Adaptive ACKnowledgement technique with key exchange mechanism for MANET

Mobile Adhoc NETwork (MANET) is self configuring network of mobile nodes connected by wireless links and it is considered as network without infrastructure. Routing protocol in MANET operates on the basic assumption that nodes are fully cooperative. Because of open infrastructure and limited battery power some nodes may not cooperate correctly. These nodes start refusing to forward data packets or drop them thereby degrades the performance of network. So it is very essential to develop an Intrusion Detection System (IDS) to prevent MANET from attacks. The IDS Watchdog, fails to detect node misbehavior in the presence of ambiguous collisions, receiver collisions, limited transmission power, false misbehavior, collusion and partial dropping. An intrusion detection system named Enhanced Adaptive ACKnowledgment (EAACK) has been developed which consists of three parts, namely, ACK, Secure ACK (S-ACK), and Misbehavior Report Authentication (MRA). All the acknowledgement packets are digitally signed and verified to prevent forged acknowledgement packets. For signing and verifying the acknowledgement packets, keys are generated and distributed in advance. The proposed system uses One-hop ACK which is used to improve misbehavior detection rates. Basic drawback of S-ACK includes it cannot distinguish exactly which particular node is misbehaving node. Sometime well behaving nodes became a part of misbehaving link. Thus lot of well behaved node may be avoided by network which results in losing of well behaved routes. To eliminate the requirement of predistributed keys proposed system considers Diffie-Hellman Key Exchange Algorithm.