Multiparty key agreement for secure teleconferencing

Multiparty key agreement has many applications on internet services such as secure teleconferencing. A group of users can hold a conference securely over an open network by running a multiparty key agreement protocol to generate a common secret key. With the common secret key, data transmission over the internet is protected for confidentiality. In 2003, Barua (INDOCRYPT 2003) first proposed a multiparty key agreement protocol by using Weil pairing. The protocol is based on ternary trees and Joux's tripartite key agreement. However, in Barua's protocol the communication round for n entities is [log(3)(n)], which is proportional to the number of participants. In this paper, we propose a new multiparty key agreement protocol from Weil pairing that needs only constant number of rounds. Besides, the message size, the total number of scalar multiplications, and the number of Weil pairing are reduced.