Development of secured systems by mixing programs, specifications and proofs in an object-oriented programming environment: a case study within the FoCaLiZe environment

FoCaLiZe is an object-oriented programming environment that combines specifications, programs and proofs in the same language. This paper describes how its features can be used to formally express specifications and to develop by stepwise refinement the design and implementation of secured systems, while proving that the implementation meets its specification or design requirements. We thus obtain a modular implementation of a generic framework for the definition of security policies together with certified enforcement mechanism for these policies.