Efficient secret sharing with access structures in a hierarchy

In 2004, Chang et al. suggested an approach that solves the problem of secret sharing with access structures in a hierarchy. They used the concept of discrete logarithm to reuse shadows, and adopted Cho´s (Cho et al., 2001) mechanism to achieve the properties of hierarchical key management. However, Chang´s scheme requires a lot of time for computation. In this paper, we adopt one-way hash function to allow the shadows to be reused and achieve the properties of hierarchical access control. The proposed scheme is more efficient than Chang´s scheme.