  We introduce a semantic approach to the study of logics for access control
and dependency analysis, based on Game Semantics. We use a variant of AJM games
with explicit justification (but without pointers). Based on this, we give a
simple and intuitive model of the information flow constraints underlying
access control. This is used to give strikingly simple proofs of
\emph{non-interference theorems} in robust, semantic versions.
