Noise-Jamming Effect as a Countermeasure Against TEMPEST during High-Speed Signaling

With digital devices, critical information can be left unsecured due to unintentional emissions from high-speed serial interfaces, such as digital visual interface, high-definition multimedia interface, universal serial bus, and mobile high-definition link. This study presents an analysis of the effectiveness of jamming to offset unwanted information leakage by means of transient electromagnetic pulse emanation surveillance technology from differential signal lines. For a quantitative analysis, a simplified simulation methodology is used to determine the reconstruction rate of the original digital signal as a function of the signal-to-noise ratio of the detected signal for various noise power levels. In addition, the effect of more realistic partial band-noise jamming is studied. It is shown that a jamming signal with a bandwidth ranging from 350 MHz to 3 GHz and with a relatively low level of power can effectively suppress the recovery of information obtained through radio frequency information emanation. This study shows that the band-noise-jamming method using correlated noise with a wide bandwidth is also useful as a countermeasure when considered within the electromagnetic compatibility limitations.