Sandy2X: new curve25519 speed records

T. Chou

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

16 Citations (Scopus)


This paper sets speed records on well-known Intel chips for the Curve25519 elliptic-curve Diffie-Hellman scheme and the Ed25519 digital signature scheme. In particular, it takes only 159 128 Sandy Bridge cycles or 156 995 Ivy Bridge cycles to compute a Diffie-Hellman shared secret, while the previous records are 194 036 Sandy Bridge cycles or 182 708 Ivy Bridge cycles. There have been many papers analyzing elliptic-curve speeds on Intel chips, and they all use Intel’s serial 64×64 → 128-bit multiplier for field arithmetic. These papers have ignored the 2-way vectorized 32 × 32 → 64-bit multiplier on Sandy Bridge and Ivy Bridge: it seems obvious that the serial multiplier is faster. However, this paper uses the vectorized multiplier. This is the first speed record set for elliptic-curve cryptography using a vectorized multiplier on Sandy Bridge and Ivy Bridge. Our work suggests that the vectorized multiplier might be a better choice for elliptic-curve computation, or even other types ofcomputation that involve prime-field arithmetic, even in the case where the computation does not exhibit very nice internal parallelism.

Original languageEnglish
Title of host publicationSelected Areas in Cryptography – SAC 2015
Subtitle of host publication22nd International Conference, Sackville, NB, Canada, August 12–14, 2015, Revised Selected Papers
Place of PublicationDordrecht
Number of pages16
ISBN (Electronic)978-3-319-31301-6
ISBN (Print)978-3-319-31300-9
Publication statusPublished - 2016
Event22nd International Conference on Selected Areas in Cryptography (SAC 2015) - Sackville, Canada
Duration: 12 Aug 201514 Aug 2015
Conference number: 22

Publication series

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


Conference22nd International Conference on Selected Areas in Cryptography (SAC 2015)
Abbreviated titleSAC 2015


  • Constant time
  • Curve25519
  • Diffie-Hellman
  • Ed25519
  • Elliptic curves
  • Signatures
  • Speed
  • Vectorization


Dive into the research topics of 'Sandy2X: new curve25519 speed records'. Together they form a unique fingerprint.

Cite this