London, October 22 : Swiss researchers have shown that computer criminals can misuse the electromagnetic signals produced by when buttons on a keyboard to eavesdrop on what a user types.
Martin Vuagnoux and Sylvain Pasini, doctoral students from the Security and Cryptography Laboratory at the Swiss Ecole Polytechnique Federale de Lausanne (EPFL), have been successful in analysing the signals produced by keystrokes to reproduce what a target typed.
The researchers have developed four attacks that work on a wide variety of computer keyboards, which also worked with keyboards embedded in laptops.
Their findings forced them to declare that keyboards were "not safe to transmit sensitive information".
During the study, the EPFL students tested 11 different keyboard models that connected to a computer either through a USB or through a PS/2 socket.
The team observed that all the keyboards tested by them were vulnerable to at least one of the four attacks they used.
According to them, one attack could even work over a distance of 20 metres.
The researchers revealed that they used a radio antenna in their study, which enabled them to "fully or partially recover keystrokes" by spotting the electromagnetic radiation emitted when keys were pressed.
"No doubt that our attacks can be significantly improved, since we used relatively unexpensive equipments," the BBC quoted them as saying in a web posting.
Though the details of the attacks are scant, the new study is expected to be reported in a peer-reviewed journal soon.