Controller Synthesis for Hyperproperties

Abstract: We investigate the problem of controller synthesis for hyperproperties specified in the temporal logic HyperLTL. Hyperproperties are system properties that relate multiple execution traces. Hyperproperties can elegantly express information-flow policies like noninterference and observational determinism. The controller synthesis problem is to automatically design a controller for a plant that ensures satisfaction of a given specification in the presence of the environment or adversarial actions. We show that the controller synthesis problem is decidable for HyperLTL specifications and finite-state plants. We provide a rigorous complexity analysis for different fragments of HyperLTL and different system types: tree-shaped, acyclic, and general graphs.