An improvement on conference key agreement protocol with user anonymity

From the idea of conference key distribution was first proposed by Ingemarsson et al., many conference key distribution schemes were proposed. Conventionally, a conference key distribution system (CKDS) is used to distribute a conference key among the attending participants of a conference. Compared with most existing CKDS, conference key agreement protocol with user anonymity has more application and more fair property for unbiased decisions. In 2005, Kim et al. proposed a new conference key agreement scheme with anonymity. However, in the current paper, we will point out Kim et al.'s scheme involved unnecessary computation costs for the participants, and it is not one fair conference key agreement scheme. We also give an improvement of Kim et al.'s scheme.