Preventing Inference to an Attribute Set due to Functional Dependencies

This paper describes the concept of preventing some users from accessing an attribute set while an access to individual attributes of the set may be permitted. It seems that this kind of access control has not yet been provided in current relational database systems[1](such as SQL/DS, INGRES)or studied in a Multilevel Relational Data Model proposed by Denning[2]. Although an access to the attribute set is protected, an inference to the attribute set may possibly be done by using knowledge of functional dependencies in the database. To protect such an inference, any accessto other attribute sets needed to infer the attribute set must also be prevented. This paper applies the Chase Algorithm[3] to examine whether preventing access to those attribute sets is sufficient to protect inference to the prevented attribute set.