Is Really NACK Protocol Secure to Be Employed in MANETs?

MANET, which stands for Mobile Ad-hoc Network, is composed of a group of self-organized and wireless nodes that do not possess any predictable and fixed infrastructure. When nodes want to communicate with each other, they have to pass on their messages directly or indirectly. In case the destination node is out of the transmission range, the source node has to rely on intermediate nodes, which, in this case, is called indirect transmission. On the other hand, if the destination node is the neighboring node, there is no need to employ intermediate nodes, which, in this case, is called direct transmission. Over the past years, security issues in MANETs have received a great deal of attention due to their extensive applications in, for instance, disaster relief efforts, military battlefields, conference venues, and so on. Because of that, quite a few protocols have been proposed in this realm. In this paper, it is tried to analyze NACK protocol from the security standpoint. NACK was proposed by Sun et al. In 2012. Unfortunately, the proposed scheme not only has some technical problems, it is vulnerable to the man-in-the-middle attack as well, which is a kind of routing misbehavior attack. In the end, some countermeasures are proposed against the mentioned flaw and vulnerability.