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In geometry, the Hessian curve is a plane curve similar to folium of Descartes. It is named after the German mathematician Otto Hesse. This curve was suggested for application in elliptic curve cryptography, because arithmetic in this curve representation is faster and needs less memory than arithmetic in standard Weierstrass form.〔Cauchy-Desbove's Formulae: ''Hessian-elliptic Curves and Side-Channel Attacks'', Marc Joye and Jean-Jacques Quisquarter〕 == Definition == Let be a field and consider an elliptic curve in the following special case of Weierstrass form over : : where the curve has discriminant Then the point has order 3. To prove that has order 3, note that the tangent to at is the line which intersects with multiplicity 3 at . Conversely, given a point of order 3 on an elliptic curve both defined over a field one can put the curve into Weierstrass form with so that the tangent at is the line . Then the equation of the curve is with . Now, to obtain the Hessian curve, it is necessary to do the following transformation: First let denote a root of the polynomial : Then : Note that if has a finite field of order (mod 3), then every element of has a unique cube root; in general, lies in an extension field of ''K''. Now by defining the following value another curve, C, is obtained, that is birationally equivalent to E: : : which is called ''cubic Hessian form'' (in projective coordinates) : : in the ''affine plane'' ( satisfying and ). Furthermore, (otherwise, the curve would be singular). Starting from the Hessian curve, a birationally equivalent Weierstrass equation is given by : under the transformations: : and : where: : and : 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Hessian form of an elliptic curve」の詳細全文を読む スポンサード リンク
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