Scalable Authenticated Dynamic Group Key Agreement Based on Multi-Tree

In this paper, we present a scalable authenticated dynamic group key exchange protocol based on an m-branch tree (m > 3) where we first assume that m is generic and can identify the specific value of m finally depending on the actual application environment. Compared to others based on binary and ternary trees, our protocol reduces the height of key tree and rounds efficiently, therefore it is more scalable and suitable for large groups in ad-hoc network. In our scheme based on multi-tree, m sibling nodes at most at the same level agree on a key of their corresponding father node in the above level by invoking the protocol (DB) that Dutta and Barua presented. On the other hand, our scheme is authenticated and efficient in terms of communication and computation power through extending DB protocol that is provably secure under the Decision Diffie-Hellman (DDH) assumption in the standard model to dynamic group key agreement based on multi-tree.