Abstract 

The open nature of the wireless medium leaves it vulnerable to intentional interference attacks, typically referred to as jamming. This intentional interference with wireless transmissions can be used as a launch pad for mounting Denial-of-Service attacks on wireless networks. Typically, jamming has been addressed under an external threat model. However, adversaries with internal knowledge of protocol specifications and network secrets can launch low-effort jamming attacks that are difficult to detect and counter. In this work, we address the problem of selective jamming attacks in wireless networks. In these attacks, the adversary is active only for a short period of time, selectively targeting messages of high importance. We illustrate the advantages of selective jamming in terms of network performance degradation and

adversary effort by presenting two case studies; a selective attack on TCP and one on routing.We show that selective jamming attacks can be launched by performing real-time packet classification at the physical layer. To mitigate these attacks, we develop three schemes that prevent real-time packet classification by combining cryptographic primitives with physical-layer attributes. We analyze the security of our methods and evaluate their computational and communication overhead.

Wireless local area networks (WLANs) are becoming an increasingly important technology that is approaching the world. WLANs are used in every area, such as education, agriculture, pharmaceuticals, manufacturing, transportation, military, and research. Therefore, the importance of WLAN security is significant. There are two popular WLAN styles: client-server networks and ad-hoc networks. The difference between these two networks is that client-server networks use access points or routers to transmit data, but ad-hoc networks do not depend on any pre-existing transmitter. Instead, all nodes in an adhoc network participate in the routing process by sending messages to each other. According to the Institute of Electronic and Electronic Engineers (IEEE) 802.11g standards (IEEE Org., 2012), all wireless network nodes transmit packets of data in different channels. Since the channels in the WLANs are defined by the frequencies, they are susceptible to malicious interference attacks. It is easy for attackers to manage to send multitudes of useless packets on a specific frequency. Blocking attacks attempt to lock the system by flooding it with useless traffic and use all network resources so that users on the network can not connect to the system. It is constantly used by hackers to break down network systems due to ease and security issues. In this case, sis, clienterver and ad-hoc networks were simulated using the OPNET Modeler simulation tool (OPNET Technologies, Inc., 2012). During the simulation, factors that may influence the simulation result, such as distance, power level and protocols used in ad hoc networks were taken into account.