一个群签名成员删除方案的分析和改进

Analysis and improvement of the group signature member deletion scheme

在群签名系统中群成员随时都可能离开,所以如何有效删除成员是一个重要的研究课题.王尚平等提出的成员删除方案(王删除方案)虽然其计算复杂性与成员删除数量无关,但笔者证明其不能达到真正删除成员的目的.基于王删除方案选择参数时所依据的数学原理,把成员注册和删除时的特性密钥更新算子由公开转为保密,同时特性密钥的更新工作由成员执行交由群主管执行,从而达到真正删除成员的目的,而且改进方案的计算量和原方案一样.

In a group signature system, the group members can leave at any time. Therefore how to delete a member efficiently is an important research topic. Wang et al. presented an efficient member deletion scheme （Wang deletion scheme） whose Computation complexity is irrelative to the numbers of group member deleted, but we prove that it can not delete group members really. Based on the mathematical principle by which to choose parameters in the Wang deletion scheme, the improved one turns the renewing operator of the characteristic key which is used in registration and deletion from publicity to secrecy, and shifts the renewing work from the group member to the group administrator. By the improved scheme, the group members can be deleted effectively without increasing the computation complexity.