### 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.

Available format(s)
Category
Implementation
Publication info
Published elsewhere. INDOCRYPT 2018
Keywords
CSIDHPost-Quantum CryptographySupersingular Elliptic Curve Isogenies
Contact author(s)
michael meyer @ hs-rm de
History
2018-11-02: revised
See all versions
Short URL
https://ia.cr/2018/782

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},
note = {\url{https://eprint.iacr.org/2018/782}},
url = {https://eprint.iacr.org/2018/782}
}

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