I wanna create the safe Twisted Edward curve. As far as I know, The number of curve points must be $\#E=8r$ that $r$ is big prime number. Also the number of points of quadratic twist of this curve must be $\#E'=4r'$ that $r'$ is big prime number. I search the value of $d$ for $-x^2+y^2=1+dx^2y^2$ that satisfices these properties. I know that $d$ must be nonquadratic number in $F_p$ and $p=1 \ mod(4)$.I had ran the sage app for finding proper $d$ for almost three months. But The program hasn't find this yet.
Are there any efficient ways for finding proper $d$? What happen If my curve isn't the quadratic twist secure? Are there any way that I set the $r$ and create the curve fit to it?
