Date Added: Jul 2010
This paper proposes dealer-free dynamic secret sharing constructions where different parameters of the scheme can be changed after the initialization. In practice, the ability of the adversary might be enhanced over time, for instance, by compromising more players. A possible solution to this problem is to increase the threshold and/or change the secret. On the other hand, another common problem with almost all secret sharing schemes is that they are one-time in the sense that after secret recovery both the secret and shares are known to everyone. This problem can be resolved if the dealer shares several secrets at the beginning. The authors apply existing tools and develop some new techniques to tackle these problems.