We present a password-authenticated group key exchange protocol where each user has his/her own password. Advantage of such protocol is in short passwords, which can be easily memorized. On the other hand these protocols face the low password entropy. In the first part we define security model based on models of Abdalla, Fouque and Pointcheval and Bellare, Pointcheval, Rogaway. We construct the...

Protocols for group key exchange are cryptographic algorithms that allow a group of parties communicating over a public network to come up with a common secret key. One of the interesting results of research on group key exchange is the protocol compiler presented by Abdalla et al. in TCC ’07. Abdalla et al.’s compiler shows how one can transform any authenticated 2-party key exchange protocol ...

People need to communicate each other in many emerging networks, i.e., in ad hoc networks. To ensure the security for group communication, group key management as a fundamental cryptographic primitive has been proposed. Although many proposals with regard to group key managemet have been introduced, they cannot be efficiently applied to realize secure subgroup and intergroup communications. In ...

Group key transfer protocols depend on a mutually trusted key generation center (KGC) to transport the group key to all group members secretly. This approach requires that a trusted sever be set up, and it incurs communication overhead costs. In addition, the existing group key transfer protocols based on secret sharing all use threshold schemes that need to compute a -degree interpolating poly...

In recent years, group-oriented applications and collaborative protocols are gaining popularity. This calls for group key management which forms the basic building block in achieving secure group communication. The points that differentiate it from the traditional communication are that they do not have a centralized server but a distributed system, group key being contributory and dynamic natu...

An authenticated group key exchange (AGKE) scheme allows a group of users in a public network to share a session key which may later be used to achieve desirable cryptographic goals. In the paper, we study AGKE schemes for dynamically changing groups in ad hoc networks, i.e., for environments such that a member of a group may join and/or leave at any given time and a group key is exchanged with...

In key management schemes that realize secure multicast communications encrypted by group keys on a public network, tree structures are often used to update the group keys efficiently. Selçuk and Sidhu have proposed an efficient scheme which updates dynamically the tree structures based on the withdrawal probabilities of members. In this paper, it is shown that Selçuk-Sidhu scheme is asymptotic...

: The need for rapidly configurable, secure communication among groups of participants has resulted in the study of group key agreement protocols. The study of these protocols has been primarily theoretical. In this paper, we present the results of simulation studies of the methods provided by four group-key agreement protocols, EGK, TGDH, STR and CCEGK. The results of the simulation clarify th...

Two schemes for key distribution in a computer network are presented in [ 11. Given a network of N users, these schemes allow the construction of group keys and master keys for each of the 2N N 1 subgroups of two or more users from only O(N) pieces of secret information. Agrroup key allows the members of a group to communicate among themselves; a master kq allows the holder to compute group key...

Traditionally, research in secure group key agreement focuses on minimizing the computational overhead for cryptographic operations, and minimizing the communication overhead and the number of protocol rounds is of secondary concern. The dramatic increase in computation power that we witnessed during the past years exposed network delay in WANs as the primary culprit for a negative performance ...