Abstract
Guaranteeing security of the sensor network is a challenging job due to the open wireless medium and energy constrained hardware. Jamming style Denial-of-Service attacks is the transmission of radio signals that disrupt communications by decreasing the signal to noise ratio. These attacks can easily be launched by jammer through, either bypassing MAC-layer protocols or emitting a radio signal targeted at blocking a particular channel. In this chapter, we survey different jamming attack models and metrics, and figure out the difficulty of detecting and defending such attacks. We also illustrate the existed detecting strategies involving signal strength and packet delivery ratio and defending mechanisms such as channel surfing, mapping jammed region, and timing channel. After that, we explore methods to localize a jammer, and propose an algorithm Geometric-Covering based Localization. Later, we discuss the future research issues in jamming sensor networks and corresponding countermeasures.
TopJamming Attack Models And Metrics
Jamming attack is a kind of Denial of Service attack, which prevents other nodes from using the channel to communicate by occupying the channel that they are communicating on (W. Xu, 2005). We define the jammer in wireless sensor network as an entity who is purposefully trying to interfere with the physical transmission and reception of wireless communications. A typical scenario of jamming attack is shown in figure 1. The normal nodes C and D has been jammed by the malicious node X, so the communications between the jammed nodes(C, D) and the normal nodes (A, B, E, H, I) are disrupted.
Figure 1. An example of Jamming attack in WSN
Key Terms in this Chapter
Signal Strength: The value of received signal strength indicator
Jamming Attack: A kind of Denial of Service attack, which prevents other nodes from using the channel to communicate by occupying the channel that they are communicating on
Smallest Circle Covering: The smallest circle covering, simply speaking, is the problem of finding the smallest circle that completely contains a set of points. Formally, given a set Q of n planar points, find the circle C of smallest radius such that all points in Q are contained in either C or its boundary.
FHSS: Frequency Hopping Spread Spectrum
Mapping Service: Nodes near the border of a jammed region notify neighbors outside of the region of jamming
DSSS: Direct Sequence Spread Spectrum
Timing Channel: A low bit-rate overlay that exits on top of the conventional physical/link layers and that would survive in the presence of a persistent broadband jammer
Packet Delivery Ratio: The ratio of packets that are successfully delivered to a destination compared to the number of packets that have been sent out by the sender
Channel Surfing: The nodes that detect themselves as jammed should immediately switch to another orthogonal channel and wait for opportunities to reconnect to the rest of the network
Convex Hull: The convex hull of a set of Q of points is the smallest convex polygon P for which each point in Q is either on the boundary of P or in its interior. We denote the convex hull of Q by .
Wormhole-based Anti-Jamming: A path which called probabilistic wormhole to guarantee that, for the given randomly located jammer, there is a positive probability that a sensor node residing in the jammed region of an attacker forms a path from such a region to the area not affected by jamming