Abstract. We consider the problem of defining the information leakage in interactive systems where secrets and observables can alternate during the computation. We show that the information-theoretic approach which interprets such systems as (simple) noisy channels is no longer valid. However, the principle can be recovered if we consider channels of a more complicated kind, that in Information Theory are known as channels with memory and feedback. We show that there is a complete correspondence between interactive systems and such kind of channels. Furthermore, we show that the capacity of the channels associated to such systems is a continuous function of a pseudometric based on the Kantorovich metric.
Alvim, Andrés and Palamidessi REF study leakage and channel capacity of interactive systems where secrets and observables can alternate during the computation.
Quantitative Information Flow in Interactive Systems
JOURNAL OF COMPUTER SECURITY (2011)
Computer Science