The pervasive usage of the Internet has made secure group communications a significant issue. Conference-key agreement protocols provide secure group communications with lower computational cost. Providing key agreements and updates of dynamic groups in an efficient manner is a significant challenge for conference-key agreement protocols. Auxiliary key agreement operations are needed to solve the challenge. In this paper, we propose an improved conference-key agreement protocol, called Dynamic Conference-Key Agreement Protocol, that consists of Initial Conference-Key Agreement Protocol and Auxiliary Conference-Key Agreement operations. Dynamic Conference-Key Agreement Protocol has operations to handle dynamic groups. The proposed protocol has better fault correction and provides the same security level with the existing ones. Copyright (c) 2014 John Wiley & Sons, Ltd.