An Efficient Threshold Signature Scheme Without Random Oracles

We present a robust threshold signature scheme which is provably secure without random oracles under the computational Diffie-Hellman assumption. Our construction derives from a novel application of the recent signature scheme due to Waters. Compared with Wang et al.´s threshold signature scheme without random oracles, the signing procedure of our scheme is much more efficient in terms of communication and computation. In fact, our threshold signature scheme´s efficiency is comparable to Boldyreva´s threshold signature scheme which is provably secure in the random oracle model (ROM).