A fault-tolerant and secure multi-conference-key agreement protocol

This paper describes a threshold multi conference-key distribution scheme based on a (t, n) secret sharing scheme. Whenever the number of participants from a. group is larger than or equal to a predetermined threshold value t, the legitimate participants can obtain the conference-keys after the reconstruction stage. In contrast to other conventional schemes such as those presented respectively by Shamir and Feldman where the necessary shares must be distributed secretly to the participants in the initialization stage, our proposed scheme relies on public-key infrastructure. In particular, the predetermined threshold can be modified easily without changing the predetermined conference keys. Furthermore, we show that our scheme is efficient and robust, and the passive and active adversaries neither gain information about the conference-key established by the honest participants nor disrupt conference-key establishment.