Temporal Context-Based Delegation

In this paper, we put forward a dynamic delegation model based on a temporal context. Delegation is the process of granting a specific authorization from a user to another user of the same system to carry out some functions on his behalf. Despite the importance of delegation, it is formalized in very little security policies because of its complexity. Indeed delegation provides resiliency and flexibility regarding the management procedure. Our goal consists of redefining delegation for OrBAC using temporal nonmonotonic description logic. OrBAC is an access control model; it provides the mean to specify contextual authorizations, which facilitates modeling delegation features such as temporary delegation, multiple delegation, revocation, etc. The description logic that we use for the re-formalization process is TDL delta epsilon. This logic gives the mean to specify nonmonotonic authorizations and a better representation of the temporal aspects specific to a given delegation. The motivation behind this new representation is to augment the expressivity of the new model to offer a better way to represent and to manage the delegation's characteristics.