Security in Wireless Ad Hoc and Sensor Networks

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Challenges and Solutions: Basic Issues

There are a number of security challenges associated with wireless ad hoc and sensor networks, and we introduced them in Chapter 7. In contrast to guided media, the wireless medium is openly accessible, less reliable and has no obvious physical boundary. An attacker does not need to break any physical barriers to gain access to the wireless medium and can enter the network from anywhere and from all directions. In addition, more complications in security establishment come from the dynamically changing topology, the reliance on node collaboration for network connectivity, the lack-of-trust infrastructure and the lack of a clear line of defense. Since ad hoc networks are built without a fixed infrastructure and centralized management, the protection mechanisms used in tethered networks cannot be adopted directly in wireless ad hoc and sensor networks.

In a secure wireless ad hoc sensor network, a node is authorized by the network and only authorized nodes are allowed to access the network resources. The generic process to establish such a network consists of bootstrapping, pre-authentication, network security association establishment, authentication, behavior monitoring and security association revocation. Among these, authentication is of the utmost importance and is an essential service in network security. Other basic security services like confidentiality, integrity and nonrepudiation depend on authentication. Secret information is ...