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A Uniform Type Structure for Secure Information Flow
, 2002
"... The \picalculus is a formalism of computing in which we can compositionally represent dynamics of major programming constructs by decomposing them into a single communication primitive, the name passing. This work reports our experience in using a linear/affine typed \picalculus for the analysis a ..."
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Cited by 76 (11 self)
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The \picalculus is a formalism of computing in which we can compositionally represent dynamics of major programming constructs by decomposing them into a single communication primitive, the name passing. This work reports our experience in using a linear/affine typed \picalculus for the analysis and development of type systems of programming languages, focussing on secure information flow analysis. After presenting a basic typed calculus for secrecy, we demonstrate its usage by a sound embedding of the dependency core calculus (DCC) and by the development of a novel type discipline for imperative programs which extends both a secure multithreaded imperative language by Smith and Volpano and (a callbyvalue version of) DCC. In each case, the embedding gives a simple proof of noninterference.
Secure Information Flow as Typed Process Behaviour
, 2000
"... We propose a new type discipline for the calculus in which secure information ow is guaranteed by static type checking. Secrecy levels are assigned to channels and are controlled by subtyping. A behavioural notion of types capturing causality of actions plays an essential role for ensuring safe ..."
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Cited by 52 (0 self)
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We propose a new type discipline for the calculus in which secure information ow is guaranteed by static type checking. Secrecy levels are assigned to channels and are controlled by subtyping. A behavioural notion of types capturing causality of actions plays an essential role for ensuring safe information ow in diverse interactive behaviours, making the calculus powerful enough to embed known calculi for typebased security. The paper introduces the core part of the calculus, presents its basic syntactic properties, and illustrates its use as a tool for programming language analysis by a sound embedding of a secure multithreaded imperative calculus of Volpano and Smith. The embedding leads to a practically meaningful extension of their original type discipline.
Composing Processes
, 1996
"... We present a theory of types for concurrency based on a simple notion of typed algebras, and discuss its applications. The basic idea is to determine a partial algebra of processes by a partial algebra of types, thus controlling process composability, just as types in a typed applicative structure [ ..."
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Cited by 28 (4 self)
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We present a theory of types for concurrency based on a simple notion of typed algebras, and discuss its applications. The basic idea is to determine a partial algebra of processes by a partial algebra of types, thus controlling process composability, just as types in a typed applicative structure [25] determine composability of elements of the underlying applicative structure. A class of typed algebras with a simple operator for process composition are introduced, which are shown to encompass a wide range of type disciplines for processes, placing extant theories such as Milner's sorting [22] and Lafont's typed nets [20] on a uniform technical footing, suggesting generalisations, and offering a secure basis for integration. We also prove that the class of typable operations in the underlying partial algebras is completely characterised by a certain modularity principle in process composition, which gives us the basic understanding on the nature of the type disciplines representable in...
Behavioural Subtyping in Name Passing Synchronisation Trees
, 1999
"... . We present a general theory of behavioural subtyping for name passing interactive behaviours using early namepassing synchronisation trees. In this theory types are collections of name passing synchronisation trees organised by typed variants of processtheoretic operations, and a simple behaviour ..."
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Cited by 1 (0 self)
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. We present a general theory of behavioural subtyping for name passing interactive behaviours using early namepassing synchronisation trees. In this theory types are collections of name passing synchronisation trees organised by typed variants of processtheoretic operations, and a simple behavioural notion of subtyping specifies when one type denotes more constrained behaviours than another, offering a semantic basis for diverse instances of subtyping in sequential and concurrent computation through their representation in name passing. The robustness of the notion is shown by a few equivalent characterisations, including the one based on the subset inclusion with respect to inhabitants of types and another concerning a basic substitutability property. As an application, we show how the subtyping in the calculus with constant data domains is soundly embeddable into the present theory, illuminating the functional notion of subtyping from a behavioural viewpoint. 1. Introduction The ...
On Behavioural Interpretation of Types in Name Passing Calculi (extended )
"... We introduce a theory of behavioural types as a semantic foundation of typed ßcalculi. In this theory, a type is a set of behaviours, represented by early name passing synchronisation trees, which conform to a certain behavioural constraint. Operations on typed processes are derived from typed vari ..."
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Cited by 1 (1 self)
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We introduce a theory of behavioural types as a semantic foundation of typed ßcalculi. In this theory, a type is a set of behaviours, represented by early name passing synchronisation trees, which conform to a certain behavioural constraint. Operations on typed processes are derived from typed variants of wellknown processtheoretic operations for mobile processes, and each model of typed ßcalculi in a typed universe induces a compositional theory of typed bisimilarities. The construction is simple and intuitive, yet offers a rich class of typed universes of name passing interactive behaviours, which contain, among others, models of known typed ßcalculi and universes of game semantics. As a simple but nontrivial application, we show how the sorting by Milner can be given a sound model in a basic universe of types. The soundness states not only that the interpretation is sound in the standard sense, but also that the untyped interactive behaviour of typed terms is justifiable on t...
Processes and Games
, 2003
"... A general theory of computing is important, if we wish to have a common mathematical footing based on which diverse scienti c and engineering eorts in computing are uniformly understood and integrated. A quest for such a general theory may take dierent paths. As a case for one of the possible paths ..."
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A general theory of computing is important, if we wish to have a common mathematical footing based on which diverse scienti c and engineering eorts in computing are uniformly understood and integrated. A quest for such a general theory may take dierent paths. As a case for one of the possible paths towards a general theory, this paper establishes a precise connection between a gamebased model of sequential functions by Hyland and Ong on the one hand, and a typed version of the calculus on the other. This connection has been instrumental in our recent eorts to use the calculus as a basic mathematical tool for representing diverse classes of behaviours, even though the exact form of the correspondence has not been presented in a published form. By redeeming this correspondence we try to make explicit a convergence of ideas and structures between two distinct threads of Theoretical Computer Science. This convergence indicates a methodology for organising our understanding on computation and that methodology, we argue, suggests one of the promising paths to a general theory.
Processes, Types and Information Flow
"... . We develop a behavioural theory of secure information ow using a typed calculus as a metalanguage, and show its applicability to the analysis and reasoning of secrecy concerns in programming languages. The key technical novelty is a new typed bisimilarity which accurately captures the ow of infor ..."
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. We develop a behavioural theory of secure information ow using a typed calculus as a metalanguage, and show its applicability to the analysis and reasoning of secrecy concerns in programming languages. The key technical novelty is a new typed bisimilarity which accurately captures the ow of information among processes based on a given type structure. A behavioural theory of secrecy is introduced, for which we establish fundamental results such as noninterference. The use of the general theory is shown by formulating and establishing a compositional soundness property for a generalisation of the multithreaded imperative calculus by VolpanoSmith [32]; and by introducing sound typing rules for mutable and immutable references and local declaration based on the analysis using the typed process representation. The soundness of the new typing rules is again established using the general theory. 1 Introduction This paper presents a basic principle for analysing and reasoning about s...