A key-chain-based keying scheme for many-to-many secure group communication

We propose a novel secure group keying scheme using hash chain for many-to-many secure group communication. This scheme requires a key predistribution center to generate multiple hash chains and allocates exactly one hash value from each chain to a group member. A group member can use its allocated hash values (secrets) to generate group and subgroup keys. Key distribution can be offline or online via the key distribution protocol. Once keys are distributed, this scheme enables a group member to communicate with any possible subgroups without the help of the key distribution center, and without having to leave the overall group, thus avoiding any setup delay. Our scheme is suitable for applications where the population of a system is stable, group size is moderate, subgroup formation is frequent, and the application is delay sensitive. Through analysis, we present effectiveness of our approach.