A collusion-resistant dynamic key management scheme for WSNs

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. Copyright © 2017 John Wiley & Sons, Ltd.