Paper 2014/852 Original: eprint.iacr.org/2014/852 ↗

Faster ECC over $\mathbb{F}_{2^{521}-1}$

Robert Granger
Michael Scott
Abstract

In this paper we present a new multiplication algorithm for residues modulo the Mersenne prime $2^{521} - 1$. Using this approach, on an Intel Haswell Core i7-4770, constant-time variable-base scalar multiplication on NIST's (and SECG's) curve P-521 requires 1,073,000 cycles, while on the recently proposed Edwards curve E-521 it requires just 943,000 cycles. As a comparison, on the same architecture openSSL's ECDH speed test for curve P-521 requires 1,319,000 cycles. Furthermore, our code was written entirely in C and so is robust across different platforms. The basic observation behind these speedups is that the form of the modulus allows one to multiply residues with as few word-by-word multiplications as is needed for squaring, while incurring very little overhead from extra additions, in contrast to the usual Karatsuba methods.

Metadata
Available format(s)
PDF
Category
Implementation
Publication info
Preprint.
History
2015-03-23: last updated
2014-10-22: published
Short URL
https://ia.cr/2014/852
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2014/852,
      author = {Robert Granger and Michael Scott},
      title = {Faster ECC over $\mathbb{F}_{2^{521}-1}$},
      howpublished = {Cryptology {ePrint} Archive, Paper 2014/852},
      year = {2014},
      url = {https://eprint.iacr.org/2014/852}
}
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