The article focuses on the continuous improvement of Ate-lier B's automatic proof capabilities since its industrialisation in the 90s. The evolution of Atelier B addressed challenges in proof obligations generation and optimisation, adapting to new languages like Event-B and incorporating newer formats for easier analysis and third-party prover connections. Significant developments include enhancing the proof system to handle complex proof obligations efficiently and integrating external provers for improved proof capabilities. The article also showcases B's industrial applications in critical sectors, emphasising the method's importance in safety-critical software development and the ongoing efforts to facilitate proof activities and integrate AI for better proof automation.

The distribution of safety functions along the tracks requires the networking of the ECUs (Electronic Control Unit is an embedded system that controls one or more electrical systems or subsystems) that support them, to facilitate their operation and maintenance. The latter enables logs to be sent, commands to be received and sent that will lead to a state change of one of the connected equipment, and the ECU application software to be updated. All these activities are naturally subject to targeted attacks aimed at reducing the availability of the equipment or disrupting its operational safety to the point of creating accidents. This article presents an innovative approach partitioning security and safety on two different computers. One computer connected to the network ensures security and is regularly updated according to known threats. The other computer ensures safety and communicates only through a secure filter. Each computer embeds technological elements that have been specified, implemented and proven with 2 different formal methods.KeywordsFormal methodsCybersecuritySafety

The CLEARSY Safety Platform (CSSP) is both a hardware and software platform aimed at developing safety critical applications. A smart combination of hardware features (double processor) and formal method (B method and code generators) was used to produce a SIL4-ready platform where safety principles are built-in. A first version, SK0, was released for education purpose with a restricted application template. An industry-strength version, CS0, was then released, providing more degrees of freedom at the cost of a more tricky development and engineering process. This article presents the new CS0 modelling paradigm, lists the conditions to be verified by the system developed, and briefly introduces a first application, software only: a safety flasher.

Industrial applications involving formal methods are still exceptions to the general rule. Lack of understanding, employees without proper education, difficulty to integrate existing development cycles, no explicit requirement from the market, etc. are explanations often heard for not being more formal. This article reports some experience about a game changer that is going to seamlessly integrate formal methods into safety critical systems engineering.

The CLEARSY Safety Platform (CSSP) was designed to ease the development of safety critical systems and to reduce the overall costs (development, deployment, and certification) under the pressure of the worldwide market. A smart combination of hardware features (double processor) and formal method (B method and code generators) was used to produce a SIL4-ready platform where safety principles are built-in and cannot be altered by the developer. Summarizing a 5-year return of experience in the effective application in the railways, this article explains how this approach is a game-changer and tries to anticipate the future of this platform for safety critical systems. In particular, the education of future engineers and the seamless integration in existing engineering processes with the support of Domain Specific Languages are key topics for a successful deployment in other domains. DSL like Robosim to program mobile robots and relay circuits to design railway signalling systems are connected to the platform.