Security aspects in functional safety analysis

A security level of distributed control and protection system may have a significant impact on the results of functional safety analysis. However, the issue of integrating the safety and security aspects is difficult and usually is neglected during the functional safety analysis. This article presents a method of functional safety analysis which takes into consideration a concept of integrating these two aspects. It is based on proposed classification of communication channels used in the computer system / network and the scope of such system distribution. The functional safety analysis is to be performed at every stage of system lifecycle, but one of the most important parts is defining required safety functions and determining the safety integrity level for them. The integration concept might be taken into account at this stage. The basis of a method proposed is the assumption that the security level is considered as a risk parameter in graphs of functional safety analyses.