Covert timing channel analysis in MLS real-time systems /by Joon Son.

Mathematical analysis of possible covert timing channels is a requirement for certification of high assurance Multi-Level Secure (MLS) systems. In this dissertation, we present a mathematical approach for analysis of covert timing channels in MLS real-time systems. This approach includes an analytical model which can specify the types of real-time tasks running, the real-time scheduling algorithm in use, and real-time constraints imposed on task executions. Using this analytical real-time system model, we characterize timing vulnerabilities present in real-time systems, present a methodology for measuring covert timing channel capacity, and devise countermeasures to remove or mitigate the impact of covert timing channels. Finally, we present a precise mathematical model for evaluating how performance overhead/delays of real-time systems vary with respect to the different degrees of security measures being applied.Thesis (Ph. D., Computer Science)--University of Idaho, May 2008