Tolerant Key Assignment for Enforcing Complicated Access Control Policies in a Hierarchy

Abstract

In 1998, Yeh et al. proposed a flexible key assignment scheme for enforcing complicated access control policies in a user matrix model. Later, Hwang indicated that Yeh et al.' scheme is susceptible to some security flaws. Thus, Lin et al. proposed a key assignment scheme for enforcing complicated access control policies in a hierarchy. However, there exist drawbacks in Lin et al.'s scheme: lack of efficiency and a large variation of the keys. Hence, we propose an efficient key assignment scheme in a hierarchy for enforcing the complicated access control policies. What is more, the secret key of one class is allowed to be changed several times without influencing the derivation key in our proposed scheme.