Transmission-efficient group-key generation in large dynamic MANET environments

Cryptographic key-management in a large dynamic environment such as mobile ad hoc network is a challenging task due to the limited availability of communication resources in wireless domain. This paper describes a novel key-management system using cluster-based group multicasting technique. The method employs Identity-based threshold-cryptographic group-key share distribution among participating nodes to form a secure group. There exist several clusters in each group to generate combined group key share using aggregate signcryption. The clusters inside same group collaborate with each other to generate a combined group-secret-share at cluster level and then contact with other clusters for mutual exchange of the combined group-secret-share to produce the final group key. This approach reduces the number of required encrypted transmitted messages containing group key shares. The scheme is highly applicable to other distributed dynamic environments with high security demand.