arkq / sm2349 Goto Github PK

//test if y^2=x^3+ax+b
epoint_get(point, x, y);
power(x, 3, para_p, x_3);        //x_3=x^3 mod p
multiply(x, para_a, x);           //x=a*x
divide(x, para_p, tmp);          //x=a*x mod p  , tmp=a*x/p
add(x_3, x, x);                     //x=x^3+ax
add(x, para_b, x);                  //x=x^3+ax+b
divide(x, para_p, tmp);             //x=x^3+ax+b mod p
power(y, 2, para_p, y);          //y=y^2 mod p
if (mr_compare(x, y) != 0)
    return ERR_NOT_VALID_POINT;
else return 0;