Non-Interference Through Determinism

The standard approach to the specification of a secure system is to present a (usually state-hased) abstract security model separately from the specification of the system's functional n:quirements, and establishing a correspondence between the two specifications. This complex treatment has resulted in development methods distinct from those usually advocated for general applications. We provide a novel and intellectually satisfying formulation of security propel1ies in a process algebraic framework. and show that these are preserved under refinement. We relate the results to a more familiar state-based (Z) specification methodology. There are efficient algorithms for verifying our security properties using model checking.