Research On Trust Model Of Grouping And Hierarchical For Wireless Sensor Networks

There are more and more security problems in Wireless Sensor Networks because sensor nodes are resource-constrained and usually deployed in a bad environment. Encryption-based security mechanisms can resist external attacks, but they can't resolve internal attacks that caused by nodes been captured sometimes. Therefore, we need to establish an effective trust mechanism for distinguish captured nodes from networks timely. Trust model based communication is applied to Wireless Sensor Networks currently, but it can't solve the security threats and energy shortage problem. Fully centralized trust models are not appropriate because they are energy expensive due to extra routing overhead. Fully distributed trust models are also not suitable because they have limited computing capacity and memory and so on. How to save energy and memory of the node and establish a wireless sensor network of node more reliable are the key issues of this paper.In this paper, we propose a trust model of grouping and hierarchical, in which the nodes are grouping by cluster. By considering the different trust factors, and then calculate the trust values of the cluster nodes, cluster heads and base stations hierarchically. The model only based on communication trust was not enough to decide on the trustworthiness of a node, because relative to other types of networks, the nodes of WSNs not only have communication capabilities, they also have unique monitoring, sending reports and receiving data capabilities. Besides, the energy of nodes also affects the lifecycle of the entire network. Thus, when we evaluate the trustworthiness of nodes, the trust model will consider the data and energy factors according to the specific needs. In this way, a trust model based communication, data and energy is to build a more reliable environment. Furthermore, compared with completely centralized and fully distributed trust model, the model calculate and store the trust values of nodes in different levels using an appropriate method, try to simplify the calculation process and avoid' excessive routing and memory overhead.Simulation results show that the model only based on communication trust was not enough to decide on the trustworthiness of a node and the trust model of grouping and hierarchical could judge the credibility of a node more simply and accurately. The trust model of grouping and hierarchical is lightweight which can identify and discard malicious nodes effectively to ensure network security, keep minimum resource utilization and enhance the stability of the network.