A Novel Approach towards Cost Effective Region-Based Group Key Agreement Protocol for Ad Hoc Networks Using Elliptic Curve Cryptography

This paper addresses an interesting security problem in wireless ad hoc networks: the dynamic group key agreement key establishment. For secure group communication in an ad hoc network, a group key shared by all group members is required. This group key should be updated when there are membership changes (when the new member joins or current member leaves) in the group. In this paper, we propose a novel, secure, scalable and efficient region-based group key agreement protocol for ad hoc networks. This is implemented by a two-level structure and a new scheme of group key update. The idea is to divide the group into subgroups, each maintaining its subgroup keys using group elliptic curve diffie-hellman (GECDH) Protocol and links with other subgroups in a tree structure using tree-based group elliptic curve diffie-hellman (TGECDH) protocol. By introducing region-based approach, messages and key updates will be limited within subgroup and outer group;hence computation load is distributed to many hosts. Both theoretical analysis and experimental results show that this Region-based key agreement protocol performs well for the key establishment problem in ad hoc network in terms of memory cost, computation cost and communication cost.

Authenticated Diffie-Hellman Key Agreement Protocol with Forward Secrecy

Forward secrecy is an important security property in key agreement protocol. Based on Ham＇s protocol, in this paper a new authenticated Diffie-Hellman key agreement protocol with half forward secrecy is proposed. This protocol is also based on a single cryptographic assumption, and is user authentication and shared key authentication. More importantly, our protocol provides forward secrecy with respect to one of the parties. For this reason, besides the advantages of Ham＇s protocol, in practice, our protocol can reduce the damages resulted from the disclosure of the user＇s secret key and it is very beneficial to today＇s communication with portable devices.