Secure Route Discovery for Preventing Black Hole Attacks on AODV-Based MANETs

Mobile Ad-hoc Networks (MANETs) allow mobile hosts to initiate communications with each other over a network without an established infrastructure or a central network authority. Because of this, MANETs have dynamic topologies because nodes can easily join or leave the network at any time. From a security design perspective, MANETs are vulnerable to various types of malicious attacks. As are result, Ad-hoc On-demand Distance Vector (AODV), which is one of the standard MANET protocols, can be attacked by malicious nodes. A black hole attack is one type of malicious attack that can be easily employed against data routing in MANETs. A black hole node replies to route requests rapidly with the shortest path and the highest destination sequence number. The black hole node does not have an active route to a specified destination associated with it and it drops all of the data packets that it receives. This paper proposes a mechanism that provides Secure Route Discovery for the AODV protocol (SRD-AODV) in order to prevent black hole attacks. This mechanism requires the source node and the destination node to verify the sequence numbers in the Route Request (RREQ) and Route Reply (RREP) messages, respectively, based on defined thresholds before establishing a connection with a destination node for sending the data. The simulation results using the Network Simulator 2 (NS2) demonstrate an improvement in the ratio of packet delivery for three different environments using our mechanism as compared to the standard AODV protocol.