Process Algebra and Information Flow

Process Algebra and Information Flow

Controlling information flows through a system is the fundamental issue in information security. It turns out that making precise the notion of information flow, and in particular the absence of information flow, is a remarkably subtle question. Many formalizations have been proposed, many inspired by the seminal ideas of Goguen and Meseguer with their notion of non-interference. Even now the s...

Probabilistic Information Flow in a Process Algebra

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 analysis of probabilistic systems and a notion of probabilistic bisimulation in order to define classical security properties, such as nondeterministic noninterference (NNI) and nondeducibility on comp...

Information Flow Analysis in a Discrete-Time Process Algebra

Some of the non interference properties studied in [4, 6, 18] for information flow analysis in computer systems, notably BNDC , are reformulated here in a realtime setting. This is done by enhancing the Security Process Algebra of [6, 10] with some extra constructs to model real-time systems (in a discrete time setting); and then by studying the natural extensions of those properties in this en...

Algebra for Quantitative Information Flow

A core property of program semantics is that local reasoning about program fragments remains sound even when the fragments are executed within a larger system. Mathematically this property corresponds to monotonicity of refinement : if A refines B then C(A) refines C(B) for any (valid) context defined by C(·). In other work we have studied a refines order for information flow in programs where ...

Probabilistic Process Algebra Probabilistic Process Algebra