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3.5. Safety and Network Security
1
st
and 2
nd
generation Safety Systems were not designed to reside on a networked plant. For the most part,
these systems allowed some communication interface or gateway but were not intended for integration. In
general, therefore, 1
st
and 2
nd
generation Safety System are not equipped to counter security threats like those
the industry has experienced in recent years.
A brief analysis of the definitions will clearly show that Safety issues are random in nature and statistical
analysis is possible security intentional in nature and statistical analysis will not measure performance.
The authors concur with industry standards and experts in the field. Network security may affect system
performance and the safety of the installation. A system can’t be safe without it being secure.
3.6. Design Best Practices and V-Model
As indicated earlier, industry standards in Functional Safety introduced the concept of Functional Safety
Management System (FSMS) which includes a series of steps in the design, documentation and testing of the
system, and should include Network Security as well.
Today product development or design organizations responsible for releasing COTS products (hardware and
software) intended for safety applications use design best practices as the V-Model (Figure 3) and are
evaluated by a third party organization (i.e. TUV) and their FSMS is approved prior to the assessment of their
products.