Cryptanalysis of an ID-based Authenticated Dynamic Group Key Agreement with Optimal Round
Qingfeng Cheng, Chunming Tang · International journal of network security · 2015
Recently, Teng, Wu and Tang proposed a new ID-based authenticated dynamic group key agreement (DGKA) protocol. They claimed that leaving users cannot calculate subsequent group session keys and joining users cannot calculate previous group session keys. In this paper, we will show that Teng et al.’s protocol cannot provide forward condentiality or backward condentiality.