Efficient Star Topology based Multicast Key Management Algorithm

Problem statement: Secure group communication is very important for many applications such as internet pay sites. It provides efficient delivery of identical data to only the customers in the group. In large and dynamic multicast groups, the group keys of members have to be changed frequently whenever the member leaves or joins. A common method is to apply a symmetric key that is used to encrypt the transmitted data. The rekeying cost scales linearly with the number of members in the group and cost of the rekeying process is the main issue. The tree-based architecture is commonly used to reduce the rekeying cost in terms of storage, transmission and computation. But it usually gives extra overhead to balance the tree which is in order to achieve logarithmic rekeying cost. Approach: The main aim was to use star topology based architecture to avoid the balancing and eliminate the rekeying processes and more over it was more secured by exchanging the secret key between only server and each group member. The features of proposed algorithm were that the private key was computed by individual member. Results: The burden of server was reduced and also there was no rekeying when a member leaves the group. The secret value of leaving member was not added in the encryption and so the private value could not be obtained after decryption. Conclusion: Proposed algorithm is simple and no rekeying when a member leaves and also reduces the computation and communication complexity.