A Multi-Level Secret Sharing Scheme Based on Semigroup Structures
基于半群结构的多等级密钥分享方案

How to securely distribute a company's secret key to its n authorized departments is of much importance in information management system of E-commerce. In many cases, every authorized department in a company needs a partial or sub-secret key, and each person in the corresponding authorized department has an access level to the sub-secret key. Upon the sub-secret key of a department being cooperatively reconstructed, the company's secret key can be securely and completely reconstructed from all sub-secret keys of the departments. This paper presents such a novel multi-level secret sharing scheme. Instead of traditional method, this scheme is mainly based on the complexity of semigroup structures in which each department's sub-secret key is related to a group and each person's access level in the corresponding department is characterized by an order of an element in the group. The proposed scheme can also be employed to other scenarios where multi-level secret sharing is needed.