The Implementation of Secure Entity-Relationship Databases

A database management system supporting the Entity-Relationship model has been implemented to provide secure, controlled sharing of information within a user community. This paper describes the security requirements of the users, and how they have been implemented in the DBMS. In the basic security policy, each user belongs to one or more œaccess groups´. Each resource can be accessed only by members of a specific access group. This policy provides flexible control of security, and allows for convenient alteration of individual access rights. The mechanisms used for efficient implementation of the policy are described. Refinements were made to both the security mechanisms and the operations of the DBMS as the interaction of these two aspects was studied. Those refinements are discussed in some detail in this paper.