Openly available communication signals, in wireless
adhoc network poses high security risk. The adhoc networks
are very much vulnerable to Dos attacks on the network
layer. Blackhole and Grayhole attacks are the widespread
attacks on adhoc networks. Here the malicious nodes
interrupt data transmission in the network by transmitting false
routing information. A realization of these enabled us to
approach the subject of data security in wireless adhoc networks
with a different perspective so as to have a communication route,
free from all previously mentioned security threats. The purpose
of this paper is to present an efficient Adhoc On-demand
Distance Vector (AODV) protocol that removes the malicious
node by isolating it, thereby ensuring secure communication. In
order to achieve this goal, the intermediate nodes receiving false
routing information from its neighbour node is programmed to
consider that neighbour node as malicious. In adhoc network,
nodes can join or leave at any time. So, an efficient security
mechanism is needed. So, the nodes are arranged in spanning
tree fashion. An RSA key exchange and two encryption
techniques are used among authenticated neighbours in the
adhoc network to provide more security and thus avoid group rekeying
problems.