Self-organizing security scheme for multi-hop wireless access networks

A multi-hop wireless access network can provide a rapidly deployable, mobile communications infrastructure that is suitable for many sensor network scenarios. In particular, such a network based on the IEEE 802.11 wireless local area network (WLAN) protocols can be economically built allowing sensors equipped with standard network interface components to communicate. However, improved security for these extended multi-hop WLANs is required. In this paper, the WPA protocol for security on an IEEE 802.11 WLAN is extended to operate on an ad hoc wireless multi-hop network. A method is described for applying the WPA protocol beyond the single-link case for which it was defined, to a store-and-forward wireless network. In particular, the secure nomadic wireless network (SNOWNET) system is described that implements a collection of access networks interconnected via a wireless ad hoc backbone network. Each SNOWNET node is a router that has both an access service and a wireless backbone interface. The backbone is automatically formed as an ad hoc network among the routers using MANET-style routing schemes for data forwarding. The security method described provide data protection and authentication for client users, attached sensor devices and for the routers that may dynamically join and exit from the backbone network.