Formal description of HOrBAC model

Abstract Companies' information systems are regularly exposed to internal attacks perpetrated by users who have been granted access to the system. Discretionary, mandatory, role-based and organization-based access control models do not guarantee optimal protection against these attacks because these models trust in users. Therefore, they are unable to protect the system against attacks carried out by authenticated users, especially the super user who can carry out any type of internal attack on information system's data. The objective of this paper is to propose a model that excludes any trust in users. To do so, our model extends the OrBAC (Organization Based Access Control) model by integrating two concepts: the organizational hierarchy and the redundant authentication. The model thus implemented offers a hierarchical and redundant access control to data and processing in an information system based on zero trust in users.