Biblio

Data security is the main challenge in Internet of Things (IoT) applications. Security strength and the immunity to security attacks depend mainly on the available power budget. The power-security level trade-off is the main challenge for low power IoT applications, especially, energy limited IoT applications. In this paper, multiple encryption modes that provide different power consumption and security level values are hardware implemented. In other words, some modes provide high security levels at the expense of high power consumption and other modes provide low power consumption with low security level. Dynamic Partial Reconfiguration (DPR) is utilized to adaptively configure the hardware security module based on the available power budget. For example, for a given power constraint, the DPR controller configures the security module with the security mode that meets the available power constraint. ZC702 evaluation board is utilized to implement the proposed encryption modes using DPR. A Lightweight Authenticated Cipher (ACORN) is the most suitable encryption mode for low power IoT applications as it consumes the minimum power and area among the selected candidates at the expense of low throughput. The whole DPR system is tested with a maximum dynamic power dissipation of 10.08 mW. The suggested DPR system saves about 59.9% of the utilized LUTs compared to the individual implementation of the selected encryption modes.

Approximate Computing aims at trading off computational accuracy against improvements regarding performance, resource utilization and power consumption by making use of the capability of many applications to tolerate a certain loss of quality. A key issue is the dependency of the impact of approximation on the input data as well as user preferences and environmental conditions. In this context, we therefore investigate the concept of self-adaptive image processing that is able to autonomously adapt 2D-convolution filter operators of different accuracy degrees by means of partial reconfiguration on Field-Programmable-Gate-Arrays (FPGAs). Experimental evaluation shows that the dynamic system is able to better exploit a given error tolerance than any static approximation technique due to its responsiveness to changes in input data. Additionally, it provides a user control knob to select the desired output quality via the metric threshold at runtime.

Authentication and encryption within an embedded system environment using cameras, sensors, thermostats, autonomous vehicles, medical implants, RFID, etc. is becoming increasing important with ubiquitious wireless connectivity. Hardware-based authentication and encryption offer several advantages in these types of resource-constrained applications, including smaller footprints and lower energy consumption. Bitstring and key generation implemented with Physical Unclonable Functions or PUFs can further reduce resource utilization for authentication and encryption operations and reduce overall system cost by eliminating on-chip non-volatile-memory (NVM). In this paper, we propose a dynamic partial reconfiguration (DPR) strategy for implementing both authentication and encryption using a PUF for bitstring and key generation on FPGAs as a means of optimizing the utilization of the limited area resources. We show that the time and energy penalties associated with DPR are small in modern SoC-based architectures, such as the Xilinx Zynq SoC, and therefore, the overall approach is very attractive for emerging resource-constrained IoT applications.