At present I teach a small course (Four two hour lectures at the Masters level) on Logical Methods in Security, though the title Formal Methods in Security might be more apt. It covers briefly the following topics (with associated logical methods):
Digital Rights Management and Policy Enforcement (general formalisation, modal logic, enforcement via automata)
Proof-carrying code and proof-carrying authentication (proof theory, logical systems, Curry-Howard Isomorphism, verification)
Access Control (non-classical logics, proof theory)
Stack Inspection (programming language semantics, contextual equivalence, bisimulation)
Naturally, the course has multiple goals, where one of them is attracting potential graduate students.
In the coming years the course may be expanded to a regular course, which will need more content. Given that the background of people here is quite different from mine, I would like to know what content you would include in such a course.