Evaluating Compromising Emanations in Touchscreens

Abstract: In a short time touchscreens has become one of the most used methods for input to smartphones and other machines such as cash registers, card terminals and ATMs. While the technology change was quick it introduces the possibility of new security holes. Compromising emanations is a possible security hole in almost all electronic equipment. These emanations can be used in a side-channel attack if they leak information that compromise the security of the device. This thesis studies a single-board computer (SBC) with a touchscreen and a smartphone in order to evaluate if any usable information leaks regarding what is done on the touchscreen i.e. where on the screen a user touches. It is shown that the location of a touch can be read out from information leaking through the power cable and wirelessly from the single-board computer. It is also shown that basic information can be read out wirelessly from the smartphone but further testing is required to evaluate the possibility to extract usable information from the device.