Experimental Validation of Localization Method for Finding Magnetic Sources on IOT Devices

Recently, we proposed a method for accurately locating instruction-dependent magnetic field sources on printed circuit boards (PCBs). This method first excites the device's processor by executing an alternating pair of two instructions at a specific frequency. Using the measurements of the magnetic field taken around the edges of the PCB and an algorithm based on simplex optimization, the locations of the sources are evaluated. In this paper, we present extensive experimental verification of this method on two devices, a field-programmable gate array (FPGA) development board and an Internet of Things (IoT) device. The results illustrate that sources of instruction-dependent emanations are confined to a small area near the processor and that the positions of these sources are dependent on the specific instructions being executed.