Researchers in Amsterdam say they have built a device that prevents radio frequency identification tags from being read. The project supervisor, Prof. Andrew Tanenbaum of the Vrije Universiteit Amsterdam, said the goal was to protect people from a technology that is gaining wide acceptance but threatens to compromise consumer privacy. The PDA-sized device, dubbed 'RFID Guardian', beeps when a nearby RFID scanner tries to read a chip the user is carrying, for instance in his or her clothing.

According to Tanenbaum, industry has no compunctions about invading personal privacy. For instance, he said that European banks plan to put RFID tags in large-denomination banknotes. That means a robber could walk down the street with a scanner to find out how much money you are carrying and see who would make the best target.

The RFID Guardian uses a 550-MHz XScale 32-bit processor with 64 MB of RAM. The protocol stack was written in C and runs under eCos, an open-source operating system. The project team plans to refine the software and hopes to commercialise the device.

Other companies are also developing similar products. RSA Security Inc., which protects online identities and digital assets, has created an RFID blocker that is intended to prevent RFID readers from scanning personal or private tags. According to an industry watcher, the challenge for RSA was to define which tags were private and who could access them.

An industry analyst who follows RFID issues in the retail industry said these types of devices point to a need for consumer privacy, but he doubted they would find mainstream acceptance.