Modelling information routing with noninterference

To achieve the highest levels of assurance, MILS architectures need to be formally analysed. A key challenge is to reason about the interaction between the software applications running on top of MILS core components, such as the separation kernel. In this paper, we extend Rushby's model of noninterference with explicit information units and domain programs. These extensions enable the reasoning at an abstract level about systems built on top of noninterference. As an illustration of our approach, we formally model and analyse an example inspired by the GWV Firewall. <br/

Using SMT for solving fragments of parameterised Boolean equation systems

Fixpoint logics such as parameterised Boolean equation systems (PBESs) provide a unifying framework in which a number of practical decision problems can be encoded. Efficient evaluation methods (solving methods in the terminology of PBESs) are needed to solve the encoded decision problems. We present a sound pseudo-decision procedure that uses SMT solvers for solving conjunctive and disjunctive PBESs. These are important fragments, allowing to encode typical verification problems and planning problems. Our experiments, conducted with a prototype implementation, show that the new solving procedure is complementary to existing techniques for solving PBESs

Using SMT for solving fragments of parameterised Boolean equation systems

Fixpoint logics such as parameterised Boolean equation systems (PBESs) provide a unifying framework in which a number of practical decision problems can be encoded. Efficient evaluation methods (solving methods in the terminology of PBESs) are needed to solve the encoded decision problems. We present a sound pseudo-decision procedure that uses SMT solvers for solving conjunctive and disjunctive PBESs. These are important fragments, allowing to encode typical verification problems and planning problems. Our experiments, conducted with a prototype implementation, show that the new solving procedure is complementary to existing techniques for solving PBESs