Improved Secret Sharing with Access Structures in a Hierarchy

In 2004, Chang et al. presented an approach firstly to solve the problem of secret sharing with access structures in a hierarchy. After that, based on one way hash function, another proposed scheme was suggested by Lin et al. However, there is the same drawback in both schemes. When group secret keys need to be changed, the trust authority has to update related parameters of each branch in both the above schemes. In this paper, using discrete logarithm, an improved secret sharing with access structures in a hierarchy is given. It can achieve the property that related parameters do not have to update even if group secret keys are altered. So, the presented scheme may be more suitable for applications