一种新的动态批密钥更新算法

针对传统单次密钥更新方法存在低效、资源浪费、数据和密钥不同步等问题,提出了一种基于密钥树的批密钥更新算法.通过2种方法保持密钥树的平衡:利用加入节点替代离开节点的位置来保持树的结构不变;搜索密钥树中高度最低的节点,然后根据该节点的类型及剩余的可加入节点数,将适量的节点加入到高度最低节点的位置.同时,对服务器的更新开销进行了理论分析,建立了用于计算开销的精确数学模型.仿真实验表明,与单次密钥更新方法相比,所提算法可以将更新开销减少74.6%,显著提高更新效率,并适合于大型动态群组的应用.

A Novel Dynamic Batch Rekeying Algorithm

Aiming at the problems that the traditional individual rekeying approach is inefficient,waste of resources,and out-of-sync between keys and data,a novel batch algorithm for renewing keys is proposed based on a key tree.In the new algorithm,the key tree is kept balanced by two methods:departed nodes are replaced by joining nodes to keep the structure of the tree un-changed;the node with the smallest height in the tree is searched,and then a proper number of joining nodes are added to the node place based on the type of the node and the number of the re-maining nodes to be joined.The cost of renewing servers'keys is analyzed theoretically,and ac-curate mathematical models are established to calculate the COSt.Simulation results and compari-son with the individual rekeying approach show that the proposed algorithm decreases the rekey-ing cost by 74.6 % and improves the efficiency of rekeying significantly,and that the algorithm is suitable for large dynamic groups.