Communications in mobile reconnaissance mission systems require secure wireless sensor networks (WSNs). How should efficient and secure remote procedure calls (RPCs) be designed and implemented to allow servers to stipulate access policy and oblige clients to validate their identities? Chapin and Skalka present SpartanRPC, a secure middleware technology with an application programming interface (API) for controlling access to resources in WSNs. SpartanRPC permits network administrators to specify security policies for reconciling access to resources by network nodes with different security domains.

SpartanRPC, an extension of the nesC programming language, is used to specify interfaces for duties, authorizations, remote services, dynamic wires, and RPCs. A resource is a user-defined functionality for accomplishing a task. Interfaces that look like commands are duties used to specify remote services for dynamically communicating among neighboring nodes in WSNs. Remote types are inherent arithmetic types in nesC. A remote interface delivers duties with remote argument types. Remote component nodes have unique identifiers and manager interfaces that serve as the dynamic wiring endpoints. Dynamic wiring among components of a nesC program allows the specification of control flow from duty invocation to its implementation. A Diffie-Hellman security protocol is used in the system to authenticate access to resources by clients. Elliptic curve cryptography (ECC) signatures are initially applied to validate the SpartanRPC certificates of network communicating entities.

The authors concisely present a security policy language predicated on a distributed trust management system, and an authorization model that reflects interactions between servers and clients. The implementation of a secure directed diffusion with multihop data collection in SpartanRPC is discussed, to illuminate the support of the link-layer RPC service for network-layer communication. Client-server message communication programs and an environmental monitoring system were used to assess the performance of the system. The current system implementation is susceptible to denial of service (DoS) attacks and hardware intrusion. The memory and processing time attributed to the implementation of the security protocols is excessive. Nonetheless, SpartanRPC is reliable for many everyday WSN applications such as mobile medical emergency communication systems.