a prime field, including complete, quadratic, and twisted Edwards curves, is presented. An
overview of the properties of these three classes of curves is given. Generalization of the
results known for the classes of complete and quadratic curves to the class of twisted
Edwards curves is obtained. A modified law of point's addition is used to correctly determine
the isogeny degree.
The analysis of the 2-isogeny existence conditions of generalized Edwards form curves over
a prime field, including complete, quadratic, and twisted Edwards curves, is presented. An
overview of the properties of these three classes of curves is given. Generalization of the
results known for the classes of complete and quadratic curves to the class of twisted
Edwards curves is obtained. A modified law of point's addition is used to correctly determine
the isogeny degree.