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We propose a method to include security and reliability to the messages sent over the CAN bus. Our approach adheres to CAN standard ISO 11898-1. A reliable PUF response is used in key generation to create a unique shared AES-256 key between each ECU, allowing for all message paths to be encrypted. In addition, an HMAC system with a counter is implemented to help protect against replay attacks and message tampering within the network. 

The last few decades have seen a large proliferation in the prevalence of cyber-physical systems. This has been especially highlighted by the explosive growth in the number of Internet of Things (IoT) devices. Unfortunately, the increasing prevalence of these devices has begun to draw the attention of malicious entities which exploit them for their own gain. What makes these devices especially attractive is the various resource constraints present in these devices that make it difficult to add standard security features. Therefore, one intriguing research direction is creating security solutions out of already present components such as sensors. Physically Unclonable Functions (PUFs) are one potential solution that use intrinsic variations of the device manufacturing process for provisioning security. In this work, we propose a novel weak PUF design using thermistor temperature sensors. Our design uses the differences in resistance variation between thermistors in response to temperature change. To generate a PUF that is reliable across a range of temperatures, we use a response-generation algorithm that helps mitigate the effects of temperature variation on the thermistors. We tested the performance of our proposed design across a range of environmental operating conditions. From this we were able to evaluate the reliability of the proposed PUF with respect to variations in temperature and humidity. We also evaluated the PUF’s uniqueness using Monte Carlo simulations. 

Internet of Things (IoT) devices are mostly small and operate wirelessly on limited battery supply, and therefore have stringent constraints on power consumption and hardware resources. Therefore, energy-efficient (low energy) design is paramount for the successful deployment of resource constrained IoT devices. Further, Physical Unclonable Functions (PUFs) have evolved as a popular hardware security primitive for low cost, mass produced IoT devices with very constrained resources. Energy harvesting technologies utilizing solar cells are being used in ultra-low power IoT devices to satisfy the energy requirement. In this paper, we utilize the intrinsic variations in solar cells to design a novel solar cell based PUF. As a proof of concept, we have used the Tiva TM4C123GH6PM microcontroller to build our solar cell based PUF. From our experiments, we found that the proposed solar cell based PUF has the uniformity value of 49.21% which is close to the ideal value of 50%. Further, the proposed solar cell based PUF has worst case reliabilities of 92.97% and 90.62% with variations in temperature and light intensity, respectively.