An Efficient Member Expansion Protocol for Threshold Schemes

In this paper, an efficient member expansion protocol for threshold schemes is presented. The protocol can generate new shares for new members in threshold schemes. In addition, the old members need not change their shares after distribution. It is convenient for secret management. The new members can verify whether her share is right or not in this protocol. The new protocol is very efficient, which only needs 2t+1 times broadcast to generate and distribute the new share as opposed to 6t times in Dong´s protocol and 4t+1 times in Li´s protocol. Furthermore, very few broadcasting data are needed in the presented protocol. It means the new protocol is especially useful in wireless environments.