THz Bistatic Backscatter Side-Channel Sensing at a Distance
THz Bistatic Backscatter Side-Channel Sensing at a Distance
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DOI：
10.1109/tap.2021.3111165
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发表时间：
2022-02
影响因子：
5.7
通讯作者：
S. Adibelli;P. Juyal;Milos Prvulović;A. Zajić
中科院分区：
文献类型：
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作者：
S. Adibelli;P. Juyal;Milos Prvulović;A. Zajić
本文介绍了传感和检测的背散射太赫兹（THz）的侧通道无意中创建的现场可编程门阵列（FPGA）的活动，使用双基地安排。首先，由于FPGA内部的开关活动，单个频率被调制到THz载波上，并且该调制频率在一定距离处被接收。研究了极化和接收距离对后向散射信号的影响，发现在发射机和接收机之间故意引入极化失配可以使信噪比提高10 dB以上。这使得信号可以在大于45 cm的距离处接收，SNR高于54 dB，使得在几米远的地方检测是可行的。通过使用近场聚焦器，在FPGA板的表面上以0.5 mm的分辨率测量侧信道信号的特性。接下来，通过将FPGA分成四个不同的模块，创建并检测四个不同频率的反向散射信号。比较频率的相对强度，并分析关于源自不同模块的这些信号的物理位置和强度的结论。发现将反向散射系统聚焦在FPGA上的某些位置上可以优先接收来自一个模块的信号，同时滤除其他模块。这有助于隔离FPGA中各个模块产生的信号，并显著提高边信道检测技术的有效性。
This article presents the sensing and detection of backscattered terahertz (THz) side channels unintentionally created by field-programmable gate array (FPGA) activity using a bistatic arrangement. At first, a single frequency is modulated onto a THz carrier due to the switching activity inside the FPGA and this modulated frequency is received at a distance. The effects of polarization and the receiver distance on the backscattered signal are studied and it is found that deliberately introducing a polarization mismatch between the transmitter and the receiver can improve the signal-to-noise ratio (SNR) by more than 10 dB. This allows the signal to be received at distances greater than 45 cm with SNR above 54 dB, making detection feasible at several meters away. Through the use of a near-field focuser, the properties of the side-channel signal are measured over the surface of the FPGA board with a resolution of 0.5 mm. Next, a backscatter signal at four distinct frequencies is created and detected through splitting the FPGA into four distinct modules. The relative strength of the frequencies is compared, and conclusions about the physical location and the strength of these signals originating from distinct modules are analyzed. It is found that focusing the backscatter system on certain locations on the FPGA can preferentially receive the signal from one module while filtering out the other modules. This helps isolating the signals created by various modules in an FPGA and significantly improving the effectiveness of side-channel detection techniques.