Aged but Fit: Long Lasting Security for Trusted Platforms

随着工艺技术的不断扩展，CMOS纳米技术中的时间依赖性可靠性退化（所谓的老化）变得越来越严重。老化会在一定时间内改变晶体管的规格，进而改变底层器件的时序和功耗。对于加密设备，老化不仅从可靠性的角度来看是至关重要的，而且还需要从安全的角度进行全面的考虑，因为与老化相关的降级可能会使对手通过侧通道分析和故障注入攻击或通过特洛伊木马插入来泄露敏感信息。尽管近年来与老化相关的可靠性降低已得到广泛解决，但老化对加密设备安全性的影响在很大程度上仍未得到探索。密码设备具有处理机密数据的广泛应用。由于这些应用的敏感性，因此完全需要解决这些设备关于老化的安全性。为缓解这一问题，本提案围绕以下主题展开：（i）通过设计规避主动和被动物理攻击的老化感知对策来利用加密设备的安全性，（ii）重新审视加密设备中关于老化效应的特洛伊木马检测方案，（iii）关于老化感知的PUF构造的新发展。现有技术的老化缓解方案可以通过延长设备的寿命和推迟对老化相关故障的观察来增强设备的可靠性，但是这些方案不能彻底解决密码设备的安全问题，因为即使是很小的老化引起的不平衡也会损害用来保护免受物理攻击的对策。因此，对手可能会恶意地加速老化，以挫败保护方案。另一方面，老化可能有利于加强特定的物理攻击或削弱某些特洛伊木马激活机制。作为一个例子，我们可以参考分析SCA攻击，其中比较不同设备的侧通道签名。该项目将通过制定认识老龄问题的解决方案来解决现有计划的不足。这项研究的结果将在FPGA结构和ASIC原型上进行评估。

With the aggressive scaling of process technology, time-dependent reliability degradations, so-called aging is becoming more severe in CMOS nanotechnologies. Aging changes the specifications of transistors during the time and in turn, the timing and power consumption of the underlying devices. For cryptographic devices, aging is not only crucial from the reliability point of view but also needs a thorough consideration from security perspective as aging-related degradations may benefit the adversaries in leaking sensitive information through side-channel analysis and fault-injection attacks or via Trojan insertion. Although aging-related reliability degradation has been extensively addressed in recent years, the impact of aging on the security of cryptographic devices has remained largely unexplored. Cryptographic devices have a broad range of applications dealing with confidentail data. Due to sensitivity of such applications, there is a thorough need to address the security of these devices with respect to aging. To alleviate this problem, this proposal is structured around the following topics: (i) leveraging the security of cryptographic devices via designing aging-aware countermeasures that circumvent active and passive physical attacks, (ii) revisiting Trojan detection schemes in cryptographic devices with respect to aging effects, (iii) novel developments with respect to aging-aware PUF constructions.Deploying the state-of-the-art aging mitigation schemes can enhance device reliability by prolonging its lifetime and postponing observation of aging-related malfunction, yet these schemes cannot thoroughly address security concerns of cryptographic devices, as even small aging-induced imbalances can compromise the countermeasures leveraged to protect against physical attacks. As a consequence, an adversary may maliciously accelerate aging to thwart the protection schemes. On the other hand, aging may be beneficail to harden particular physical attacks or to weaken certain Trojan activation mechanisms. As an example, we can refer to profiling SCA attacks, where side-channel signature of different devices are compared. This project will address the shortcoming of existing schemes by developing aging-aware solutions. The outcome of this research will be evaluated on FPGA fabrics and ASIC prototypes.