A Flexible Communication of Group Key Agreement.

Key transfer protocols rely on a mutually trusted Group Key Agreement (GKA ) to select session keys and transport session keys to all communication entities secretly. Most often, GKA encrypts session keys under another secret key shared with each entity during registration .In this paper, we propose an authenticated key transfer protocol based on secret sharing scheme that GKA can broadcast group key information to all group members at once and only authorized group members can recover the group key; but unauthorized users cannot recover the group key. The confidentiality of this transformation is information theoretically secure. We also provide authentication for transporting this group key. Goals and security threats of our proposed group key transfer protocol will be analyzed in detail. A Group Key Agreement (GKA) protocol is a mechanism to establish a cryptographic key for a group of participants, based on each one's contribution, over a public network and allows a set of players to establish a shared secret key which can be used to secure a subsequent communication. The key, thus derived, can be used to establish a secure channel between the participants. When the group composition changes (or otherwise), one can employ supplementary GKA protocols to derive a new key. Group key agreement is a fundamental building block for secure peer group communication systems.