CLARISSA

CLARISSA Tools consists of: (i) Assurance and Safety Case Environment (ASCE) which is the most widely adopted commercial software for the creation and management of safety and security assurance cases, and (ii) a goal-directed top-down solver for Constraints Answer Set Programs s(CASP) for reasoning about assurance cases using an enhanced Prolog engine.

ASCE has full support of Assurance 2.0 framework and enforces the methodology while it also facilitates systematic creation of Assurance 2.0 cases. The tool leverages theories, ensures the validity and soundness of the logical arguments with justifications while enabling active search for defeater and either sustaining or refuting them. Libraries of theories and defeaters are maintained as active repository of knowledge and known vulnerabilities. ASCE performs structural analysis to ensure their correct and complete construction while automatically analyzing specific syntactic elements of assurance cases including adherence to notations, grammar/spell-checks within natural language descriptions. ASCE automatically converts the assurance case to an equivalent logic program to support systematically reasoning with the s(CASP) engine.

The s(CASP) engine reasons over the semantics or underlying meaning of the claims, arguments, and evidence presented in assurance cases which includes various properties of the assurance case such as consistency (i.e. absence of logical contradictions), indefeasibility (i.e. absence of defeaters) and completeness (i.e. state of encompassing all the requisite elements), etc. This demonstration shows several assurance cases created with the ASCE software and allows the user to run different semantic analysis queries using the s(CASP) engine.