The global semiconductor supply chain involves design and fabrication at various locations, which leads to multiple security vulnerabilities, e.g., Hardware Trojan (HT) insertion. Although most HTs target digital circuits, HTs can be inserted in analog circuits. Therefore, several techniques have been developed for HT insertions in analog circuits. Capacitance-based Analog Hardware Trojan (AHT) is one of the stealthiest HT that can bypass most existing HT detection techniques because it uses negligible charge accumulation in the capacitor to generate stealthy triggers. To address the charge sharing and accumulation issues, we propose a novel way to detect such capacitance-based AHT in this paper. Secondly, we critically analyzed existing AHTs to highlight their respective limitations. We proposed a stealthier capacitor-based AHT (fortified AHT) that can bypass our novel AHT detection technique by addressing these limitations. Finally, by critically analyzing the proposed fortified AHT and existing AHTs, we developed a robust two-phase framework (DeMiST) in which a synchronous system can mitigate the effects of capacitance-based stealthy AHTs by turning off the triggering capability of AHT. In the first phase, we demonstrate how the synchronous system can avoid the AHT during run-time by controlling the supply voltage of the intermediate combinational circuits. In the second phase, we proposed a supply voltage duty cycle-based validation technique to detect capacitance-based AHTs. Furthermore, DeMiST amplified the switching activity for charge accumulation to such a degree that it can be easily detectable using existing switching activity-based HT detection techniques.

翻译：全球半导体供应链涉及不同地点的设计与制造，从而引发多种安全漏洞，例如硬件木马（HT）的植入。尽管大多数HT针对数字电路，但HT也可植入模拟电路。因此，现有多种针对模拟电路HT植入的技术。电容型模拟硬件木马（AHT）是最隐秘的HT之一，它通过利用电容器中可忽略不计的电荷积累生成隐秘触发信号，从而能绕过大多数现有HT检测技术。为解决电荷共享与积累问题，本文提出一种新型方法来检测此类电容型AHT。其次，我们批判性地分析了现有AHT技术，以突出其各自的局限性。我们提出了一种更隐秘的电容型AHT（增强型AHT），通过克服这些局限性可绕过我们提出的新型AHT检测技术。最后，通过批判性分析所提出的增强型AHT与现有AHT，我们开发了一个稳健的两阶段框架（DeMiST），其中同步系统可通过关闭AHT的触发能力来缓解电容型隐秘AHT的影响。第一阶段，我们展示了同步系统如何通过控制中间组合电路的供电电压在运行时规避AHT。第二阶段，我们提出了一种基于供电电压占空比的验证技术来检测电容型AHT。此外，DeMiST将用于电荷积累的开关活动放大到可通过现有基于开关活动的HT检测技术轻松检测的程度。