李彤《软件工程》教学课件ch24.pptVIP

Hazard analysis Hazard analysis involves identifying hazards and their root causes. There should be clear traceability from identified hazards through their analysis to the actions taken during the process to ensure that these hazards have been covered. A hazard log may be used to track hazards throughout the process. Hazard log entry Run-time safety checking During program execution, safety checks can be incorporated as assertions to check that the program is executing within a safe operating ‘envelope’. Assertions can be included as comments (or using an assert statement in some languages). Code can be generated automatically to check these assertions. Insulin administration with assertions Security assessment Security assessment has something in common with safety assessment. It is intended to demonstrate that the system cannot enter some state (an unsafe or an insecure state) rather than to demonstrate that the system can do something. However, there are differences Safety problems are accidental; security problems are deliberate; Security problems are more generic - many systems suffer from the same problems; Safety problems are mostly related to the application domain Security validation Experience-based validation The system is reviewed and analysed against the types of attack that are known to the validation team. Tool-based validation Various security tools such as password checkers are used to analyse the system in operation. Tiger teams A team is established whose goal is to breach the security of the system by simulating attacks on the system. Formal verification The system is verified against a formal security specification. Security checklist Safety and dependability cases Safety and dependability cases are structured documents that set out detailed arguments and evidence that a required level of safety or dependability has been achieved. They are normally required by regulators before a system can be certified for operational use. The system safety ca