Study And Design Of Node Trust Evaluation Algorithm In Ad Hoc Networks

Ad Hoc networks as wireless communication technologies can not dependent on network infrastructure and are capable of rapid deployment. Because of its non-central, self-organization, multi-hop routing, dynamic topology and other characteristics, it can well meet the needs of military applications, sensor networks, emergency situations and so on. Especially, with the development of new technologies such as things,vehicle networking,4G, SDN, Ad Hoc networks have a growing range of applications.However, compared to the traditional networks using hierarchical architecture and with stable topology management mechanisms, Ad Hoc networks as special mobile networks are more susceptible to proactive intrusion, passive monitoring and other network attacks due to the inherent characteristics, the use of wireless channel, limited energy and distributed control technology. Especially, one mobile terminal itself can act as a router, security issues will become more prominent. Traditional network security policy or mechanism does not apply to the Ad Hoc network. Therefore, it is the key to design security measures for Ad Hoc networks to ensure their applications.This paper firstly discusses many security issues in Ad Hoc networks application processes, as well as security and trusted relationships, further study and introduce the concept of trust, as well as the nature and the model. Furthermore, on this basis, existing schemes including malicious node detection and node trust evaluation have been studied and analyzed, and we proposed a high-performance algorithm of node trust evaluation to Identify malicious nodes in networks. This program requires the network nodes are offline prior to joining the network to get only a legal certificate. Only nodes with legal certificates can participate in the network communications. When a node in Ad Hoc networks is evaluated and determined to be a malicious node, its certificate will be revoked. Moreover, the node will be refused to participate in the network service by other nodes in the network.Firstly, this scheme modifies the network routing protocol called AODV which has some drawbacks to solve trust problems. A node within the network can directly evaluate its neighbour nodes’ behavious through listening to whether data packets which should be routed by them are forwarded. If a node detects its neighbouring nodes with malicious behaviours and will broadcast accusations against them. Every node has a relative accusation weight based on its trust level in the network. By further quantify the trust evaluation of the accused nodes, it can form revocation shares of its certificate revocation. One malicious node is evaluated as an untrusted node as only as its certificate revocation sharesare greater than or equal toits revocation threshold. In order to reduce the damage on network performance because of malicious behavious, just only one accusation can limit the accusation function ofthe accused node. In order to enhance theaccuracy of node trust evaluation, the trust evaluation to one node should consider multiple nodes’accusation weights. In addition, this scheme requires nodes justaccept those accusations in which trust levels of accuser nodesare not less than accused nodes’ in one correct node accusation relationship.In order to guarantee the rapidity of node trust evaluation, after revoking the certificateof one node,trust levels of nodes who have accused the nodewill be improved, accusations made by them will have enhanced trust evaluation results to the rest malicious nodes, and the accusation functions of legitimate nodes which are just falsely accused by it can be restored This scheme is validated through the network simulator NS2, and simulation results show that the node trust evaluation algorithm which was proposed by us can quickly and accurately determine the malicious nodes in the network in a variety of scenarios, significantly improving the network quality of service.