Evolving Secret Sharing: Hierarchical Access Structure with Polynomial Share Size

摘要

Secret sharing allows storing secret information in a distributed manner among several participants. The original setting of secret sharing schemes assumes that the total number of participants does not change from the very beginning. However, we need to consider the scenario where any time a new participant can join, and the total number of participants is (possibly) unbounded. Evolving secret sharing solves the problem, and secret sharing for evolving threshold access structure has been considered in the last few years. In this paper, we study multi-level access structures, and more specifically, evolving compartmental and hierarchical access structures. We provide concrete constructions with the estimation of share sizes.