Key distribution in mobile heterogeneous sensor networks

Key predistribution is a popular technique for key distribution in sensor networks. The existing predistribution schemes are designed for nodes with no or limited mobility. The existing schemes make use of only one key pool to establish links between the stationary and the mobile nodes. This restricts the mobility of nodes to one specific network. If the same key pool is used in multiple networks, the compromise of keys in one network would lead to compromise of keys in all the networks. We present two different solutions to this problem. The first approach uses a separate disjoint key pool to establish links between the stationary and mobile nodes of the network. In the second approach we take a large key pool and segment it into smaller key pools. Each of these segments acts as the key pool for different stationary sensor networks. The mobile nodes get keys from the aggregate of all these segments. The aggregate key pool can have some segments which can be used for future deployments. We compare the two schemes and analyze their performance. It is assumed that the stationary nodes of the sensor networks are securely connected.