Multiple trust sources may be needed for broadcast in wireless ad hoc networks. For example, multiple base stations may be employed in some wireless sensor networks, or multiple trusts may be distributed among multiple routing nodes in multi-hop routing protocol. Most of the previously proposed multicast/broadcast authentication protocols assume a single source of trust. With multiple trust sources it becomes difficult to design a resource-efficient authentication protocol for multicast/broadcast services. Simply extending traditional approaches will result in increased bandwidth and memory consumptions in proportion to the number of trust sources. We propose a new scheme utilizing Combined Key Chains (CMC). If there are m trust sources, our scheme generates m+1 key chains, where m of them are distributed among the m source nodes and the last one is used as a verification key chain in all the receiver nodes. The communication overhead is small and constant, and the memory requirement at a verifier node is also minimal.

Seonho Choi is currently a Professor and Chair in the Department of Computer Science at Bowie State University, USA. His primary research interests lie in the computer and network security. In 1991, he received a B.S. in Computer Science and Statistics from Seoul National University in Korea and a Ph.D. in Computer Science in 1997 from the University of Maryland, College Park, USA.