  In this work, we propose a compositional framework for the verification of
approximate initial-state opacity for networks of discrete-time switched
systems. The proposed approach is based on a notion of approximate
initial-state opacity-preserving simulation functions (InitSOPSFs), which
characterize how close concrete networks and their finite abstractions are in
terms of the satisfaction of approximate initial state opacity. We show that
such InitSOPSFs can be obtained compositionally by assuming some small-gain
type conditions and composing so-called local InitSOPSFs constructed for each
subsystem separately. Additionally, for switched systems satisfying certain
stability properties, we provide an approach to construct their finite
abstractions together with the corresponding local InitSOPSFs. Finally, the
effectiveness of our results is illustrated through an example.
