| The jamming attack is one of the serious threats to wireless sensor networks (WSNs) using the IEEE 802.15.4 standard. In such an attack, jammers, who launch the attack, can dramatically degrade the network performance by interfering transmitting packets. Therefore, the study of the jamming attack and its countermeasures has become an important aspect of the WSN security.;First, we present an energy-efficient Reduction-of-Quality ( EERoQ) attack against coordinators to prevent them from receiving normal packets from neighbors. In EERoQ, attackers use periodic jamming signal to block the transmission of data packets or ACK frames. In our model, an attacker can maximize damage per unit cost by maximizing the attack potency which is defined to be the ratio of the damage caused by attackers to the cost of launching EERoQ. In EERoQ, the generation of jamming signal is one of the critical technologies to launch the attack. Therefore, we present a strategy for implementing jamming signal by exploiting the CSMA-CA mechanism. Our experiments on an IEEE 802.15.4 compatible sensor network show that the proposed attack strategy is an energy-efficient way to implement the RoQ attack.;Second, we present an effective dynamic jamming attack (EDJam ) in an 802.15.4-compliant WPAN and use the Stackelberg game to formulate the dynamic procedure of competition between the EDJam attacker and defending networks. In the proposed attack, a jammer who is aware of a change in the network defense strategy may choose a better strategy to make more damage to the network with less cost. Similarly, a well-protected network can change its defense strategy against the EDJam. Therefore, a Stackelberg game can precisely reflect the procedure of a dynamic jamming attack and network defense. The simulation results show that EDJam can be more cost-efficient than continuous, random and fixed-period jamming.;Finally, we describe an energy-efficient keyless DSSS (EUDSSS) proposed for energy-constrained wireless networks. We proposed the EUDSSS to balance the capacity of jamming-resistance and overhead by maximizing the tradeoff between correct bit rate and the additional communication bits comparing with traditional DSSS. The simulation results show that EUDSSS can achieve adequate reliability with small overhead. |
