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In the industry, blockchains are increasingly used as the backbone of product and process traceability. Blockchain-based traceability participates in the demonstration of product and/or process compliance with existing safety standards or quality criteria. In this perspective, services and applications built on top of blockchains are business-critical applications, because an intended failure or corruption of the system can lead to an important reputation loss regarding the products or the processes involved. The development of a blockchain-based business-critical application must be then conducted carefully, requiring a thorough justification of its dependability and security. To this end, this paper encourages an engineering perspective rooted in well-understood tools and concepts borrowed from the engineering of safety-critical systems. Concretely, we use a justification framework, called CAE (Claim, Argument, Evidence), by following an approach based on assurance cases, in order to provide convincing arguments that a business-critical blockchain-based application is dependable and secure. The application of this approach is sketched with a case study based on the blockchain HYPERLEDGER FABRIC., 8 pages, 6 figures, The Third IEEE International Conference on Blockchain Computing and Applications (BCCA 2021)

International audience; This paper presents an approach to assess the effects of common cause failures (CCF) on dependability of digital systems. Independent failures of system components and partial or lethal shocks are considered in a global CCF model, the Atwood model. The Coloured Petri nets (CPN) are used to modelize the digital system and the common cause failures. Based on the CPN, the parameters of Atwood model are estimated analytically and by Monte-Carlo simulation. Thereafter, the Atwood model of CCF is modified in order to represent the dominant failures propagation on some system components in the case of partial shocks. The assessment of system dependability, in the presence of CCF failures, becomes possible. This approach is applied to a representative instrumentation and control system of a nuclear power plant. The system is large with a high level of redundancy.

The purpose of this study is the representation of Common Cause Failures (CCF) in large digital systems. The system under study is representative of a control system of a nuclear plant. The model for CCF is the generalized Atwood model. It can represent independent failures, CCF non-lethal for some system elements and CCF lethal to all. The Atwood model was modified to "direct" non-lethal DCC on certain parts of the system and take into account the different possible origins of DCC. Maintenance and repairs are taken into account in the model that is thus dynamic. The main evaluation results are probabilistic, the considered indicator is the probability of failure on demand (PFD). A comparison is made between the estimator of the PFD taking into account all the failures and the estimator taking into account only the detected failures., in French, 19\`eme Congr\`es de Ma\^itrise des Risques et S\^uret\'e de Fonctionnement, Lambda-Mu'2014, Oct 2014, Dijon, France

Deleuze Gilles. Sept dessins. In: Chimères. Revue des schizoanalyses, N°21, hiver 1994. Félix Guattari — vol 1. pp. 13-20.