  The theory of noninterference supports the analysis of information leakage
and the execution of secure computations in multi-level security systems.
Classical equivalence-based approaches to noninterference mainly rely on weak
bisimulation semantics. We show that this approach is not sufficient to
identify potential covert channels in the presence of reversible computations.
As illustrated via a database management system example, the activation of
backward computations may trigger information flows that are not observable
when proceeding in the standard forward direction. To capture the effects of
back-and-forth computations, it is necessary to switch to a more expressive
semantics, which has been proven to be branching bisimilarity in a previous
work by De Nicola, Montanari, and Vaandrager. In this paper we investigate a
taxonomy of noninterference properties based on branching bisimilarity along
with their preservation and compositionality features, then we compare it with
the taxonomy of Focardi and Gorrieri based on weak bisimilarity.
