Increasing design complexity and reduced time-to-market have motivated manufacturers to outsource some parts of the System-on-Chip (SoC) design flow to third-party vendors. This provides an opportunity for attackers to introduce hardware Trojans by constructing stealthy triggers consisting of rare events (e.g., rare signals, states, and transitions). There are promising test generation-based hardware Trojan detection techniques that rely on the activation of rare events. In this paper, we investigate rareness reduction as a design-for-trust solution to make it harder for an adversary to hide Trojans (easier for Trojan detection). Specifically, we analyze different avenues to reduce the potential rare trigger cases, including design diversity and area optimization. While there is a good understanding of the relationship between area, power, energy, and performance, this research provides a better insight into the dependency between area and security. Our experimental evaluation demonstrates that area reduction leads to a reduction in rareness. It also reveals that reducing rareness leads to faster Trojan detection as well as improved coverage by Trojan detection methods.

翻译：日益增长的设计复杂性和缩短的市场投放时间促使制造商将系统级芯片（SoC）设计流程的某些部分外包给第三方供应商。这为攻击者提供了通过构造由稀有事件（如稀有信号、状态和转换）组成的隐蔽触发器植入硬件木马的机会。目前存在有前景的基于测试生成的硬件木马检测技术，这些技术依赖于稀有事件的激活。在本文中，我们研究将稀有度缩减作为一种可信设计解决方案，以使攻击者更难隐藏木马（从而更易于木马检测）。具体而言，我们分析了减少潜在稀有触发器案例的不同途径，包括设计多样性和面积优化。尽管人们对面积、功耗、能量和性能之间的关系已有较好理解，但本研究为面积与安全性之间的依赖关系提供了更深入的见解。我们的实验评估表明，面积缩减会导致稀有度降低。此外，研究还揭示，稀有度降低可加速木马检测，并提升木马检测方法的覆盖率。