Bounding messages for free in security protocols - extension to various security properties

International audienceWhile the verification of security protocols has been proved to be undecidable in general, several approaches use simplifying hypotheses in order to obtain decidability for interesting subclasses. Amongst the most common is type abstraction, i.e. considering only well-typed runs of the protocol, therefore bounding message length. In this paper, we show how to get message boundedness “for free” under a reasonable (syntactic) assumption on protocols, in order to verify a variety of interesting security properties including secrecy and several authentication properties. This enables us to improve existing decidability results by restricting the search space for attacks

Typing and Compositionality for Security Protocols::A Generalization to the Geometric Fragment

We integrate, and improve upon, prior relative soundness results of two kinds. The first kind are typing results showing that any security protocol that fulfils a number of sufficient conditions has an attack if it has a well-typed attack. The second kind considers the parallel composition of protocols, showing that when running two protocols in parallel allows for an attack, then at least one of the protocols has an attack in isolation. The most important generalization over previous work is the support for all security properties of the geometric fragment