Abstract-To accomplish secure group communication, it is essential to share a unique cryptographic key among group members. The underlying challenges to group key agreement are scalability, efficiency, and security. In a dynamic group environment, the rekeying process is more frequent; therefore, it is more crucial to design an efficient group key agreement protocol. Moreover, with the emergence of various group-based services, it is becoming common for several multicast groups to coexist in the same network. These multicast groups may have several shared users; a join or leave request by a single user can trigger regeneration of multiple group keys. Under the given circumstances the rekeying process becomes a challenging task. In this work, we propose a novel methodology for group key agreement which exploits the state vectors of group members. The state vector is a set of randomly generated nonce instances which determine the logical link between group members and which empowers the group member to generate multiple cryptographic keys independently. Using local knowledge of a secret nonce, each member can generate and share a large number of secure keys, indicating that SGRS inherently provides a considerable amount of secure subgroup multicast communication using subgroup multicasting keys derived from local state vectors. The resulting protocol is secure and efficient in terms of both communication and computation.Index Terms-Group key agreement, resource sharing, multicast security, dynamic system, scalability, confidentiality, rekeying
I. INTRODUCTIONN the recent past with the advent of fast networking technologies, there has been a profound increase in the speed of the Internet and the degree of connectivity. In addition, with the emergence of new Internet applications such as video conferencing, online joint workspaces, group chat, multi-user games and online social networking applications, numerous possibilities for group communications have been created. Group participants share common interests and share the responsibility of secure group communication. In group communication, agreement regarding a secure group key is one of the most important and challenging tasks. Specifically, to maintain a secure group key in a dynamic environment This work was supported by the ICT R&D program of MSIP/IITP. [R-20160302-003082 becomes more difficult as the reestablishment of the group key should be rapid and lightweight with regard to complexity. Secure rekeying becomes an even more challenging task in resource-limited networks such as wireless sensor networks (WSNs) [1] and body-area networks (WBAN) [2], as most conventional cryptographic mechanisms and security protocols are not suitable for resource-limited WSNs or WBANs. For example, very efficient public key algorithms, such as ECC [3], need a fraction of a second to execute encryption/decryption procedures, while a symmetric key algorithm such as RC5 [3] needs only a fraction of a millisecond to perform encryption and decryption procedures [4][5]. For computa...