Cryptology ePrint Archive: Report 2008/334

Analyzing the Galbraith-Lin-Scott Point Multiplication Method for Elliptic Curves over Binary Fields

Darrel Hankerson and Koray Karabina and Alfred Menezes

Abstract: Galbraith, Lin and Scott recently constructed efficiently-computable endomorphisms for a large family of elliptic curves defined over F_{q^2} and showed, in the case where q is prime, that the Gallant-Lambert-Vanstone point multiplication method for these curves is significantly faster than point multiplication for general elliptic curves over prime fields. In this paper, we investigate the potential benefits of using Galbraith-Lin-Scott elliptic curves in the case where q is a power of 2. The analysis differs from the q prime case because of several factors, including the availability of the point halving strategy for elliptic curves over binary fields. Our analysis and implementations show that Galbraith-Lin-Scott offers significant acceleration for curves over binary fields, in both doubling- and halving-based approaches. Experimentally, the acceleration surpasses that reported for prime fields (for the platform in common), a somewhat counterintuitive result given the relative costs of point addition and doubling in each case.

Category / Keywords: public-key cryptography / elliptic curve, point multiplication, GLV method, isogeny

Date: received 1 Aug 2008, last revised 7 Oct 2008

Contact author: hankedr at auburn edu

Available format(s): PDF | BibTeX Citation

Note: Minor revision; updated data from eprint 2008/194.

Version: 20081007:200349 (All versions of this report)

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