Design and Implementation of a Configurable Encryption System for Power-Constrained Devices

In this work, we present a configurable encryption system based on the Encryption by Synchronization in a Cellular Automata (ESCA) system, which is a symmetric key algorithm based on the synchronization phenomenon of Cellular Automata with rule-90. With the aim of producing a flexible system to trade-off power consumption and security level, we implemented a pseudo-random number generator (PRNG) that can be configured with three different key sizes. This variable-length PRNG, together with the capability of bypassing specific modules in the rest of the system, allow us to operate under a wide range of applications. In particular, it would enable online adjustments in IoT and power-constrained devices to finetune them between a low-power consumption and a maximum-security level. The system can be implemented with 5956 gates, and it is designed to provide in a 0.5 mu m CMOS process a throughput of 50 Mbps @ 37 mW, at the maximum-security level, and an energy consumption of less than 7 mW @ 30 Mbps at the lowest security level, while still providing a satisfactory perceptual security metric.