Using Digital Sensors to Leverage Chips' Security

Abstract

One way for an attacker to break a system is to perturb it. Expected effects are countermeasure deactivation or data corruption to disclose sensitive information. The prevention of such actions relies on detection of abnormal operating conditions. Digital sensors can play this role. A digital sensor is built out of the very same standard cells as the user logic to be protected. This ensures the advantage that the sensor and the user logic are exposed to the same stress. Balancing True positives and False negatives is a tough question in field of sensors. This is a general issue, and the best way to mitigate this paradox is to thoroughly investigate their properties, through simulations and real experiments. This results in characterizations, which in turn allows for intuitions on how to handle sensing values. In this paper, we exhibit the complex relationships between propagation times in logic and environmental conditions. Those results reinforce the relevance of the digital sensor versus the adversarial manipulation of environmental conditions: fewer false alarms are raised even if temperature (resp. voltage) is extreme, provided the effect is balanced by voltage (resp. temperature). Owing to the complex relationship between propagation delays, temperature and voltage, this cannot happen with a set of independent temperature and voltage sensors.

(Adversarial) Electromagnetic Disturbance in the Industry

“…14, page 189], suggested inserting an artificial critical path that raises the alarm when violated (before the user logic gets faulty). Such digital sensors are refined by T. Anik et al [48], and M. Ebrahimabadi et al [49] to measure the amount of perturbation injected into the chip (an approach known as time to digital conversion (TDC)). The merit of TDC is that they can be implemented as register transfer level (RTL) with standard delay constraints (SDC), hence their great portability amongst various targets (FPGA or ASIC) and technology nodes.…”

Detecting Laser Fault Injection Attacks via Time-to-Digital Converter Sensors

“…A digital sensor can be realized via inserting artificial critical paths (as simple as delay chains) into the chip logic such that if the chip is operated in abnormal conditions, setup time violations occur in the first place on the sensor's intentionally long paths [7]. In practice, the propagation time is not really quantified, rather it is checked if the transition manages to propagate to the end of the delay chain at the considered frequency [7]. In this paper we use such a sensor for detecting laser-based FIAs.…”

Reducing Aging Impacts in Digital Sensors via Run-Time Calibration

“…Analog sensors have been used for a long time as transducers that quantify the ambient conditions of electronic devices. These sensors, however, suffer from various flaws that have received considerable attention in recent years [19,14]. On the other hand, digital sensors have appeared as highly qualified counterparts concurring such drawbacks.…”

“…Optimizedperformance and reduced-power demands resulted in shrinking the feature size and in turn enabled a single chip to include billions of transistors. Ensuring the reliability and security of such complex circuitries is of utmost importance [19,14].…”

“…Consequently, it is necessary to sense the operating conditions such as voltage and temperature for optimized performance as well as tracking (preventing in some cases) the anomalies, malfunction, and malicious attacks. In practice, embedded sensors are used to notify the users by raising alarms while chips are operating out of specification violating the PVT corners [19], thus enhancing the chips' reliability and security.…”