An efficient distributed group key management using hierarchical approach with Diffie-Hellman and Symmetric Algorithm: DHSA

This paper proposes an efficient many-to-many group key management protocol in distributed group communication. In this protocol, group members are managed in the hierarchical manner logically. Two kinds of keys are used, asymmetric and symmetric keys. The leaf nodes in the key tree are the asymmetric keys of the corresponding group members and all the intermediate node keys are symmetric keys assigned to each intermediate node. For asymmetric key, Diffie-Hellman key agreement is introduced. To calculate intermediate node keys, members use codes assigned to each intermediate node key tree. Group members calculate intermediate node keys rather than distributed by a sponsor member. The features of this approach are that, no keys are exchanged between existing members at join, and only one key, the group key, is delivered to remaining members at leave.