Temporal Logics for Hyperproperties

Two new logics for verification of hyperproperties are proposed. Hyperproperties characterize security policies, such as noninterference, as a property of sets of computation paths. Standard temporal logics such as LTL, CTL, and CTL* can refer only to a single path at a time, hence cannot express many hyperproperties of interest. The logics proposed here, HyperLTL and HyperCTL, add explicit and simultaneous quantification over multiple paths to LTL and to CTL. This kind of quantification enables expression of hyperproperties. A model checking algorithm for the proposed logics is given. For a fragment of HyperLTL, a prototype model checker has been implemented.