An Efficient Authenticated Key Exchange from Random Self-reducibility on CSIDH

Tomoki Kawashima, Katsuyuki Takashima, Yusuke Aikawa, Tsuyoshi Takagi

研究成果: Conference contribution

1 被引用数 (Scopus)

抄録

SIDH and CSIDH are key exchange protocols based on isogenies and conjectured to be quantum-resistant. Since the protocols are similar to the classical Diffie–Hellman, they are vulnerable to the man-in-the-middle attack. A key exchange which is resistant to such an attack is called an authenticated key exchange (AKE), and many isogeny-based AKEs have been proposed. However, the parameter sizes of the existing schemes should be large since they all have relatively large security losses in security proofs. This is partially because the random self-reducibility of isogeny-based decisional problems has not been proved yet. In this paper, we show that the computational problem and the gap problem of CSIDH are random self-reducible. A gap problem is a computational problem given access to the corresponding decision oracle. Moreover, we propose a CSIDH-based AKE with small security loss, following the construction of Cohn-Gordon et al. in CRYPTO 2019, as an application of the random self-reducibility of the gap problem of CSIDH. Our AKE is proved to be the fastest CSIDH-based AKE when we aim at 110-bit security level.

本文言語English
ホスト出版物のタイトル23rd International Conference, 2020, Proceedings
編集者Deukjo Hong
出版社Springer Science and Business Media Deutschland GmbH
ページ58-84
ページ数27
ISBN(印刷版)9783030688899
DOI
出版ステータスPublished - 2021
外部発表はい
イベント23rd International Conference on Information Security and Cryptology, ICISC 2020 - Seoul, Korea, Republic of
継続期間: 2020 12 22020 12 4

出版物シリーズ

名前Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
12593 LNCS
ISSN(印刷版)0302-9743
ISSN(電子版)1611-3349

Conference

Conference23rd International Conference on Information Security and Cryptology, ICISC 2020
CountryKorea, Republic of
CitySeoul
Period20/12/220/12/4

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science(all)

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