[Resource Topic] 2007/410: Inverted Edwards coordinates

Welcome to the resource topic for 2007/410

Title:
Inverted Edwards coordinates

Authors: Daniel J. Bernstein, Tanja Lange

Abstract:

Edwards curves have attracted great interest for several reasons. When curve parameters are chosen properly, the addition formulas use only 10M+1S. The formulas are {\it strongly unified}, i.e., work without change for doublings; even better, they are {\it complete}, i.e., work without change for all inputs. Dedicated doubling formulas use only 3M+4S, and dedicated tripling formulas use only 9M+4S. This paper introduces {\it inverted Edwards coordinates}. Inverted Edwards coordinates (X_1:Y_1:Z_1) represent the affine point (Z_1/X_1,Z_1/Y_1) on an Edwards curve; for comparison, standard Edwards coordinates (X_1:Y_1:Z_1) represent the affine point (X_1/Z_1,Y_1/Z_1). This paper presents addition formulas for inverted Edwards coordinates using only 9M+1S. The formulas are not complete but still are strongly unified. Dedicated doubling formulas use only 3M+4S, and dedicated tripling formulas use only 9M+4S. Inverted Edwards coordinates thus save 1M for each addition, without slowing down doubling or tripling.

ePrint: https://eprint.iacr.org/2007/410

See all topics related to this paper.

Feel free to post resources that are related to this paper below.

Example resources include: implementations, explanation materials, talks, slides, links to previous discussions on other websites.

For more information, see the rules for Resource Topics .