Bonjour tout le monde, Dans le cadre des séminaires de l'équipe Sécurité /Systèmes, nous écouterons Yackolley Amoussou-Guenou, MCF à l'Université Paris-Panthéon-Assas et le centre de recherche CRED, jeudi 07/12/2023 à 10h30. Yackolley Amoussou-Gueno nous parlera de ses travaux sur "Ethereum Proof-of-Stake under Scrutiny". Résumé : Ethereum has undergone a recent change called the Merge, which made Ethereum a Proof-of-Stake blockchain shifting closer to BFT consensus. Ethereum, which wished to keep the best of the two protocol designs (BFT and Nakomoto-style), now has a convoluted consensus protocol as its core. The result is a blockchain being possibly produced in a tree-like form while participants try to finalize blocks. We categorize different attacks jeopardizing the liveness of the protocol. The Ethereum community has responded by creating patches against some of them. We discovered a new attack on the patched protocol. To support our analysis, we propose a new high-level formalization of the properties of liveness and availability of the Ethereum blockchain, and we provide a pseudo-code. We believe this formalization to be helpful for other analyses as well. Our results yield that the Ethereum Proof-of-Stake has safety but only probabilistic liveness. The probability of the liveness is influenced by the parameter describing the time frame allowed for validators to change their mind about the current main chain. Joint work with Ulysse Pavloff and Sara Tucci-Piergiovanni (CEA-List, Université Paris-Saclay). Bio : Yackolley Amoussou-Guenou is associated professor (maître de conférences) in computer science at Université Paris-Panthéon-Assas, in the CRED research center. He was previously researcher at CEA-List, Université Paris-Saclay. He holds a PhD from Sorbonne Université and a M.Sc. from Université Paris Cité (ex- Paris-Diderot), both degrees in theoretical computer science. He works on various aspects of distributed systems, and in particular on the blockchain technologies: the consensus protocols, the distribution of rewards, and the use of game theory to study the incentives. More generally, his research interests span from distributed systems to algorithmic game theory and their combination. Cordialement, Ghada Gharbi ________________________________________________________________________________ Réunion Microsoft Teams Participez à partir de votre ordinateur, de votre application mobile ou de l’appareil de la salle Cliquez ici pour rejoindre la réunion ID de la réunion : 355 366 181 466 Code secret : jSvE2T Télécharger Teams | Rejoindre sur le web Pour en savoir plus | Options de réunion ________________________________________________________________________________ [cid:206faf58-e98c-4f57-afb4-99312c055790]<https://www.epita.fr/> Ghada GHARBI Enseignante - Chercheure EPITA Toulouse [cid:a1051f2e-87b2-4245-b32f-77bd4c872fd3]<https://www.facebook.com/epita… [cid:51a3bc82-95ba-42e6-a531-a2aae2e65f85] <https://www.instagram.com/epita.national/> [cid:8dfe7ccb-c5af-41ec-9fa3-74e425bab26a] <https://www.linkedin.com/school/epita-ecole-ingenieurs-informatique> [cid:bee4ed5b-f540-4b37-9019-6661a176d062] <https://twitter.com/epita> [cid:76b31b86-fe95-4eb9-82fc-4b8e32c213f2] <https://www.epita.fr/> [cid:b28098f7-14b4-4078-8606-ef5ac44088c8] <https://www.youtube.com/channel/UC33NtVL7bStj4FmWeIstKqg> ______________________ Doctorants mailing list -- doctorants(a)ml.lre.epita.fr https://lists.lrde.epita.fr/postorius/lists/doctorants.ml.lre.epita.fr// ______________________ Docs mailing list -- docs(a)ml.lre.epita.fr https://lists.lrde.epita.fr/postorius/lists/docs.ml.lre.epita.fr// ______________________ Docs.lyon mailing list -- docs.lyon(a)ml.lre.epita.fr https://lists.lrde.epita.fr/postorius/lists/docs.lyon.ml.lre.epita.fr//