Power-Aware Adaptive Encryption

Recently, there has been a significant increase in number of resource-constrained devices, which are typically battery-powered. Encryption schemes are employed to protect privacy of exchanged data. In such devices, balancing data security and devices resources is a critical design challenge. For resource constrained devices, energy is the most crucial resource. The research motivation is to adapt cipher energy based to predefined power levels using a single cipher with multiple implementation options.In this paper we propose a scheme to adjust power and energy consumption of single lightweight cipher based on current device power level. The scheme adjusts cipher energy by varying design options and operation complexity of the cipher. This includes varying number of implemented rounds in hardware, key scheduling and number of algorithm iterations. While altering number of algorithm iteration reduces security, it is better than inhibiting encryption or shutting down the device. Our proposed scheme allows adjustable encryption for low power level. Results from Field-programmable gate array (FPGA) implementations show energy savings of 35%-39% compared with implementations of existing designs.