CTIDH: faster constant-time CSIDH

Open Access
Authors
  • G. Banegas
  • D.J. Bernstein
  • F. Campos
  • T. Chou
Publication date 11-08-2021
Journal IACR Transactions on Cryptographic Hardware and Embedded Systems
Volume | Issue number 2021 | 4
Pages (from-to) 351–387
Organisations
  • Interfacultary Research - Institute for Logic, Language and Computation (ILLC)
Abstract This paper introduces a new key space for CSIDH and a new algorithm for constant-time evaluation of the CSIDH group action. The key space is not useful with previous algorithms, and the algorithm is not useful with previous key spaces, but combining the new key space with the new algorithm produces speed records for constant-time CSIDH. For example, for CSIDH-512 with a 256-bit key space, the best previous constant-time results used 789000 multiplications and more than 200 million Skylake cycles; this paper uses 438006 multiplications and 125.53 million cycles.
Document type Article
Language English
Published at https://doi.org/10.46586/tches.v2021.i4.351-387
Downloads
TCHES2021_4_12 (Final published version)
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