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Can a smart polymer protect your RFID secrets?(New Scientist Via Acquire Media NewsEdge) IN THE last couple of months, a clutch of computer security experts have demonstrated just how easily the information stored in electronic passports can be cloned or manipulated without the owner's knowledge. The underlying problem is that the radio-frequency identification (RFID) tags laminated inside them are always turned on. That is, they are always ready to squirt out the data they contain on receipt of a radio signal. So the tag can be read surreptitiously at any time by anyone who passes close enough with a compatible reader. "This is a very real problem," says Philip Taysom, chief executive of Peratech in Brompton-on-Swale, North Yorkshire, UK. But he believes that a novel material developed by his sensing-technology company could dramatically reduce the risk of data loss. Taysom says that incorporating ultrathin switches into RFID-enabled devices - such as door-entry smartcards, travel passes and passports - is the answer, making it possible to turn them on and off at will. "It lets the holder of the passport decide the very brief moment when it can be read," he explains. This may sound like an obvious move, but incorporating a reliable switch in a slimline RFID device has proven an elusive goal. Even thin mechanical switches turn out to be too thick, tend to get stuck in ATMs or reading devices, and can be accidentally knocked into the "on" position. Most switches use conducting elements that are separated by an air gap, and when the elements meet they close a circuit, activating the device. Peratech's switch, however, has no obvious moving parts. "The material is a polymer which, when loaded in a certain way, changes its electrical behaviour from that of a resistor to that of a conductor," says Taysom. Dubbed the quantum-tunnelling composite (QTC), the material is essentially a plastic variable resistor. When pressure is applied to a small button-sized area, the proximity of spiked metal nanoparticles distributed within it changes, altering the material's conductivity. This results in the flow, or "tunnelling", of electrons between the metal nanoparticles, which completes a circuit. By varying the number and size of the particles, the material's properties can be tuned to switch on under the different pressures demanded by various applications. "The change in state occurs locally, where the force is applied," says Taysom, which means accidental switch-on can be avoided: any flexing of a whole smart card - when you sit on it, say - will be distributed and not sufficient to activate the RFID. So far Peratech has made switches 30 micrometres thick - thin enough to be placed under the laminated layer used in passports and smartcards. "This is a good idea," says Ross Anderson, a computer security expert at the University of Cambridge. "A better RFID switch material could have many uses." Nevertheless, he thinks Peratech is "nuts" if it hopes to make a fortune from passports: "Those designs were all settled years ago," he says. Some 45 countries are already rolling out passports incorporating RFID technology. "Where QTC might make Peratech some money though," Anderson predicts, "is in the next generation of miniature input devices, such as switches on credit-card-sized security tokens." Such devices generate pseudo-random numbers or secure login codes on a small LCD - but they waste power because their displays, too, are always on. Copyright ? 2008 Reed Business Information - UK. All Rights Reserved. |