A framework for determining the sufficiency of software safety assurance

In this paper we present a framework for ensuring software suppliers provide the necessary information about their software in order to support an overall platform safety case. The framework has been developed particularly for use on defence projects utilising a range of both bespoke and previously developed software. The framework aims to provide detailed guidance on what is expected from the software supplier (to avoid ambiguity, inconsistency and uncertainty), but not to unnecessarily constrain the supplier by detailing how that should be achieved (to facilitate the use of previously developed software and a wide supplier base). The framework defines a set of five core software safety assurance principles. These principles must be shown to be addressed for all software that may contribute to hazards of the platform. The framework also defines the criteria by which the sufficiency of the evidence provided by the supplier against these principles is determined.