On the Security of Chang et al.s' Cryptographic Key Assignment Scheme for Access Control in a Hierarchy

Abstract

In 1992, Chang, Hwang and Wu proposed a cryptographic key assignment scheme based on Newton’s Interpolation method and a predefined one-way function to solve the access control problem in a user hierarchy. In this paper, we shall show that their scheme is problematic in controlling access to all types of hierarchical organizations. Furthermore, we show that their scheme is not secure enough by presenting an attack on it.