electromagnetic fields from causing interference. They work by enclosing subsystems in a metal box: physics dictates that electromagnetic fields cannot penetrate the box.

Fortunately, Faraday cages don’t have to be all-enclosing. They can have gaps and holes. DIFRWear works by lining the billfold within a wallet with a flexible fine aluminum mesh. When the wallet is closed, the two halves of the mesh are close enough together to form a Faraday cage and frustrate any RFID scanners. When it comes time to, say, swipe your key card to get into a building, simply open the wallet and hold it up to the sensor.

And even setting aside the criminal scenarios sketched out above, the DIFRWear wallet can come in handy. For example, one of my office key cards tends to set off store antitheft detectors. By banishing this card inside the wallet’s shield, I’ve eliminated the problem entirely.

The wallets sell for US $15, the passport holders for $18. Both come in a variety of colors. They can be ordered from DIFRWear’s Web site at http://www.difrwear.com, with an additional $3 required for worldwide shipping.