D-VKT: A Scalable Distributed Key Agreement Scheme for Dynamic Collaborative Groups

Jiang ZHANG  Li-Feng SUN  Yun TANG  Shi-Qiang YANG  

IEICE TRANSACTIONS on Communications   Vol.E90-B   No.4   pp.750-760
Publication Date: 2007/04/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.4.750
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Networks Software)
distributed key agreement,  collaborative group,  Virtual Key Tree,  

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Key agreement for collaborative groups has become an increasingly popular research area. However, most of previous work requires each member to not only maintain the whole key tree structure whose size is O(N), where N is the size of group, but also involve rekeying operation upon each membership change, resulting in high costs in terms of storage, communication and computation and thus suffers from poor scalability. In this paper, we propose a scalable Distributed and collaborative group key agreement scheme using a Virtual Key Tree (D-VKT). Each group member in D-VKT only reserves and maintains partial information of the whole key tree structure with requirement of O(log N). Furthermore, a distributed tree balancing algorithm is presented to keep the whole key tree as balanced as possible for rekeying efficiency. In addition, a distributed group batch rekeying protocol is proposed to further reduce the computation and communication workload of group rekeying in a highly dynamic environment. The experiment results demonstrate that D-VKT can scale to large and dynamic collaborative groups.