Preventing Wormholes in Multi-hop Wireless Mesh Networks

Wireless Mesh Networks (WMNs) has become an emerging technology in recent days due to its easy deployment and low setup cost. In WMN, Routing protocols play an important role and these are susceptible to various kinds of internal attacks. One such attack that has severe impact on a WMN is a wormhole attack. A Wormhole is a low-latency link between two parts of the network through which an attacker tunnels network messages from one point to another point. In this paper, we specifically focus on wormhole attack launched by colluding nodes referred to as Byzantine wormhole attack. Unfortunately, most of the existing wormhole defense mechanisms are either centralized, or rely on additional hardware. The major challenge in detecting a byzantine wormhole link is the inability to distinguish nodes involved in the attack process, as they form the legitimate part of network. Being legitimate part of the network, they can bypass all security mechanisms and timing constraints imposed by the network. In this paper, we propose a mechanism to prevent byzantine wormhole attack in WMNs. The proposed mechanism relies on digital signatures and prevents formation of wormholes during route discovery process and it is designed for an on-demand hop-by-hop routing protocol like HWMP (Hybrid Wireless Mesh Protocol-the default routing protocol for WMN). This is simplistic and also applicable to source routing protocols like DSR. This is a software based solution and does not require additional (or) specialized hardware.