A collusion‐resistant dynamic key management scheme for WSNs

Abstract

Key management is an important security service for protecting wireless sensor networks (WSNs). Among various existing schemes, exclusion basis system (EBS) is a practical solution that can be easily implemented to provide long-term and flexible protection for WSNs. The involved rekeying strategy in EBS can efficiently evict the compromised node and update the key system. However, the relatively small key pool leads to high correlation among the generated key rings. Consequently, it is almost impossible for EBS-based schemes to efficiently defend collusion attack with their rekeying mechanisms. In this paper, we first analyze the impact of collusion attack on WSNs, especially that in the case where the keys of the compromised nodes can form a connected graph. Then, we propose a novel key management scheme based on EBS. The proposed scheme is termed as t-EEBS because it can effectively resist the referred collusion attack formed by t(t > 1) nodes. Furthermore, we assume that the proposed scheme is implemented in hierarchical WSNs. In this case, two layers of t-EEBS administrative keys are used. The upper layer is implemented among the base station and all cluster leaders, while the lower layer involves a t-EEBS for each cluster. The results of performance evaluation show that the proposed scheme has better resistance to collusion attack than other schemes. Therefore, the proposed scheme can provide better security service for WSNs. INTRODUCTIONWireless sensor networks (WSNs) have been used in a wide range of applications, such as transportation [1], healthcare [2], military [3], and environmental monitoring [4]. However, because of the inherent openness of wireless communication and unattended operation, WSNs are prone to various attacks. Therefore, some security mechanisms were proposed for protecting WSNs. For example, [5] proposed a public key infrastructure-enabled security framework for ZigBee sensor network, while [6] proposed a scheme for secure information dissemination in industrial WSNs.Key management is implemented to manage cryptographic keys in the network. According to [7], a typical key management process includes the following functions: key analysis, key assignment, key generation, and key distribution (and redistribution). Moreover, different entities might be used during the implementation of key management, such as key server, base station, and sensor nodes. The performance of key management significantly affects the security and efficiency of the network.Many key management schemes have been proposed for WSNs [8]. Different from other ad hoc networks, where asymmetric keys can be used to achieve key management [9], most key management schemes for WSNs were implemented based on symmetric keys with respect to resources consumption.In [10], a random key pre-distribution scheme was proposed for WSNs. This scheme includes three phases: key pre-distribution, shared-key discovery, and path-key establishment. Prior knowledge is not necessary in this scheme. This scheme is energy efficient. Based on [1...