By Mary Catherine O'Connor

Apr. 1, 2007—As radio frequency identification tags wend their way into more consumer applications—from access cards to payment devices, library cards, passports and clothing—privacy advocates, politicians and, increasingly, consumers are crying "foul." But as concerns grow that RFID tags are susceptible to skimming—being read surreptitiously—or being used for surveillance, so do efforts to safeguard RFID tags in order to prevent data from falling into the wrong hands. Some of these efforts—such as encryption techniques that ensure tags can be read only by authenticated readers—are still in the preliminary research stage. But other technology tools are available today, as are some low-tech tag protectors (see box).

The security firm Privaris makes a device called plusID that uses a biometric lock to prevent someone from using your access card or reading your ID and cloning the data onto another device. To gain entry with plusID, you have to press your finger on the device's integrated fingerprint reader. A processor inside the device compares your fingerprint scan with one saved in its onboard memory. If it matches, it enables the tag inside to be read. PlusID, which is small enough to add to a keychain, works with most access control systems that operate in the 125 KHz or 13.56 MHz frequency range. It is being used by a number of companies and by military personnel at high-security facilities.

The plusID from Privaris, which is small enough to fit on a keychain, can prevent someone from using your access card.

Raytheon, a government defense, aviation and technology company, has recently unveiled a prototype of a device called the PAD (personal authentication device), which is very similar to plusID, except that it has a UHF EPC Gen 2-compliant tag. Raytheon is proposing that the PAD be issued to U.S. citizens as a biometrically verifiable identity card for various Department of Homeland Security initiatives.

RFIDsec, an RFID startup, has developed an RFID security system that consists of specially designed tags and interrogator software, which uses a 128-bit key to place the tags in an unreadable privacy mode. The company says it has built the technology into HF tags—commercially available in July—compliant with the ISO 15693 and ISO 14443 air-interface protocols. The RFIDsec tags could be embedded in access control, identification and payment cards, as well as in labels that libraries place inside books. "We are running live demonstrations [of the HF tag] already and running a pilot project with a large library," says Mikkel Winther, executive vice president at RFIDsec.

The company is looking for business partners to help fund its effort to develop the system for UHF Gen 2 tags and interrogators, which would provide an alternative to killing product tags at the point of purchase. In order to provide the privacy-mode service to consumers, companies would need to run the RFIDsec software on their reader networks. But RFIDsec imagines that one day consumers will carry their own RFID interrogators on which they could run the RFIDsec application to control the readability of tags in their possession.

The RFID Guardian, being developed by researchers at Vrije Universiteit (Free University) in Amsterdam, could allow consumers to do just that. The Guardian uses a set of digital keys to permit or restrict RFID tags from being read, just as firewalls permit or deny entry into a computer network. The device reads the RF communication from an interrogator and checks the signal for a digital signature, or key, signifying it is authorized. If the Guardian sees the key, it allows the tag to be read. If the interrogator is not using an authorized key, the Guardian emits a jamming signal, preventing the interrogator's signal from reaching the tag.