有限體上之超橢圓曲線的同構類

Abstract

在這篇論文裡,我們得到了有限體F_q上之超橢圓曲線在genus為4且特徵值等於2的同構類個數。我們得到了以下的公式: N=2q^7+q^4-q^3 若2整除m N=2q^7+q^4-q^3+4q^2-4q+4 若6整除m N=2q^7+q^4-q^3+4q^2-4q+16 若2整除m,但若6不整除m ,其中q=2^m。這個結果可以被用在超橢圓函數密碼系統(HECC)之上。

In this thesis we will find the number of isomorphism classes of hyperelliptic curves of genus 4 over a finite field F_q with characteristic 2. We prove the formula of the number N of isomorphism classes as the following: N=2q^7+q^4-q^3 if 2 divides m N=2q^7+q^4-q^3+4q^2-4q+4 if 6 divides m N=2q^7+q^4-q^3+4q^2-4q+16 if 2 divides m,but 6 does not divide m. These results can be used in the classification problems and the hyperelliptic curve cryptosystems.