Research On Key Management Protocol In Heterogeneous Sensor Networks

Key management in heterogeneous sensor networks(HSNs)is one of the hot spot that also concerns sensor networks security.As the growth of applications of wireless sensor networks(WSNs),the existing WSNs have expanded from the initial homogeneous network to heterogeneous network today,so it is more difficult and more challenging that the research on key management protocol of WSNs should fully consider the objective existence of heterogeneity in WSNs and be combined with the limited resources of the sensor nodes to design the practical,efficient and secure key management protocol which adapt to a certain network environment and application scenario.The main focuses of key management in wireless sensor networks are key pre-distribution scheme based on symmetry encryption system and authenticated key agreement protocol based on asymmetric encryption system.Existing key management protocols have pertinence that could improve performance or be suitable for a certain application environment,which do not take into account the global protocol performance to obtain the optimal strategy.This paper was closely associated with heterogeneity of WSNs.With combinatorial design,elliptic curve and variational inequality,the paper did in-depth researches in key pre distribution,key agreement,cross-layer design and protocol performance optimization.The main work of the paper is summarized as follows:(1)Most of key pre-distribution scheme based on combinatorial design are difficult to realize in the large-scale network environment and are in the absence of network topology,which are suitable for homogenous WSNs,not for heterogeneous WSN.In this paper,we presented a definition of combinatorial design,termed “w-balanced incomplete block design(w-BIBD)”,and then described a 2-D construction of w-BIBD which is mapped to KPD in WSNs.Our approach is of simple construction which provides a strong key connectivity and a poor network resilience.To improve the network resilience of 2_D w-BIBD,we proposed a key pre-distribution scheme based on 3-D EX-μ-BIBD which was a construction of w-BIBD from 2-D space to 3-D space.EX-w-BIBD KDP scheme improves network scalability and resilience while have better key connectivity.Theoretical analyses and comparison with the related schemes show that key pre-distribution scheme based on Ex-w-BIBD provides high network resilience and better key scalability,while it achieves a trade-off between network resilience and network scalability.(2)In order to tradeoff node load and prolong effective life time of WSNs,this paper designed a cross-layer key management scheme in heterogeneous WSNs based on energy balance.The scheme took residual energy of node as the main measure way,created session-key between nodes that were in the same route,and designed authenticated key agreement protocol based ECC.Theoretical analysis and experimental results show that the scheme ensures energy equilibrium as well as network security and saves sensor node storage,meanwhile computation complexity and power consumption are limited in the range of sensor node performance.(3)This paper presented an equilibrium model which could find the optimal distribution strategy to maximize performance of key predistribution protocols in terms of cost,resilience,connectivity and lifetime.As an essential attribute of wireless sensor networks,heterogeneity and its impacts on random key predistribution protocols were first discussed.Using supernetworks theory,the optimal node deployment model was proposed and illustrated.In order to find the equilibrium performance of our model,all optimal performance functions were changed into variational inequalities so that this optimization problem could be solved.A small scale example was presented to illustrate the applicability of our model.