Making security type systems less ad hoc

We present a uniform, top-down design method for security type systems applied to a parallel while-language. The method takes the following route: from a notion of end-to-end security via a collection of stronger notions of anytime security targeting compositionality to a matching collection of type-system-like syntactic criteria. This method has emerged by distilling and unifying security type system results from the literature while formalizing them in a proof assistant. Unlike in our previous papers on this topic, here we focus entirely on high-level ideas instead of technical proof details

Making security type systems less ad hoc

We present a uniform, top-down design method for security type systems applied to a parallel while-language. The method takes the following route: from a notion of end-to-end security via a collection of stronger notions of anytime security targeting compositionality to a matching collection of type-system-like syntactic criteria. This method has emerged by distilling and unifying security type system results from the literature while formalizing them in a proof assistant. Unlike in our previous papers on this topic, here we focus entirely on high-level ideas instead of technical proof details

Formalizing probabilistic noninterference

We present an Isabelle formalization of probabilistic noninterference for a multi-threaded language with uniform scheduling. Unlike in previous settings from the literature, here probabilistic behavior comes from both the scheduler and the individual threads, making the language more realistic and the mathematics more challenging. We study resumption-based and trace-based notions of probabilistic noninterference and their relationship, and also discuss compositionality w.r.t. the language constructs and type-system-like syntactic criteria. The formalization uses recent development in the Isabelle probability theory library

Proving concurrent noninterference

We perform a formal analysis of compositionality techniques for proving possibilistic noninterference for a while language with parallel composition. We develop a uniform framework where we express a wide range of noninterference variants from the literature and compare them w.r.t. their contracts: the strength of the security properties they ensure weighed against the harshness of the syntactic conditions they enforce. This results in a simple implementable algorithm for proving that a program has a specific noninterference property, using only compositionality, which captures uniformly several security type-system results from the literature and suggests a further improved type system. All formalism and theorems have been mechanically verified in Isabelle/HOL

Formal verification of language-based concurrent noninterference

We perform a formal analysis of compositionality techniques for proving possibilistic noninterference for a while language with parallel composition. We develop a uniform framework where we express a wide range of noninterference variants from the literature and compare them w.r.t. their contracts: the strength of the security properties they ensure weighed against the harshness of the syntactic conditions they enforce. This results in a simple implementable algorithm for proving that a program has a specific noninterference property, using only compositionality, which captures uniformly several security type-system results from the literature and suggests a further improved type system. All formalism and theorems have been mechanically verified in Isabelle/HOL

Formal verification of language-based concurrent noninterference

We perform a formal analysis of compositionality techniques for proving possibilistic noninterference for a while language with parallel composition. We develop a uniform framework where we express a wide range of noninterference variants from the literature and compare them w.r.t. their contracts: the strength of the security properties they ensure weighed against the harshness of the syntactic conditions they enforce. This results in a simple implementable algorithm for proving that a program has a specific noninterference property, using only compositionality, which captures uniformly several security type-system results from the literature and suggests a further improved type system. All formalism and theorems have been mechanically verified in Isabelle/HOL