Key Management Scheme For Hierarchical Wireless Sensor Networks

Wireless sensor networks (WSN) is formed by a large number of low-cost, low powermicro-sensor nodes in self-organized way which are able to perform sensing, data processing andwireless communications. Owing to sensor nodes features and special application environment,wireless sensor networks faces many security challenges, and key management is the foundation andcore of some security mechanisms.This thesis describes the evaluation criterion of key management scheme and their classificationin wireless sensor networks. Then we discuss some typical distributed and hierarchical keymanagement schemes. Hierarchical wireless sensor networks can significantly prolong the networklifetime and increase the network connectivity, therefore this thesis pays more attentions to it, andputs forward two secure and efficient key management scheme inter-cluster key sharing.When sensor nodes which are more than that threshold value are compromised, security ofpolynomial pool-based key pre-distribution scheme is very poor. This thesis proposes a novel keypre-distribution scheme for hierarchical wireless sensor network aimed at improving this disadvantage.This scheme inherits the idea of using generating key by hash function which is appeared in theprobabilistic generating key pre-distribution scheme. And this scheme can reduce sensor nodesstorage cost and guarantee a high connectivity by adjusting relevant parameters. And furthermore, thisscheme has the threshold property, and provides more sufficient resilience against node capture attackthan the original scheme in the same connectivity.Based on threshold key sharing model in wireless sensor networks, this thesis also presents a keymanagement for hierarchical wireless sensor networks with group deployment of sensor nodes. Thisscheme employs Shamir’s secret sharing technique to re-construct sensor nodes’ keys in a deployedgroup. This thesis also proposes corresponding dynamic key management scheme to addressnode-addition, node-deletion and key-update issues. As is shown in theoretical analysis andexperiments, this scheme with high connectivity decreases the sensor nodes’ overheads and improvesnetwork security than the previous scheme. Comparing with threshold key sharing scheme, thisscheme greatly decreases storage, computation and communication overhead in the same security.