Study on electromagnetic compromising emanations of computer keyboard and its protection
计算机键盘电磁信息泄漏及其防护研究

This paper studied the circuit structure characteristic of data and clock signal interface in the PS/2 keyboard's control module. On this basis, it used the method of equivalent circuit to research the electromagnetic compromising emanations and its information recovery mechanism, the effectiveness of which was test and verified by a later measurement experiment. Furthermore, it proposed two different ways of security protection, and designed a shielding protection method against compromising emanations of keyboard. It is demonstrated by the result of the experiment that electromagnetic emission of keyboard is suppressed effectively and good protection effect against keystroke recovery is reached.