Analyzing and Securing Social Networks

233Access Control forSocial Networks

In contrast, an admin prohibition can be represented as a tuple (s,t,o,p), which implies that user s

(supervisor) is authorized to specify ltering policies for the privilege p applying to the target user t

and to object o. Differently from previous authorizations, admin prohibitions cannot be represented

as properties in that they do not represent a binary relationship. For that reason, we decide to model

admin prohibitions as an OWL class Prohibition. This enables us to specify all the components

of the prohibition as class properties. More precisely, given an admin prohibition (s,t,o,p), we can

model the authorized supervisor to have an object property Supervisor between the Prohibition

and Person cl ...