Auto defence mechanism for SYBIL attacks in MANETs using QABR protocol

The paramount concern in any adhoc network is Security. In Mobile Adhoc NETworks (MANETs), providing security services poses a problem due to the mobility of the nodes. The ad-hoc network uses wireless communication link between the mobile nodes and hence is more vulnerable to attacks. In Sybil Attack a malicious node creates illegitimate multiple fake identities (called the Sybil nodes) to impersonate as normal nodes. Most of the existing protocols fail in defending against Sybil attack. Associativity Based Routing (ABR) protocol is a reactive on-demand routing protocol which chooses the most long lived and stable route. In this paper, using QABR (Q-Learning Based ABR)protocol, we show that an honest node in the network along with the Local Server (LS) can detect the Sybil attacker, using the concept of a PKI secured unique key called the SESSION KEY (SESS_KEY). The route being chosen is made a stable route by using the idea of associativity ticks (A_th) which is calculated using the concept of Q-learning. The inclusion of Q-learning based network management agents improves the Quality of Service (QoS). The observed empirical results show that there is an efficient increase of 15% in the throughput and the integrity of the network and a considerable reduction in the route establishment time. The accumulated work reduces overall delay, thereby leading to a more secure communication network.