  Our lives become increasingly dependent on safety- and security-critical
systems, so formal techniques are advocated for engineering such systems. One
of such techniques is validation obligations that enable formalizing
requirements early in development to ensure their correctness. Furthermore,
validation obligations help hold requirements consistent in an evolving model
and create assurances about the model's completeness. Although initially
proposed for safety properties, this paper shows how the technique of
validation obligations enables us to also reason about security concerns
through an example from the medical domain.
