Rewriting-Based Access Control Policies

In this paper we propose a formalization of access control policies based on term rewriting. The state of the system to which policies are enforced is represented as an algebraic term, what allows to model many aspects of the policy environment. Policies are represented as sets of rewrite rules, whose evaluation produces deterministic authorization decisions. We discuss the relation between properties of \trs and those important for access control, and the impact of composing policies to these properties

ARC: An Educational Project on Automated Reasoning in the Class

International audienceThe international Erasmus+ European Project: "ARC-Automated Reasoning in the Class", running from 2019 to 2022 is a partnership of universities from Austria, France, Germany, Hungary, and Romania, and has the purpose of developing advanced material for teaching subjects related to Computational Logic by using Automated Reasoning. The material includes a comprehensive textbook treating the necessary theoretical background (selected topics in Mathematical Logic), but mostly the practical methods from Automated Theorem Proving, as well as the description of the basic programming paradigms and the associated languages, in relation to their logical aspects. Furthermore, we address the most important applications, like program verification and testing, semantic representation of information, algorithm synthesis, etc. One of the main goals of the approach is to improve the logical background of the software professionals in order to motivate them to use formal methods for certification of complex systems and thus to avoid costly failures

Mechanical Verification of an Ideal Incremental ABR Conformance Algorithm

Colloque avec actes et comité de lecture. internationale.International audienceNous prouvons la correction d'un algorithme de conformance ABR pour ATM

Mechanical Verification of an Ideal Incremental ABR Conformance Algorithm

The Available Bit Rate protocol (ABR) for ATM networks is well-adapted to data trac by providing minimum rate guarantees and low cell loss to the ABR source end system. An ABR conformance algorithm for controlling the source rates through an interface has been defined by ATM Forum and a more ecient version of it has been designed in [14]. We present in this work the first complete mechanical verification of the equivalence between these two algorithms. The proof is involved and has been supported by the PVS theorem-prover. It has required many lemmas, case analysis and induction reasoning for the manipulation of unbounded scheduling lists. Some ABR conformance protocols have been verified in previous works. However these protocols are approximations of the one we consider here. For instance, the algorithms mechanically proved in [11] and [6] consider scheduling lists with only two elements