eMEDAC: Role-based Access Control Supporting Discretionary and Mandatory Features

In this paper, we present an enhanced use of RBAC features in articulating a security policy for access control in medical database systems. The main advantage of this implementation is that it supports both MAC and DAC features at the same time; a feature that has been proved to be necessary in healthcare environments. The eMEDAC security policy that results from the above implementation provides an enhanced redefinition of a number of mechanisms of the already known MEDAC security policy. The concept of hyper node hierarchies is proposed for deriving totally ordered security levels while preserving the role hierarchy levels required satisfying particular administration needs. Finally, a demonstration example is given based on the pilot implementation of the proposed security policy in a major Greek hospital. The advantages offered are related to the efficiency of access control, the flexibility and decentralisation of administration, and the storage savings.