Research On Detection And Defense Mechanism Of Malicious Attacks In Internet Of Things Environment

Internet of things is a large heterogeneous network,which can connect a large number of micro devices to Internet according to agreed protocols and realize intelligent communication between any objects.It can complete daily tasks with little human intervention.However,since most Internet of Things devices are limited in terms of CPU,memory capacity,battery life and other resources,researchers rarely consider the security of these devices at the beginning of their design,and the security mechanism in the traditional network is often not applicable to Internet of things,which makes Internet of things face severe challenges in terms of security.Therefore,it has become one of the most important tasks in the field of Internet of Things research to design a security protection mechanism that can take into account both security and energy consumption and can deal with various malicious attacks.This paper focuses on the contradiction between security and energy consumption in Internet of things,packet dropping attack(including blackhole attack and greyhole attack)in the routing process,and greyhole attack in the case of node movement.The specific research work is as follows.1)For the problem of overhead waste of data source authentication in traditional static security mechanism,a trust-based adaptive security mechanism is proposed first.Before the relay node performs data source authentication on the received message,the trustworthiness between nodes is comprehensively evaluated,and data source authentication is performed only on messages sent from untrusted nodes,thereby reducing the energy overhead of the relay node.Meanwhile,in order to prevent On-off attack nodes from cheating the trust of legitimate nodes and damaging the network maliciously,another trust-based adaptive detection algorithm is proposed to monitor those nodes whose trust value exceeds the trust threshold in real time,so as to achieve the purpose of defending against On-off attack.2)For the problem of packet dropping attack in Internet of things,on the basis of RPL routing protocol,a trust-based security routing mechanism is proposed.According to the behavior of nodes in data forwarding,a trust evaluation model between nodes is established,and the fuzzy set theory is used to classify the trust relationship between nodes.Neighbor nodes with higher trust level are selected for routing nodes to forward data,while neighbor nodes with lower trust level are isolated from the network.In addition,in order to avoid normal nodes being isolated from the network as malicious nodes due to some non-intrusion factors,a certain recovery time will be provided for such nodes to further determine whether to isolate them from the network,thus reducing the error detection rate.3)For the problem of greyhole attack in case of partial node movement,a detection method is proposed.This method adopts Expected Transmission Count to calculate the dynamic threshold value of node packet loss rate,so as to selected the suspicious greyhole node and marks it to the isolation area.When the number of times that the routing node is marked into quarantine area is up to the upper limit,the sink node performs Sequential Probability Ratio Test on the node to further determine whether the node is a greyhole node.Finally,the grayhole node is eliminated through the global repair mechanism in RPL routing protocol.