Hidden Stabilizers, the Isogeny To Endomorphism Ring Problem and the Cryptanalysis of pSIDH

Mingjie Chen, Muhammad Imran, Gábor Ivanyos, Peter Kutas*, Antonin Leroux, Christophe Petit

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The Isogeny to Endomorphism Ring Problem (IsERP) asks to compute the endomorphism ring of the codomain of an isogeny between supersingular curves in characteristic p given only a representation for this isogeny, i.e. some data and an algorithm to evaluate this isogeny on any torsion point. This problem plays a central role in isogeny-based cryptography; it underlies the security of pSIDH protocol (ASIACRYPT 2022) and it is at the heart of the recent attacks that broke the SIDH key exchange. Prior to this work, no efficient algorithm was known to solve IsERP for a generic isogeny degree, the hardest case seemingly when the degree is prime.

In this paper, we introduce a new quantum polynomial-time algorithm to solve IsERP for isogenies whose degrees are odd and have many prime factors. As main technical tools, our algorithm uses a quantum algorithm for computing hidden Borel subgroups, a group action on supersingular isogenies from EUROCRYPT 2021, various algorithms for the Deuring correspondence and a new algorithm to lift arbitrary quaternion order elements modulo an odd integer N with many prime factors to powersmooth elements.

As a main consequence for cryptography, we obtain a quantum polynomial-time key recovery attack on pSIDH. The technical tools we use may also be of independent interest.
Original languageEnglish
Title of host publicationAdvances in Cryptology – ASIACRYPT 2023
Subtitle of host publication29th International Conference on the Theory and Application of Cryptology and Information Security, Guangzhou, China, December 4–8, 2023, Proceedings, Part III
EditorsJian Guo, Ron Steinfeld
Place of PublicationSingapore
PublisherSpringer
Pages99-130
Number of pages31
Volume3
Edition1
ISBN (Electronic)9789819987276
ISBN (Print)9789819987269
DOIs
Publication statusPublished - 18 Dec 2023
Event29th International Conference on the Theory and Application of Cryptology and Information Security, ASIACRYPT 2023 - Guangzhou, China
Duration: 4 Dec 20238 Dec 2023

Publication series

NameLecture Notes in Computer Science
Volume14440
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference29th International Conference on the Theory and Application of Cryptology and Information Security, ASIACRYPT 2023
Abbreviated titleASIACRYPT 2023
Country/TerritoryChina
CityGuangzhou
Period4/12/238/12/23

Bibliographical note

Acknowledgements
Gábor Ivanyos is supported in part by the Hungarian Ministry of Innovation and Technology NRDI Office within the framework of the Artificial Intelligence National Laboratory Program. Péter Kutas is supported by the Hungarian Ministry of Innovation and Technology NRDI Office within the framework of the Quantum Information National Laboratory Program, the J’anos Bolyai Research Scholarship of the Hungarian Academy of Sciences and by the UNKP-22-5 New National Excellence Program. Mingjie Chen, Péter Kutas and Christophe Petit are partly supported by EPSRC through grant number EP/V011324/1.

Fingerprint

Dive into the research topics of 'Hidden Stabilizers, the Isogeny To Endomorphism Ring Problem and the Cryptanalysis of pSIDH'. Together they form a unique fingerprint.

Cite this