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Summary: Probabilistic Information Flow
in a Process Algebra
Alessandro Aldini
Universit`a di Bologna, Dipartimento di Scienze dell'Informazione,
Mura Anteo Zamboni 7, 40127 Bologna, Italy,
aldini@cs.unibo.it
http://www.cs.unibo.it/~aldini
Abstract. We present a process algebraic approach for extending to
the probabilistic setting the classical logical information flow analysis
of computer systems. In particular, we employ a calculus for the anal-
ysis of probabilistic systems and a notion of probabilistic bisimulation
in order to define classical security properties, such as nondeterministic
noninterference (NNI) and nondeducibility on compositions (NDC), in
the probabilistic setting. We show how to (i) extend the results known
for the nondeterministic case, (ii) analyse insecure nondeterministic be-
haviors, and (ii) reveal probabilistic covert channels which may be not
observable in the nondeterministic case. Finally, we show that the expres-
siveness of the calculus we adopt makes it possible to model concurrent
systems in order to derive also performance measures.
1 Introduction
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