Dynamic Adjustment of the Chaos-Based Security in Real-Time Energy Harvesting Sensors

Wireless Sensor Networks (WSNs) are a growing field of research since they are used in many applications. Nevertheless, they are subject to many requirements such as real-time constraints, energy limitations, and security requirements for the communications. Energy Harvesting is a new paradigm in WSNs: sensor nodes are powered by energy harvested from the ambient, rather than by non-rechargeable batteries which permits a potentially perpetual operation. However, energy harvesting poses new challenges in the design of WSNs, in that energy availability fluctuates over the time. In this paper, we investigate the following fundamental question: how should the harvested energy be managed to guarantee data security in all circumstances? Our contributions in this paper are twofold: First, we propose the Deadline Mechanism to dynamically cope with energy shortage and guarantee the highest possible quality of protection by the use of different encryption algorithms. Second, we design a new chaos based cryptosystem suitable for WSNs. Indeed, the proposed encryption/decryption scheme is robust against all known attacks. Experiments show that it is at least 7 times faster than the AES algorithm and also, faster than many chaos based cryptosystems of the literature. Our objective is to identify low-complexity policies that achieve close-to-optimal performance, in terms of maximizing the average long-term importance of the reported data.