# Elliptical curve converting device and device and system for use thereof

• CN 1,235,446 A
• Filed: 03/04/1999
• Published: 11/17/1999
• Est. Priority Date: 03/05/1998
• Status: Abandoned Application
##### First Claim
Patent Images

1. elliptic curve E of a conversion and generate the elliptical curve converting device of other elliptic curves Et comprises:

• Receive the parameter a of prime number p, elliptic curve E and parameter b from the outside, as the receiving system of first G of basic point, wherein elliptic curve E is defined within on the limited body GF (p), represents with y^2=x^3+ax+b, and first G is present on the elliptic curve E, (x0 y0) represents with G=;

Obtain the conversion coefficient acquisition device that is present in the conversion coefficient t on the limited body GF (p), conversion coefficient t t ≠

0 that satisfies condition wherein, and, to compare with prime number p, the figure place of t^4 * a (modp) is few;

Calculate the parameter a '"'"', parameter b of elliptic curve Et '"'"' and elliptic curve calculating apparatus of the new Gt of basic point unit according to following formula with the described conversion coefficient t that obtains,a′

=a×

t^4b′

=b×

t^6xt0=t^2×

x0yt0^3×

y0Wherein elliptic curve Et is defined within on the limited body GF (p), represents with y '"'"' ^2=x '"'"' ^3+a '"'"' * x '"'"'+b '"'"', and xt0, yt0 are respectively x coordinate figure, the y coordinate figures of first Gt;

Described parameter a '"'"', b '"'"' that calculates to outside output and the output device of first Gt.

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