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The US CDC has recognized moist-heat as one of the most effective and accessible methods of decontaminating N95 masks for reuse in response to the persistent N95 mask shortages caused by the COVID-19 pandemic. However, it is challenging to reliably deploy this technique in healthcare settings due to a lack of smart technologies capable of ensuring proper decontamination conditions of hundreds of masks simultaneously. To tackle these challenges, we developed an open-source wireless sensor platform---VeriMask1 ---that facilitates per-mask verification of the moist-heat decontamination process. VeriMask is capable of monitoring hundreds of masks simultaneously in commercially available heating systems and provides a novel throughput-maximization functionality to help operators optimize the decontamination settings. We evaluate VeriMask in laboratory and real-scenario clinical settings and find that it effectively detects decontamination failures and operator errors in multiple settings and increases the mask decontamination throughput. Our easy-to-use, low-power, low-cost, scalable platform integrates with existing hospital protocols and equipment, and can be broadly deployed in under-resourced facilities to protect front-line healthcare workers by lowering their risk of infection from reused N95 masks. We also memorialize the design challenges, guidelines, and lessons learned from developing and deploying VeriMask during the COVID-19 Pandemic. Our hope is that by reflecting and reporting on this design experience, technologists and front-line health workers will be better prepared to collaborate for future pandemics, regarding mask decontamination, but also other forms of crisis tech. 

Temperature sensing and control systems are widely used in the closed-loop control of critical processes such as maintaining the thermal stability of patients, or in alarm systems for detecting temperature-related hazards. However, the security of these systems has yet to be completely explored, leaving potential attack surfaces that can be exploited to take control over critical systems. In this paper we investigate the reliability of temperature-based control systems from a security and safety perspective. We show how unexpected consequences and safety risks can be induced by physical-level attacks on analog temperature sensing components. For instance, we demonstrate that an adversary could remotely manipulate the temperature sensor measurements of an infant incubator to cause potential safety issues, without tampering with the victim system or triggering automatic temperature alarms. This attack exploits the unintended rectification effect that can be induced in operational and instrumentation amplifiers to control the sensor output, tricking the internal control loop of the victim system to heat up or cool down. Furthermore, we show how the exploit of this hardware-level vulnerability could affect different classes of analog sensors that share similar signal conditioning processes. Our experimental results indicate that conventional defenses commonly deployed in these systems are not sufficient to mitigate the threat, so we propose a prototype design of a low-cost anomaly detector for critical applications to ensure the integrity of temperature sensor signals.