Efficient large-scale distributed key generation against burst interruption

A distributed key generation scheme allows the key servers to distributively share a secret key and then compute the corresponding public key. Canny and Sorkin (Canny and Sorkin, 2004) proposed a probabilistic threshold distributed key generation scheme that is suitable for the case that the number of key servers is large. The communication cost of their scheme is much less than that of previous schemes. Nevertheless, it is possible to improve their scheme in some aspects. In this paper we employ the randomness technique to cope with some problems encountered by their scheme. Our contribution is twofold. Firstly, our scheme is secure against a large cluster of dishonest key servers. Secondly, our scheme has better performance in some aspects. We support this point by a series of simulation experiments. As a result, our scheme and Canny and Sorkin's scheme can be used in different situations.