Cost Effective Rekeying Approach for Dynamic Membership Changes in Group Key Management

Security is an important requirement in reliable group communication over open networks in order to prevent intruder attack. A common secret key called group key is generated for encrypting the group information. A distributed key management methodology based on dynamic decentralized group key agreement protocol is required to handle this issue. Rekeying or new group key generation is based on membership driven or time driven. Rekeying is needed whenever a new single member comes to the group or an existing member goes out. Individual rekeying operations in a large group of users leads to the increase the rate of message exchanges which leads to performance degradation. This paper investigates communication rounds, computation complexity and storage of keys in existing key management schemes and introduces an enhanced decentralized Sub Group Key Management (SGKM) approach which is efficient for rekeying. In the proposed work, a group is fragmented into sub groups and the sub groups are managed with one encryption key and multi decryption key protocol by the respective manager. The performance of proposed algorithm is analyzed under different join and leave possibilities.