Many basic key distribution schemes specifically tuned to wireless sensor networks have been proposed in the literature. Recently, several researchers have proposed schemes in which they have used group-based deployment models and assumed predeployment knowledge of the expected locations of nodes. They have shown that these schemes achieve better performance than the basic schemes, in terms of connectivity, resilience against node capture and storage requirements. But in many situations expected locations of nodes are not available. In this paper we propose a solution which uses the basic scheme, but does not use group-based deployment model and predeployment knowledge of the locations of nodes, and yet performs better than schemes which make the aforementioned assumptions. In our scheme, groups are formed after deployment of sensor nodes, on the basis of their physical locations, and the nodes sample keys from disjoint key pools. Compromise of a node affects secure links with other nodes that are part of its group only. Because of this reason, our scheme performs better than the basic schemes and the schemes using predeployment knowledge, in terms of connectivity, storage requirement, and security. Moreover, the post-deployment key generation process completes sooner than in schemes like LEAP+.
In this paper we propose an approach for key management in sensor networks which takes the location of sensor nodes into consideration while deciding the keys to be deployed on each node. As a result, this approach not only reduces the number of keys that have to be stored on each sensor node but also provides for the containment of node compromise. Thus compromise of a node in a location affects the communications only around that location. This approach which we call as location dependent key management does not require any knowledge about the deployment of sensor nodes. The proposed scheme starts off with loading a single key on each sensor node prior to deployment. The actual keys are then derived from this single key once the sensor nodes are deployed. The proposed scheme allows for additions of sensor nodes to the network at any point in time. We study the proposed scheme using both analysis and simulations and point out the advantages.