This paper presents the modal interface theory, a unification of interface automata and modal specifications, two radically dissimilar models for interface theories. Interface automata is a game-based model, which allows the designer to express assum

This paper presents a unification of interface automata and modal specifications, two radically dissimilar models for interface theories. Interface automata is a game-based model, which allows to make assumptions on the environment and propose an optimistic view for composition : two components can be composed if there is an environment where they can work together. Modal specification is a language theoretic account of a fragment of the modal mu-calculus logic that is more complete but which does not allow to distinguish between the environment and the component. Partial unifications of these two frameworks have been explored recently. A first attempt by Larsen et al. considers modal interfaces, an extension of modal specifications that deals with compatibility issues in the composition operator. However, this composition operator is incorrect. A second attempt by Raclet et al. gives a different perspective, and emphasises on conjunction and residuation of modal specifications, including when interfaces have dissimilar alphabets, but disregards interface compatibility. The present paper contributes a thorougher unification of the two theories by correcting the modal interface composition operator presented in the paper by Larsen et al., drawing a complete picture of the modal interface algebra, and pushing even further the comparison between interface automata, modal automata and modal interfaces.

In order to increase their stealth, malware commonly use the self-modification property of programs. By doing so, programs can hide their real code so that it is difficult to define a signature for it. But then, what is the meaning of those programs: the obfuscated form, or the hidden one? Furthermore, from a computability perspective, it becomes hard to speak about the program since, its own code varies over time. To cope with these issues, we provide an operational semantics for self-modifying programs and we show that they can be constructively rewritten to a non-modifying program.