Organiser: Xavier Caruso (CNRS, Poncelet Laboratory) . ... Isogenies are an essential tool in Elliptic Curves cryptography, where they are used in a wide variety of area: fast point counting, complex multiplication methods.. V lu's formulas give an efficient method for computing such isogenies, but there were no known formulas for computing isogenies for hyperelliptic curves of higher genus, except in particuliar cases. ... Poncelet Laboratory web page . ...