RBAC lends itself to enforcing the separation-of-duty (SoD) principle. Recall that the goal of SoD is to guard against internal fraud and errors by limiting the powers of individuals. As a result, accountability becomes automatically built in the governing policy of an enterprise. We refer to this fact as autonomous accountability. The classical example expressing assurance in accountability based on SoD is the rule that prohibits auditors for auditing themselves. An auditor must be designated to perform audits on actions of other individuals. Auditing oneself yields a conflict of interest in which the individual is confronted with two semantically exclusive interests. The first is the requirement for impartiality, while the second is the natural bias that one may exhibit toward oneself.

Contrary to the potential for singlehandedly perpetrating fraud when sufficient powers are assigned to individuals, SoD is achieved by disseminating computing tasks along with associated permissions among multiple individuals. This is usually accomplished by first breaking a business process that presents a conflict of interest when viewed as a single set of transactions into its basic tasks that are free of conflict of interest. Once independent subtasks are identified, separate individuals are then authorized to perform each subtask. For instance, a role that evaluates a procurement process in an organization and one that authorizes payment represent a conflict of interest. An SoD policy that may remedy the potential for fraud in this case would assign different individuals to each of these...