Revisiting sequential composition in process calculi

International audienceThe article reviews the various ways sequential composition is defined in traditional process calculi, and shows that such definitions are not optimal, thus limiting the dissemination of concurrency theory ideas among computer scientists. An alternative approach is proposed, based on a symmetric binary operator and write-many variables. This approach, which generalizes traditional process calculi, has been used to define the new LNT language implemented in the CADP toolbox. Feedback gained from university lectures and real-life case studies shows a high acceptance by computer-science students and industry engineers

Comparative Study of Eight Formal Specifications of the Message Authenticator Algorithm

The Message Authenticator Algorithm (MAA) is one of the first cryptographic functions for computing a Message Authentication Code. Between 1987 and 2001, the MAA was adopted in international standards (ISO 8730 and ISO 8731-2) to ensure the authenticity and integrity of banking transactions. In 1990 and 1991, three formal, yet non-executable, specifications of the MAA (in VDM, Z, and LOTOS) were developed at NPL. Since then, five formal executable specifications of the MAA (in LOTOS, LNT, and term rewrite systems) have been designed at INRIA Grenoble. This article provides an overview of the MAA and compares its formal specifications with respect to common-sense criteria, such as conciseness, readability, and efficiency of code generation.Comment: In Proceedings MARS/VPT 2018, arXiv:1803.0866

Formal Specification and Verification of Fully Asynchronous Implementations of the Data Encryption Standard

This paper presents two formal models of the Data Encryption Standard (DES), a first using the international standard LOTOS, and a second using the more recent process calculus LNT. Both models encode the DES in the style of asynchronous circuits, i.e., the data-flow blocks of the DES algorithm are represented by processes communicating via rendezvous. To ensure correctness of the models, several techniques have been applied, including model checking, equivalence checking, and comparing the results produced by a prototype automatically generated from the formal model with those of existing implementations of the DES. The complete code of the models is provided as appendices and also available on the website of the CADP verification toolbox.Comment: In Proceedings MARS 2015, arXiv:1511.0252