Unconditionally secure key assignment schemes Original Research Article

In this paper we propose an information-theoretic approach to the access control problem in a scenario where a group of users is divided into a number of disjoint classes. The set of rules that specify the information flow between different user classes in the system defines an access control policy. An access control policy can be implemented by using a key assignment scheme, where a trusted central authority (CA) assigns an encryption key and some private information to each class.