Abstract: The migrating towards wireless network from wired network has become latest popular global trend in past few decades. The versatile properties of wireless networks created it possible in countless applications. Involving all of the contemporary wireless networks, Mobile Adhoc NETwork (MANET) provides essential and unique applications. Because of its awesome abilities like mobility, scalability and self configuration, the MANET has been wide spread in many applications like military, rescue operations, some tactical conditions and the like. The intrinsic nature of Adhoc networks makes them vulnerable to various passive and active attacks and thus it is vital to build an efficient intrusion detection mechanism to protect MANET from attacks. Prevention methods for attacks alone are not sufficient to make them secure. So, Intruders have to be detected at the early stages of data transmission. To acquire security we are proposing A Novel Intrusion detection system (NIDS) named Enhanced Adaptive ACKnowledgement (EAACK) is introduced for Insider Attackers (IA) in MANETs by using normal end to end ACK scheme, Secure ACK (S-ACK) and Misbehavior report Authentication (MRA) scheme. The proposed system eliminates the existing system weaknesses like Receiver Collision, Limited Transmission power and false misbehavior report. EAACK yields better results compared to all modern techniques for misbehavior detection by reducing the routing overhead and by increasing the network performance. The three parts of EAACK (ACK, SACK and MRA) are acknowledgement based detection systems. To detect the misbehaviors in the network, the three schemes rely on ack packets. All ack packets are authentic and untainted. Otherwise the attackers forge the ack packets. So, we include Digital Signature in EAACK to ensure the integrity of Intrusion Detection system.

Keywords: MANET, Insider attack, Digital Signature Algorithm (DSA), MRA.