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鈥檚 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.
鈥淭his is a very real problem,鈥� 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.
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Taysom says that incorporating ultrathin switches into RFID-enabled devices 鈥� such as door-entry smartcards, travel passes and passports 鈥� is the answer, making it possible to turn them on and off at will. 鈥淚t lets the holder of the passport decide the very brief moment when it can be read,鈥� he explains.
鈥淚t lets the passport holder decide the very brief moment it can be read鈥�
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 鈥渙n鈥� 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鈥檚 switch, however, has no obvious moving parts. 鈥淭he 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,鈥� 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鈥檚 conductivity. This results in the flow, or 鈥渢unnelling鈥�, of electrons between the metal nanoparticles, which completes a circuit. By varying the number and size of the particles, the material鈥檚 properties can be tuned to switch on under the different pressures demanded by various applications.
鈥淭he change in state occurs locally, where the force is applied,鈥� says Taysom, which means accidental switch-on can be avoided: any flexing of a whole smart card 鈥� when you sit on it, say 鈥� will be distributed and not sufficient to activate the RFID.
So far Peratech has made switches 30 micrometres thick 鈥� thin enough to be placed under the laminated layer used in passports and smartcards.
鈥淭his is a good idea,鈥� says Ross Anderson, a computer security expert at the University of Cambridge. 鈥淎 better RFID switch material could have many uses.鈥� Nevertheless, he thinks Peratech is 鈥渘uts鈥� if it hopes to make a fortune from passports: 鈥淭hose designs were all settled years ago,鈥� he says. Some 45 countries are already rolling out passports incorporating RFID technology.
鈥淲here QTC might make Peratech some money though,鈥� Anderson predicts, 鈥渋s in the next generation of miniature input devices, such as switches on credit-card-sized security tokens.鈥� Such devices generate pseudo-random numbers or secure login codes on a small LCD 鈥� but they waste power because their displays, too, are always on.
Computer Viruses 鈥� Learn more about the threats to your PC in our comprehensive .
