  For the formal verification of a network security policy, it is crucial to
express the verification goals. These formal goals, called security invariants,
should be easy to express for the end user. Focusing on access control and
information flow security strategies, this work discovers and proves universal
insights about security invariants. This enables secure and convenient
auto-completion of host attribute configurations. We demonstrate our results in
a civil aviation scenario. All results are machine-verified with the
Isabelle/HOL theorem prover.
