Second European Symposium on Research in Computer Security (ESORICS 92)
Type-Level Access Controls for Distributed Structurally Object-Oriented Database Systems
Udo Kelter
Keywords : views, discretionary access controls, object-oriented database systems, distribution, multiple inheritance, group-orientation, access control lists
Abstract : Structurally object-oriented database systems are a new class of dedicated data storage systems which are intented to form the basis of CAD, CASE and other design environments which are to support large, distributed development teams. Several concepts of discretionary access controls (DAC) for such systems have been proposed; these concepts support nested complex objects and nested working groups. However, they do not support roles in development teams such as designers, reviewers, managers, etc., whose access rights are typically given in terms of object types rather than only in terms of objects. This paper presents a concept of type-level DAC which is intended to complement the instance-level DAC and to support roles in development projects. The concept consists of a formal model of the state of the object base with regard to access controls and a formula which derives from this state and the security context of a process the type-rights of this process. Our model has virtually no built-in, enforced policies; it allows users to realize a wide range of application-specific security policies. It supports multiple inheritance; in order to prevent inconsistent rights on types with common subtypes, certain consistency constraints are introduced. The model is group-oriented in that it supports nested working groups and inheritance of rights along group hierarchies. Access to individual types can be explicitly denied. It is implementable in a distributed system; the administration of rights can be fully decentralized.
(Pages 21-40)