Assurance Based Development of Critical Systems

Assurance based development (ABD) is the synergistic construction of a critical computing system and an assurance case that sets out the dependability claims for the system and argues that the available evidence justifies those claims. Co-developing the system and its assurance case helps software developers to make technology choices that address the specific dependability goal of each component. This approach gives developers: (1) confidence that the technologies selected will support the system´s dependability goal and (2) flexibility to deploy expensive technology, such as formal verification, only on components whose assurance needs demand it. ABD simplifies the detection - and thereby avoidance - of potential assurance difficulties as they arise, rather than after development is complete. In this paper, we present ABD together with a case study of its use.