Tree and elliptic curve based efficient and secure group key agreement protocol

Abstract

Group Key Agreement Protocol (GKAP) is a cryptographic mechanism where members of a group agree on a common key by sharing their blinded keys over a public channel. Sharing a key over a public channel is a security threat and expensive in terms of communication cost. In this paper, we proposed the GKAP based on tree and elliptic curve. For reducing the communication cost, we have used the divide-and-conquer mechanism with that group is divided into small subgroups and forming a tree-like structure. The modified Elliptic-Curve-Diffie–Hellman used for sharing the blinded key over a public network channel securely. This paper discussing different group key management operations are initialization, join, mass join, leave, mass-leave, merge with their communication cost are the number of rounds, unicast cost, broadcast cost, messages. This paper discussing the establishment of common keys not only for the group but also for the subgroups. Based on communication cost, we have compared the performance of proposed method with the existing approaches like Communication-Computation Efficient Group Key Algorithm (CCEGK), Tree-based group key agreement (TGDH), Ternary-tree based group key agreement protocol for dynamic group (TTGKAP), Group key generation tree protocol (GKGT), Ternary tree-based group key agreement protocol over elliptic curve for dynamic group (TTEGKAP), Efficient Group key agreement using hierarchical key tree (EGKAKT). From performance analysis, it is cleared that proposed approach performed better in most of the cases than the existing approaches. The proposed approach is safe against passive attack, collaborative attack, forward secrecy, backward secrecy, and man-in-the-middle attack.