Repairable Threshold Secret Sharing Schemes

Abstract

In this paper, we propose a class of threshold secret sharing schemes with repairing function between shares without the help of the dealer, that we called repairable threshold secret sharing schemes. Specifically, if a share fails, such as broken or lost, it will be repaired just by some other shares. A construction of such repairable threshold secret sharing schemes is designed by applying linearized polynomials and regenerating codes in distributed storage systems. In addition, a new repairing rate is introduced to characterize the performance and efficiency of the repairing function. Then an achievable upper bound on the repairing rate is derived, which implies the optimality of the repair and describes the security between different shares. Under this optimality of the repair, we further discuss traditional information rate and also indicate its optimality, that can describe the efficiency of secret sharing schemes in the aspect of storage. Finally, by applying the minimum bandwidth regenerating (MBR) codes, our construction designs repairable threshold secret sharing schemes achieving both optimal repairing and information rates simultaneously.