Group Key Exchange from CSIDH and Its Application to Trusted Setup in Supersingular Isogeny Cryptosystems

Tomoki Moriya, Katsuyuki Takashima, Tsuyoshi Takagi

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

Abstract

In this paper, we propose a multi-party (group) key exchange protocol based on CSIDH (Commutative Supersingular Isogeny Diffie–Hellman), which is a post-quantum Diffie-Hellman type key exchange protocol from a commutative group action. The proposed group key exchange protocol called G-CSIDH uses the same size prime modulus p as that in CSIDH for the same security level, and the security of G-CSIDH is reduced to the security of CSIDH. In addition, we propose the trusted protocol of generating public parameters of supersingular isogeny cryptosystems by using the proposed G-CSIDH. Trust in the setup based on G-CSIDH is reduced to the security of G-CSIDH, and then that of CSIDH. The trusted protocol can be applied to any supersingular isogeny cryptosystem, which uses a supersingular elliptic curve as a public parameter.

Original languageEnglish
Title of host publicationInformation Security and Cryptology - 15th International Conference, Inscrypt 2019, Revised Selected Papers
EditorsZhe Liu, Moti Yung
PublisherSpringer
Pages86-98
Number of pages13
ISBN (Print)9783030429201
DOIs
Publication statusPublished - 2020
Externally publishedYes
Event15th International Conference on Information Security and Cryptology, Inscrypt 2019 - Nanjing, China
Duration: 2019 Dec 62019 Dec 8

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume12020 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference15th International Conference on Information Security and Cryptology, Inscrypt 2019
CountryChina
CityNanjing
Period19/12/619/12/8

Keywords

  • CSIDH
  • Group key exchange
  • Isogeny-based cryptography

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science(all)

Fingerprint Dive into the research topics of 'Group Key Exchange from CSIDH and Its Application to Trusted Setup in Supersingular Isogeny Cryptosystems'. Together they form a unique fingerprint.

Cite this