Availability Evaluation And Stability Analysis On Malicious Program In Heterogeneous WSNs

With the rapid development of communication technology,Heterogeneous Wireless Sensor Networks(HWSNs)have been widely used in urban management,military,computer and other fields.HWSNs are usually set up in an unmanned and vast special environment without supervision,so nodes are easy to be captured and there are many potential threats.All of the above situations put forward higher requirements for the security performance of heterogeneous WSNs,which makes the performance evaluation of heterogeneous WSNs particularly urgent and important.Therefore,this dissertation studies the availability and stability on malicious program in HWSNs.The main contents are as follows:(1)Based on the similarity between the transmission mode of virus in the classical infectious disease model and the diffusion process of malicious programs in HWSNs,the SEQIRD malicious program propagation model is constructed.The proposal of this new model makes the description of the state of heterogeneous sensor nodes more in line with the actual situation.(2)The semi-Markov process is applied to the SEQIRD malicious program propagation model to evaluate the performance index of the availability of HWSNs.A situation where a node containing a malicious program is used as an attacker to launch a continuous attack on a node within its communication range is considered,which causes the vulnerability of the node to change.The semi-Markov chain is used to describe the dynamic transition process between each state of the node.Meanwhile,the state transition probability matrix and the steady-state probability of each state are obtained,which lead to the availability calculation formula of a single heterogeneous sensor node is inferred.Considering the characteristics of different topological structures of HWSNs,the availability calculation formula of the entire HWSNs under star,cluster and Mesh structures is inferred.The effects of initial infection rate,infection change rate,recovery rate and the composition of different topological structures on the availability of HWSNs are analyzed experimentally,and the effectiveness of the proposed method is verified.(3)The stability of the SEQIRD model is quantitatively analyzed for HWSNs with different communication connectivity of sensor nodes.The transition process between the node states satisfies the propagation dynamics equation,and thus a set of differential equations that can describe the transition of the node states is obtained.It also proves that the propagation model has a stable point and the stability of the stable point.At the same time,the threshold of whether the malicious program spreads or disappears in the HWSNs is obtained by calculation.Then combined with simulation experiments,the correctness of the model stabilization at the disease-free stable point and the influence of the transition probability between node states on the propagation process are verified.