Weiser (1991) envisioned ubiquitous computing with computing and communicating entities woven into the fabrics of every day life. This chapter deals with the survivability of ambient resource-constrained wireless computing nodes, from fixed sensor network nodes to small devices carried out by roaming entities, for example, as part of a personal area network of a moving person. First, we review the assets that need to be protected, especially the energy of these unplugged devices. There are also a number of specific attacks that are described, for example, direct physical attacks are facilitated by the disappearing security perimeter. Finally, we survey the protection mechanisms that have been proposed with an emphasis on cryptographic keying material and trust management.
Key Terms in this Chapter
Static Keying: Means that the nodes have been allocated keys off-line before deployment, that is, predeployment.
To Eject: Means that the sensor increases the power of transmission to be able to reach the base station in one transmission.
Rekeying Overhead: The network traffic needed to establish a new key.
Network Resilience: The number of captured nodes before an attacker is able to control the network.
Reactive Routing Protocols: Compute the route between two nodes only when the route is needed, that is, ‘on demand.’
Node: A node may go from the tiny fixed deployed sensor to the mobile unplugged mobile device.
Trust: Trust ‘is a subjective assessment of another’s influence in terms of the extent of one’s perceptions about the quality and significance of another’s impact over one’s outcomes in a given situation, such that one’s expectation of, openness to, and inclination toward such influence provide a sense of control over the potential outcomes of the situation’ (Romano, 2003).
Node(s) Survivability: Emphasises that the scope of the nodes mission may span more than one node. The survivability of the node itself may be more important than the survivability of the other nodes or the mission may be that the majority of the nodes survive at the expense of the survival of one specific node.
Energy-aware Routing Protocols: Explicitly take into account the energy consumption as a parameter.
Computed Trust Value: A nonenforceable estimate of the entity’s future behaviour in a given context based on evidence (“Trustcomp,” n.d.).
Network Connectivity: The probability that two nodes can communicate.
Dynamic Keying: Means that the keys can be (re)generated after-deployment.