Secure routing based on distributed key sharing in large-scale sensor networks

Abstract

Sensor networks, usually built with a large number of small, low-cost sensor nodes, are characterized by their large-scale and unattended deployment, necessitating “secur ” communications between nearby, as well as remote, sensor nodes for their intended applications and services. Key setup/sharing is crucial to the protection of such applications/services from attacks, but existing (public-key, cluster-based, or pairwise) solutions become too expensive (hence, inefficient) when the underlying applications/services require communications between distant sensor nodes. To remedy this inefficiency, we propose a novel distributed key-sharing scheme, in which each participating sensor node shares unique keys with a small number of other sensor nodes—called distributed key servers (DKSs)—chosen according to their geographic distance and communication direction. Using DKSs, we develop two secure routing protocols: (1) secure geographic forwarding that delivers packets by using a chain of DKS lookups, each secured with its own key and forwarded geographically; and (2) key establishment that creates a secure session between two distant sensor nodes based solely on symmetric-ciphers. These protocols enable low-cost, low-power sensors to provide high-level security at a very low cost.