Correctness-by-Construction: An Overview of the CorC Ecosystem

Correctness-by-Construction (CbC) is an incremental software development technique in the field of formal methods to create functionally correct programs guided by a specification. In contrast to post-hoc verification, where the specification and verification take part after implementing a program, with CbC the specification is defined first, and then the program is successively created using a small set of refinement rules that define side conditions preserving the correctness of the program. This specification-first, refinement-based approach as pursued by CbC has the advantage that errors are likely to be detected earlier in the design process and can be tracked more easily. Even though the idea of CbC emerged over 40 years ago, CbC is not widespread and is mostly used to create small algorithms.We believe in the idea of CbC and envision a scaled CbC approach that contributes to solving problems of modern software verification. In this short paper, we give an overview of our research regarding CbC in four different lines of research. For all of them, we provide tool support for building the CorC ecosystem that even further enables CbC-based development for different fields of application and size of software systems. Furthermore, we give an outlook on future work that extends on our concepts for CbC.