CAJ | 학술논문

计算机键盘有用信号电磁截获的传统方法是基于宽带接收机完成的，这种方法较复杂且需要较多的设备和空间。为使键盘截获技术向小型化和实用化过渡，提出了使用基于软件无线电的解码技术及基于存储示波器全频谱远场截获。首先，基于频谱对比的方法对有用信号的频段进行初判，然后对截获的全频域信号中包含有敏感信息的频段基于软件无线电的方法进行带通滤波和解调。最后，使用一种能够精确判别按键信息的解码方法，通过预先设计的程序来实现信息的截获。实验结果表明计算机键盘有用信号电磁截获实现实用化和小型化是有一定可行性的，并且能够得到比较精确的结果。
계산궤건반유용신호전자절획적전통방법시기우관대접수궤완성적，저충방법교복잡차수요교다적설비화공간。위사건반절획기술향소형화화실용화과도，제출료사용기우연건무선전적해마기술급기우존저시파기전빈보원장절획。수선，기우빈보대비적방법대유용신호적빈단진행초판，연후대절획적전빈역신호중포함유민감신식적빈단기우연건무선전적방법진행대통려파화해조。최후，사용일충능구정학판별안건신식적해마방법，통과예선설계적정서래실현신식적절획。실험결과표명계산궤건반유용신호전자절획실현실용화화소형화시유일정가행성적，병차능구득도비교정학적결과。
The general technique based on a wide-band receiver may be complicated and need more devices. To make this technique for miniaturization and practicability, a new decoding technique based on software defined radio and full-spectrum far-field interception based on storage oscilloscope is represented. In advance, an interesting frequency is discovered by spectral analyzers. A full spectrum signal acquired by storage oscilloscope is filtered and demodulated using software radio technology on our interesting frequency. This paper introduces an accurate method to completely recover the keystrokes, and then get the result using pre-design software. Experimental results show that the miniaturization and practicality of PS/2 keyboard electromagnetic interceptions are feasible, and the result is also precise.