Defence Mechanism for SYBIL Attacks in MANETS using ABR Protocol

Security is of paramount concern in any adhoc network. In Mobile Adhoc NETworks (MANETs), mobility of the nodes poses a problem for providing security services [1]. The ad-hoc network is more vulnerable to attacks, since it uses wireless communication link between the mobile nodes. Sybil Attack is a spoofing attack, where a malicious node illegitimately creates multiple fake identities (called the Sybil nodes) to impersonate as normal nodes. It is observed that most of the existing protocols fail to defend against Sybil attack. Associativity Based Routing (ABR) protocol is an on-demand active routing protocol. It chooses the most long lived and stable route for communication rather than the shortest route. In this paper, using ABR protocol, we show that a legitimate node in the network along with the Local Server (LS) can detect the Sybil attacker. We show through simulation that using the concept of a PKI secured SESSION KEY (SESS_KEY), we can detect the presence of a Sybil attacker in the network. The empirical results show that there is an increase of 10% in the throughput and 60% in good put and the integrity of the network. This would lead to a more secure communication network with a reduced overall delay.