The Bell-LaPadula Computer Security Model Represented as a Special Case of the Harrison-Ruzzo-Ullman Model

Specifically, suppose we have a BLP model which consists Currently most computer security models are classified among the tl:l~ types; access control, information flow, and non-interference. Within the realm of access control lies the classical Bell-LaPadula model. A BLP model consists of a set of subjects and objects, thr~e security level functions, and a discretionary access matrix together with a set of rules used to manipulate the current state of the model. Security in this model is dependent upon the satisfaction of the three properties: simple security, discretionary access, and the * property. An HRU model consists of an access matrix and a finite set of commands which act as matrix transformations. Here security is determined by looking for the existence of an access right in a specific cell of the matrix. We define a specific HRU model (called the Bobo model) and establish a correspondence between the Bobo commands and BLP rules, also between the Bobo and BLP states. Furthermore we observe that this correspondence is security preserving in the fact that a BLP access triple is secure if and only if that access is contained in a specific cell of the Bobo access matrix.