Li Baohong,Hou Yibin,Zhao Yinliang
(School of Electronics and Information Engineering,Xi'an Jiaotong University,Xi'an 710049,China)
Abstract:Aiming at the scalability of rekeying in secure multicast,an improved logic key hierarchy mechanism is proposed.When a key tree is updated,the key server produces random numbers,and all or the part of new keys in update paths are directly calculated by the multicast group members using one-way hash function.Therefore,the burdens of the computation and communication for updating keys through multicast channels are decreased.It is estimated that the key server's average cost can be reduced by about 1/3.A batch update algorithm is also presented in the paper based on the improved scheme,in which changing of members several times can be carried out only by update operation once.It is shown by experiments that the key server's cost of this algorithm can be reduced again at least 1/3．So the performance is further improved when this batch update algorithm is applied to the improved scheme．
Keywords:secure multicast;session key update;key tree;one-way hash function