Study of a fuzzy multilevel security relational data model

In this paper, a new fuzzy multilevel security data model based on polyinstantiation is put forward. By this model, some tuples with different security level are merged into a tuple with a security pattern which matches those tuples′ security level, and the user can access the resource if only this resource’s security pattern match the user's permits level. This model solves such problems as data redundancy and covert channel.