The University of SydneyPage 3Recap of Week 4 –Issues in Bell-La PadulaModel–Covert channel information flow is not protected.–A covert channel is a way for an entity to receive information in an unauthorized manner. –It is an information flow that is not controlled by a security mechanism or the mechanism has been successfully compromised.–The flow occurs via system resources (file attributes, flags, clocks, etc.) that were not intended as communication channels. –A covert storage channel uses an attribute of the shared resource. A covert timing channel uses a temporal or ordering relationship among accesses to a shared resource.