MSR, Access Control, and the Most Powerful Attacker

Most systems designed for the verification of security protocols operated under the unproved assumption that an attack can only result from the combination of a fixed number of message transformations, which altogether constitute the capabilities of the so-called Dolev-Yao intruder. In this paper, we prove that the Dolev-Yao intruder can indeed emulate the actions of an arbitrary adversary. In order to do so, we extend MSR, a flexible specification framework for security protocols based on typed multiset rewriting, with a static check called access control and aimed at catching specification errors such as a principal trying to use a key that she is not entitled to access.