A provably secure threshold signature scheme based on DDH assumption

Threshold signature is an important cryptographic primitive, which was introduced by Desmedt and Frankel in 1991. In a (t, n) threshold signature scheme, a group secret key is distributed among n parties. Later, any t or more parties can use their shares of secret key to generate valid signatures on behalf of the group, while any t - 1 or less parties cannot. Over the past years, many excellent threshold signature schemes have been proposed, but few of them provide the provable security proof. Therefore, in this paper, based on Decisional Diffie-Hellman (DDH) assumption, we present a new (t, n) threshold signature scheme and use the techniques from provable security to analyze its security. Copyright (C) 2010 John Wiley & Sons, Ltd.