关键词: 电磁木马, 基于软件的瞬时电磁脉冲发射监测技术（Soft-TEMPEST）, 应用程序编程接口（API）周期挖掘, 傅里叶变换, 频谱分析

Abstract: Display electromagnetic trojan is a new type of trojans that steal information through the control of computer screen electromagnetic radiation. The mainstream protection idea is that software protections substitute hardware protections mechanism which is more mature, but high cost. However, the current soft protections mostly come from the perspective of theoretical methods, which results in a relative complex implementation. This paper proposes a mechanism of Soft-TEMPEST against monitor electromagnetic trojans and designs a method ADFA（APIs Detection and Frequency Analysis）. The ADFA detects monitor electromagnetic trojans by cyclical mining API function sequences with Fourier transform of screen pixel information and spectrum analysis. The test results show that the method can successfully detect many types of monitor electromagnetic trojans. What is more, it is simple and can be easily put into use.

Key words: electromagnetic trojan, Soft-Transient Electromagnetic Pulse Emanation Surveillance Technology（TEMPEST）, Application Programming Interface（API） cyclical mining, Fourier transform, spectrum analysis