In the not-too-distant past, it was not uncommon for projects with functional safety requirements to be handled and implemented with no thought to cybersecurity issues. In recent years, however, it has become clear that this approach has risks for both domains – so standards for these disciplines state that functionally safe products must also be developed with cybersecurity risks in mind and vice versa. After a brief introduction to both domains, this article points out the challenges that developers face in functional safety and cybersecurity. Finally, a conclusion is drawn as to whether a harmonization of the development process for both domains can succeed at all.
The different focuses of the domains
The main focus of functional safety is to eliminate risks to life and limb as far as possible. Consequently, the requirements set out in the functional safety standards for the quality of the underlying development process intend to eliminate systematic errors in development as far as possible. Functional safety also focuses on qualitative and quantitative hardware design to minimize the risk of random hardware errors.
In cybersecurity, the focus is on product assets that are worth protecting, i.e., properties or content that relate to confidentiality, integrity and availability. To minimize risks in relation to these criteria, the standards both for cybersecurity and for functional safety set out requirements for the development process and also for the environment in which development takes place (e.g., personnel, computers, tools).
Harmonization of requirements
Given the many similarities in the standards for functional safety and cybersecurity, it obviously makes sense to harmonize the requirements for the two domains. One basic idea, for example, is a constructive approach to risk minimization, represented by the Security by Design and Safety by Design concepts. Rather than testing for errors and vulnerabilities at the end of the development phase, these two approaches bring functional safety and cybersecurity into concepts, design and architecture right from the start, avoiding errors from the outset. Another common feature is the fundamental requirement for a development process that ensures high-quality development results and work products.
Challenges of harmonization
In view of the different focuses of the two areas, there are some challenges to harmonizing their requirements. The first major task is to standardize the language used and to establish a common glossary, as there are lots of key terms common to both subject areas but some of those terms mean slightly different things in each area. The second challenge is the different level of detail of the requirements set out in the standards, which comes from their differing focuses. Thirdly, it is to be expected that designing and adapting requirements to the respective product- and project-specific requirements (tailoring) will increase complexity. In order to achieve “good” harmonized results that stand up to audits and assessments, experts from the different domains will have to intensively exchange information more than once.
Conclusion
Harmonizing the requirements set out in functional safety and cybersecurity norms and standards is an obvious step. Despite the difficulties, harmonization seems possible and also sensible, particularly as it would likely reduce the additional expenses that have inevitably arisen in the course of separate developments to date.
