适用于动态群组的密钥树平衡技术  

Balancing the key tree for dynamic groups

作　　者：王巍[1] 马建峰[1] 杨超[1] 赵文红[2] 

机构地区：[1]西安电子科技大学计算机网络与信息安全教育部重点实验室,陕西西安710071 [2]西安电子科技大学理学院,陕西西安710071

出　　处：《西安电子科技大学学报》2008年第3期483-489,共7页Journal of Xidian University

基　　金：国家自然科学基金资助(60573035,60573036,60633020);国家自然科学基金重大项目资助(90204012)

摘　　要：在群组密钥管理中,基于密钥树的方法可以达到对数级别的密钥更新代价而被广泛采用.但随着群组成员的加入和离开,密钥树会变为不平衡的结构,这时需要对密钥树进行平衡操作.提出了一种适用于动态群组的改进的平衡密钥树.在对成员加入或离开事件进行处理时,基于此密钥树的群组密钥管理方案不使用借用孩子结点、节点融合和结点分裂技术.提出的方案满足群组密钥保密性、前向保密性、后向保密性和密钥独立性等安全属性,且在最差的情况下和权重平衡树具有相同的密钥更新代价.分析结果表明提出的方案在成员加入和离开时所需的更新代价分别为O(2h)和O(2h2).Abstract： In group key management, the approach based on the key-tree is widely used to achieve logarithmic rekeying costs. However, the key tree may become unbalanced after inserting or deleting members, and has to be kept balanced. In this paper, an improved balanced key tree is presented for dynamic groups. In the scheme based on the proposed tree, the balancing tree after member adding or member deleting does not involve borrowing a child from a sibling, merging with a sibling, and splitting a node. The scheme based on the proposed tree satisfies the desired properties, such as group key secrecy, forward secrecy, backward secrecy, key independence, and has the same worst case rekeying cost as a weight-balanced-tree. Our analysis shows that the rekeying costs of the presented scheme are O（2h） and O（2h^2） in the join event and the leave event respectively.

关 键 词：群组密钥 群组密钥管理 密钥树 平衡树 动态群组 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]