Trust Model Of Wireless Sensor Networks Based On Hierarchical Trust Management

As microelectronics, wireless communications technology matures, wireless sensor networks technology are developing rapid. With the widely used of wireless sensor networks, its security threats are also increasing. Traditional security defense system which based on password just is able to withstand the external security threats. Network can not balance node energy consumption to become a bottleneck restricting the application of WSNs. Meanwhile, the selfish nodes in wireless sensor networks become its’own internal security threat. These problems are all need to be resolved by WSNs.In recent years, the trust model of WSNs became the research focus. It’s the complement of password-defense system. It is able to respond to most security threats for WSNs. The problem that the traditional trust model considers trust factors relatively homogeneous lead to the trust evaluation of the network nodes is not objective enough and comprehensive. Trust management takes a centralized or decentralized way and it is not flexible enough.On the basis of in-depth study about WSNs trust model on the domestic and international, this paper proposes a trust model based on hierarchical trust management for WSNs. The model is mainly applied to the hierarchical wireless sensor networks. Cluster nodes and cluster head nodes choose different trust factor, then they will use their own reputation calculation model to get the reputation and use the trust management to achieve the trust model based on hierarchical trust management for wireless sensor networks.Whether the node can correctly transmit of data is the basis of the WSNs applications, so the node communication trust is selected as the trust factor. Node energy factor is the key to restricting the WSNs applications, so the node energy trust is selected as the trust factor. Whether the data has the consistency that is got by compares with other node data and historical data is s factor to determine the node is working, so data consistency is the trust factor of the node in the cluster. During reputation calculation process of the cluster head node, energy trust and communication trust will be selected as trust factor. The cluster head will select the communication trust and energy trust as the trust factor.The reputation of node which in the cluster is obtained by communication reputation, energy reputation, data consistency and been weighted integrated. The reputation of cluster head node is obtained by communication reputation and energy reputation and been weighted integrated. The cluster head node is responsible for the management of the reputation of the nodes in the cluster. Cluster head nodes manage the reputation for each other. On this basis and combined with the reputation calculation model, node reputation will take the updated measures in a given period of time, and the model will introduce punishment and reward mechanism. Take to reduce the reputation of active node and reduce the chance of participating in the data communications. The reputation of low competitive node will be increased and increases its chance to participate in date communications.Simulation results show that the trust model based on hierarchical trust management for wireless sensor networks is able to respond to most security threats and has a good robustness. In contrasted experiment with the traditional trust model, the new model can be more accurate, objective come to the reputation of the node and to extend the network lifetime. Due to the introduction of punishment and reward mechanism, the model able to respond to the internal network threats and improves the network stability.