A New Key Predistribution Scheme for Multiphase Sensor Networks Using a New Deployment Model

Hindawi Publishing Corporation Journal of Sensors Volume 2014, Article ID 573913, 10 pages http://dx.doi.org/10.1155/2014/573913 Research Article A New Key Predistribution Scheme for Multiphase Sensor Networks Using a New Deployment Model Boqing Zhou,1,2 Jianxin Wang,2 Sujun Li,1,2 and Weiping Wang2 1 2 Hunan University of Humanities, Science and Technology, Loudi, Hunan 417000, China School of Information Science and Engineering, Central South University, Changsha, Hunan 410083, China Correspondence should be addressed to Jianxin Wang; Received 1 May 2014; Accepted 18 May 2014; Published 15 June 2014 Academic Editor: Athanasios V. Vasilakos Copyright © 2014 Boqing Zhou et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. During the lifecycle of sensor networks, making use of the existing key predistribution schemes using deployment knowledge for pairwise key establishment and authentication between nodes, a new challenge is elevated. Either the resilience against node capture attacks or the global connectivity will significantly decrease with time. In this paper, a new deployment model is developed for multiphase deployment sensor networks, and then a new key management scheme is further proposed. Compared with the existing schemes using deployment knowledge, our scheme has better performance in global connectivity, resilience against node capture attacks throughout their lifecycle. 1. Introduction Due to limited energy capacity of batteries and the possibility of node capture, the functional lifetime of sensor networks (SNs) generally is longer than the operational lifetime of single node. To keep networks working efficiently, multiple deployments of nodes are needed. In the paper, multiphase SNs (MSNs) are studied, in which new nodes are periodically redeployed with certain intervals, called multiphase, to replace the dead or compromised nodes. When SNs are deployed in a hostile environment, security becomes extremely important as they are vulnerable to different types of malicious attacks [1–4]. Hence, it is important to protect communications among sensor nodes to maintain message confidentiality and integrity. As one of the most fundamental security services, pairwise key establishment enables sensor nodes to communicate securely with each other using cryptographic techniques. Public-key operations (both software and hardware implementations), albeit computationally feasible [5, 6], consume energy approximately three orders of magnitude higher than symmetric key encryption [7]. Therefore, in the last few years, different key distribution schemes using symmetric key algorithms have been developed for SNs [8–26]. However, the security issue is still not solved for MSNs by using deployment knowledge. In the schemes [16, 17], a fraction of keys known by an attacker increases with the capture of nodes due to the repeated use of a fixed key pool. As a result, network security significantly declines with time. When a certain number of these nodes are captured, the adversary has enough keys to compromise a large number of links making the network ineffective. Addition of new nodes to the network with keys from the same key pool will not help because the keys in the new nodes are compromised. In [20], a multiphase key management scheme is proposed, in which a multiphase deployment model is used. However, it has the following shortcomings. (1) In a cell, only a few nodes which are not captured are working in a long time. (2) Nodes must know their location information. (3) The number of new nodes added to the network is fixed in every deployment, which will give rise to the number of nodes uncaptured in the network with time. Also, the key management scheme proposed based on the deployment model has the following shortcomings. (1) Nodes which reside in the same cell but are deployed in different phases cannot communicate with each other. As a result, the local connectivity is low. (2) The global connectivity will significantly decrease with time. 2 Journal of Sensors 1.1. Outline of Our Scheme. To sum up, the problem of authentication and pairwise key establishment between nodes is still not solved for MSNs. In this paper, the main focus is twofold. (1) A new multiphase deployment model is proposed for sensor networks. In the model, the deployment field is divided into hexagonal cells, each cell has a deployment point, and nodes which have the same point form a group. When the proportion of uncaptured nodes in a group is less than the threshold 𝜌0 , new nodes are needed to be added to the cell. (2) A new key management scheme is proposed based on the deployment model. In our scheme, network deployment includes 𝑛 phases. For a cell, a disjoint and association 𝑛 phases’ key pool is created, which is generated by two-dimension backward key chains [21]. Key pool of each phase is divided into 7 equal size subkey pools. And nodes deployed in the 𝑖th phase and deployed in a cell (𝑟, 𝑐) pick keys from the 𝑖th-phase key pool of the cell (𝑟, 𝑐) and key pools which are created by neighbors cells of the cell (𝑟, 𝑐). 1.2. Main Contributions. The main contributions of this paper are summarized as follows. (1) A multiphase deployment model is presented. The model has the following two main advantages: (1) the number of nodes which are not captured in a cell can be controlled by adjusting the parameter 𝜌0 ; (2) nodes do not need to know their location information. (2) A new method to construct key pools is proposed and a new key predistribution scheme is presented. The scheme can provide good performances in local connectivity, global connectivity, and resilience against node capture. 1.3. Organization. The remainder of the paper is organized as follows. The existing schemes are summarized in Section 2. The model of deployment is introduced in Section 3. Our approach is proposed in Section 4 and the analysis and simulation results are provided in Section 5. Conclusion and future work are given in Section 6. 2. Related Work To improve the performance of key establishment, Du et al. [16] and Yu and Guan (YG scheme) [17] developed a scheme using predeployment knowledge, respectively. In [16], the network area is divided into a grid and information on the associated matrices is stored in the sensors based on deployment knowledge. In [17], the network area is divided into hexagonal cells. Compared with [16], the scheme achieves a higher connectivity with a much lower memory requirement and a shorter transmission range. In the two schemes, all nodes choose their keys from the same key pool. An attacker can easily obtain a large number of keys by capturing a small fraction of nodes, which can make SNs ineffective. The addition of new nodes to the network with keys from the same key pool will not help because the keys (...truncated)