Tiered Authentication of Multicast Traffic in Wireless Ad-Hoc Networks

Multicast streams are the dominant application traffic pattern in many mission critical ad-hoc networks. The limited computation and communication resources, the large scale deployment and the unguaranteed connectivity to trusted authorities make known security solutions for wired and single-hop wireless networks inappropriate for such application environment. This paper promotes a novel Tiered Authentication scheme for Multicast traffic (TAM) for large scale dense ad-hoc networks. Nodes are grouped into clusters. Multicast traffic within the same cluster employs one-way chains in order to authenticate the message source. Cross-cluster multicast traffic includes a message authentication codes (MACs) that are based on a set of keys. Each cluster uses a unique subset of keys to look for its distinct combination of valid MACs in the message in order to authenticate the source. TAM thus combines the advantages of the secret information asymmetry and the time asymmetry paradigms and exploits network clustering to reduce overhead and ensure scalability. The numerical and analytical results demonstrate the performance advantage of TAM.