Authorization model based on object-oriented concept

In object-oriented systems, classes and objects are hierarchically structured in instance-of, is-a, and part-of relations. Data and methods of a class are inherited by lower-level classes according to the is-a hierarchical structure. Access rules on classes are specified to make sure that only authorized subjects manipulate objects in authorized ways. It is difficult to specify access rules for every class and object, because the system is composed of various types of classes, and objects which are dynamically created and dropped. If access rules on some class could be reused for other classes, the access rules are easily specified. This paper discusses how to inherit access rules in the hierarchical structure of classes and objects.