A faster way to the CSIDH

Michael Meyer; Steffen Reith

Paper 2018/782

A faster way to the CSIDH

Michael Meyer and Steffen Reith

Abstract

Recently Castryck, Lange, Martindale, Panny, and Renes published CSIDH, a new key exchange scheme using supersingular elliptic curve isogenies. Due to its small key sizes, and the possibility of a non-interactive and a static-static key exchange, CSIDH seems very interesting for practical applications. However, the performance is rather slow. Therefore, we employ some techniques to speed up the algorithms, mainly by restructuring the elliptic curve point multiplications and by using twisted Edwards curves in the isogeny image curve computations, yielding a speed-up factor of 1.33 in comparison to the implementation of Castryck et al. Furthermore, we suggest techniques for constant-time implementations.

Metadata

Available format(s): PDF
Category: Implementation
Publication info: Published elsewhere. INDOCRYPT 2018
Keywords: CSIDH Post-Quantum Cryptography Supersingular Elliptic Curve Isogenies
Contact author(s): michael meyer @ hs-rm de
History: 2018-11-02: revised; 2018-09-01: received; See all versions
Short URL: https://ia.cr/2018/782
License: CC BY

BibTeX

@misc{cryptoeprint:2018/782,
      author = {Michael Meyer and Steffen Reith},
      title = {A faster way to the {CSIDH}},
      howpublished = {Cryptology {ePrint} Archive, Paper 2018/782},
      year = {2018},
      url = {https://eprint.iacr.org/2018/782}
}