Quaternary Tree Group Diffie- Hellman Based Group Key Management Protocol for Dynamic Peer Groups

Abstract

Diffie-Hellman (DH) protocol for 2-party has made the key exchange to be simple yet powerful. It is widely used in many communication-oriented protocols for establishing the keys in public communication channels. With millions of internet users connected globally and using various group oriented applications, communication among them has to be in a secured manner. Due to its simplicity, DH has been further extended to group setting and number of protocols are developed. Establishing Group Key and regenerating it during membership changes is a challenging task in communication among large groups. This paper proposes a quaternary tree method that uses the key tree concept and Group Diffie Hellman protocol, GDH.3 to establish the common key. GDH.3, an extension of DH for n parties is best suited for large dynamic groups. Quaternary tree reduces the height almost by half as against binary trees, making the rekeying much easier. As the group size increases, GDH.3 outperforms other existing group protocols based on DH, since it requires much lesser number of exponentiations.