Mitigation of Blackhole attack in MANET

Mobile ad hoc network (MANET) is a technology of spontaneous creation of ad hoc network for data exchange, in which nodes can act as end nodes or can act as router. In hostile environment some node may deny to forward packet in order to disrupt regular communications, this type of abnormal behavior is referred as packet drop attack or blackhole attack. Most of the techniques that are used to mitigate blackhole attack are based on the use of destination sequence number as a criterion to identify blackhole node. However, these schemes have limitation of quantifying the value of destination sequence number that is used to identify a blackhole node. As a result, attacker can change the value of destination sequence number according to value present in RREQ (Route REQuest) packet. In the proposed approach we have used hop count value to identify a blackhole node. This hop count is utilized by means of confirmation packet in this scheme. The advantage of proposed work is that blackhole node is not identified based upon destination sequence number value. The proposed work has been implemented in QualNet and result shows that blackhole node is identified.