A Low-Energy Security Algorithm for Exchanging Information in Wireless Sensor Networks

Because wireless sensor networks usually operate on unattended mode in hostile environments, the sensitive data should be protected using some sort of cryptography. Symmetric key scheme is more appropriate cryptography for wireless sensor networks due to its low energy consumption and simple hardware requirements, but most of them cannot provide sufficient security level (e.g. integrity, confidentiality, and authentication) as public key approach does. In this work, we propose a new security scheme that overcomes the limitations presented in both publicand symmetric-key protocols. The scheme relies on using one-way hash function to implement the data authenticity between nodes in the network, and a mix of symmetric and public key cryptography functions using the pre-distributed keys to implement the data confidentiality service. The symmetric key function is used to guarantee secure communications between in-network nodes while the public key function is used to guarantee a secure data delivery between the source node and the sink node. The proposed scheme is most suitable for wireless sensor networks that incorporate datacentric routing protocols. We have calculated the computational and communication overheads in terms of energy consumption in the new scheme using Directed Diffusion protocol [4]. The results have shown that the proposed scheme is scalable and an strong competitors to pure symmetric key schemes, yet, it maintains all security levels provided by public key schemes.