Research On AODV Routing Protocol Against Blackhole Attack

Mobile ad hoc networks are widely used in military and civilian environments such as battlefield communications,post-disaster rescue,and temporary meetings.However,due to their inherent lack of centralization,terminal limitations,and wireless links,they are prone to various security issues.Among them,blackhole attack is a network layer attack that frequently occurs in the AODV routing protocol.Blackhole nodes lure source nodes to transmit data packets to them by responding with false routing information and then directly discard the received data packets,thereby affecting network performance.A traditional method based on the basic idea of using asymmetric cryptographic mechanisms to confirm the route with the destination node has two problems: 1.In order to ensure that the routing information possessed by the source node is fresh enough,the destination node needs to frequently perform encryption calculations,which increases the computational load of the destination node,increases routing overhead,and can easily cause network congestion.2.Simply confirming the route with the destination node cannot determine that the intermediate node responding to the route is a malicious node.In response to the above two problems,a secure routing protocol based on route index confirmation,IAODV,is proposed based on the traditional method.IAODV is divided into two stages.In the route index confirmation stage,the source node is ensured to have a certain degree of fresh routing while reducing the computational load of the destination node.In the suspicious node positioning stage,suspicious nodes are located through the idea of route endpoint positioning for untrusted route responses and broadcasted throughout the network.Finally,the blackhole nodes are determined through the isolation buffer mechanism.The simulation experiment of IAODV using NS2 shows that under different changing scenarios,IAODV has better performance compared to the traditional method,indicating the effectiveness and robustness of IAODV.In order to further reduce the computational load of the destination node and the delay of IAODV,a route-value-based RVAODV routing protocol is proposed based on IAODV.By quantifying the route reply from three aspects: residual energy level,congestion degree and normalized hop count,the route value is obtained and used as one of the criteria for judging the freshness of the route.The path with higher route value is preferentially selected for data transmission.Experiments show that RVAODV has reduced computational load and delay compared to IAODV,verifying the effectiveness of RVAODV.