Secure communication in Mobile Ad Hoc Networks (MANETs) is important as nodes communicate over the wireless medium, which can be easily eavesdropped. Currently, the literature of secure IP address autoconfiguration in MANETs is extremely rare. In this paper, we propose five protocols that provide both secure IP address autoconfiguration and authenticated group key agreement (GKA) to give a more efficient and secure solution for MANET communications. Whenever a dynamic group membership event such as node join, node leave, network merge and network partition occurs, our protocols ensure that the IP address allocation table and group key are updated so that there are no address conflicts and leaving and joining users cannot decrypt future and previous communications respectively. A complexity analysis shows that despite having additional capabilities such as IP address autoconfiguration and key authentication, our protocols are still efficient when compared to other GKA protocols.

Recently, Dutta and Barua proposed provably secure constant round authenticated group key agreement protocols in dynamic scenario. In this letter, we show that their Leave Protocol does not provide forward secrecy, that is, a leaving user can still obtain the new session key used in subsequent sessions.