A Security Model and Its Implementation

A new security model is proposed which allows the notions of confidentiality and integrity to be expressed in one coherent framework. Confidentiality is taken to be solely concerned with the observation of classified information, while separation of duty is employed as the technique for assuring the integrity of the security labels which are the basis of confidentiality. Discretionary access control is modelled by access control lists whose integrity is also provided by separation of duty controls. The specification of a simple system is given as an example of the techniques and methods for implementation are discussed. Great Britain.