Measurement and analysis of the compromising electromagnetic emanations from USB keyboard

The keyboard of a computer is often used to transmit sensitive data such as passwords. Because keyboards is electronic devices, it is forced to emit an electromagnetic wave, in the process of transmitting data. These compromising electromagnetic emanations disclose sensitive information, such as input keys on the keyboard [1]. In this paper, leaked electromagnetic radiation from the cable of the USB keyboard are measured by using a field probe. And recovery of the data was performed through it. Two kinds of keyboards were analyzed by signal processing algorithm. In conclusion, it is determined that the recovery of key information from electromagnetic emanations was possible for a total of 36 key (A to Z, 1 to zero).