A lightweight group-key management protocol for secure ad-hoc-network routing

Secure routing protocols for ad hoc networks use group keys for authenticating control messages without high energy consumption. A distributed and robust group-key management is, thus, essential. This paper proposes and specifies a protocol for distributing and managing group keys in ad hoc environments based on the Secure Optimized Link State Routing protocol (SOLSR). The proposed protocol manages group keys taking into consideration frequent network partitions/mergers and also reduces the impact of non-authorized users that try to illegitimately obtain the group key to use network resources. The analysis shows that our proposal provides high availability and presents low energy consumption for the two most important group events in ad hoc network: joining-node events and network-partition-merging events. Our protocol reduces both the number of control messages and the energy spent with cryptographic operations by up to three orders of magnitude when compared to contributory group-key agreement algorithms. The proposed protocol provides an efficient key management in a timely manner.