Presentation 2015-09-04
Improved addition algorithm for Edwards Curve
Masaaki Shirase,
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Abstract(in Japanese) (See Japanese page)
Abstract(in English) This paper introduces a new coordinate system (named ${cal P}times {cal P}$ coordinate system) in which a point $(x,y)$ in affine is represented as $[X,Y,Z,W]$ satisfying $x=X/Z,y=Y/W$ and then proposes new algorithms for computing addition and duplication on Edwards curve $x^2+y^2=1+dx^2y^2$. Given $P$ in ${cal P}times {cal P}$ and $Q$ in affine, $P+Q$ and $2P$ take 8{bf M} and 3{bf M}+4{bf S}, respectively, where $M$ and $S$ are multiplication and squaring cost. This paper also proposes algorithms for computing addtion and duplication on twisted Edwards curve $ax^2+y^2=1+dx^2y^2$. Addition takes 9{bf M}, or 7{bf M} when $a=-1$. Duplication takes 6{cal M}+3{cal S}, or 3{bf M}+4{cal S} when $a=-1$.
Keyword(in Japanese) (See Japanese page)
Keyword(in English) elliptic curve cryptosystem / Edwards curve / addition algorithm / coordinate system
Paper # ISEC2015-25
Date of Issue 2015-08-28 (ISEC)

Conference Information
Committee ISEC
Conference Date 2015/9/4(1days)
Place (in Japanese) (See Japanese page)
Place (in English) Kikai-Shinko-Kaikan Bldg.
Topics (in Japanese) (See Japanese page)
Topics (in English)
Chair Yukiyasu Tsunoo(NEC)
Vice Chair Masahiro Mambo(Kanazawa Univ.) / Kazuto Ogawa(NHK)
Secretary Masahiro Mambo(AIST) / Kazuto Ogawa(Toshiba)
Assistant Tetsuya Izu(Fujitsu Lab.) / Takaaki Mizuki(Tohoku Univ.) / Noritaka Yamashita(NEC)

Paper Information
Registration To Technical Committee on Information Security
Language JPN
Title (in Japanese) (See Japanese page)
Sub Title (in Japanese) (See Japanese page)
Title (in English) Improved addition algorithm for Edwards Curve
Sub Title (in English)
Keyword(1) elliptic curve cryptosystem
Keyword(2) Edwards curve
Keyword(3) addition algorithm
Keyword(4) coordinate system
1st Author's Name Masaaki Shirase
1st Author's Affiliation Future University Hakodate(Future Univ Hakodate)
Date 2015-09-04
Paper # ISEC2015-25
Volume (vol) vol.115
Number (no) ISEC-215
Page pp.pp.1-8(ISEC),
#Pages 8
Date of Issue 2015-08-28 (ISEC)