ACCESS

Algebraic Coding and Cryptography
Seminar Series

Online Event

ACCESS is a joint effort designed to highlight world-class research in coding theory, cryptography, and related areas and to encourage collaboration among its participants.

Next seminar
Apr 02

Tako Boris Fouotsa
EPFL

Biography.  Boris is a postdoctoral researcher at the LASEC group at EPFL since March 2022, under the supervision of Serge Vaudenay. Previously, he was a PhD student at the

University of Roma Tre (Italy), under the supervision of Christophe Petit and Fabrizio Barroero. Before joining the University of Roma Tre in February 2019, he obtained his master degree at the University of Yaoundé I in Cameroon. He is also a trained mathematics teacher from École Normale Supérieure Yaoundé.  His research focuses mostly on Isogeny-Based Cryptography. He is interested in the design of new isogeny-based protocols, and in the cryptanalysis of existing ones. He has been interested in new ways to use of elliptic curves in factoring recently. Feel free to check his webpage (https://borisfouotsa.github.io/) for more details about his research, or reach out to him directly.

Computing isogenies from a single torsion point image, and more. 

Abstract.  If you have been following the "Supersingular Post" recently, then you are probably aware that an isogeny of degree d can be efficiently recovered from its action on a basis of some accessible N-torsion group where N is smooth. This led to attacks over SIDH and SIKE, two popular isogeny-based protocols in which images of torsion points through the secret isogenies are public. It is natural to ask whether one can efficiently recover an isogeny when having access to "less" torsion point information?

In this talk we will answer the question above in the affirmative. In fact, we will show that one can recover an isogeny of degree d from its action on a single (accessible) torsion point  of smooth order N^2, assuming d<N^2. We will then establish a framework, modular isogeny problems, for the study of isogeny problems with (none to full) torsion point information. This framework enables a unified view of most of the fundamental computational problems appearing in Isogeny-Based Cryptography. This presentation is based on a joint work with Luca De Feo and Lorenz Panny, work which will appear at Eurocrypt 2024.

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Organizing team

Jean-Francois Biasse - University of South Florida

Hiram Lopez - Virginia Tech

Felice Manganiello - Clemson University

Gretchen Matthews - Virginia Tech

Edoardo Persichetti - Florida Atlantic University

Material made avaliable to us by the speakers will be posted in the archive page.  

ACCESS calendar