A per-hop security scheme for highly dynamic wireless sensor networks

Certain popular wireless sensor network applications, including disaster recovery, battlefield communication and athlete monitoring, are characterized by extensive node mobility, intermittent contact between nodes and a highly dynamic network topology. Traditional routing protocols and security schemes are designed for essentially static networks and do not perform well in this case. This has given rise to a new multi-hop routing paradigm, that of ldquomobility-assistedrdquo routing in which nodes make strategic data store-and-forward decisions on a per-hop basis. In this paper we discuss the security challenges relevant to mobility-assisted routing and propose a scheme to secure data communication between nodes in highly mobile sensor networks. Our solution utilizes symmetric-key encryption to ensure data confidentiality and varies encryption key in a verifiable, non-forgeable manner to allow easy authentication. This scheme also provides data freshness, semantic security and per-hop encryption to enable secure data aggregation. To validate our basic assumptions and fine-tune our scheme, we collect and analyze link connectivity statistics from a dynamic sensor network application, athlete monitoring during a first-division university soccer club match. We show that our scheme is well-suited for certain dynamic environments and serves as an effective first step towards securing communications for mobile sensor networks.