Jacobians of Hyperelliptic Curves

New Features:

• Two new Order functions are provided to compute the order of a point P on a Jacobian J where the order of P or of J is bounded and where (optionally) some modular information is known about that order. Being able to use this extra information dramatically improves the running time of the Order routines. These are due to P. Gaudry.
• The function Frobenius applies the Frobenius to a point on a Jacobian.
• The function WeilPairing computes the Weil pairing of two points on a Jacobian defined over a finite field.
• The Order function for Jacobians over finite fields has been rewritten by P. Gaudry. Jacobians defined over a curve of genus 2 are treated separately. More generally some specific algorithms are provided to deal with some special cases.