Elliptic Gau{\ss} sums and Schoof's algorithm

Abstract

We present a new approach to handling the case of Atkin primes in Schoof's algorithm for counting points on elliptic curves over finite fields. Our approach is based on the theory of polynomially cyclic algebras, which we recall as far as necessary. We then proceed to describe our method, which essentially relies on transferring costly computations in extensions of $\mathbb{F}_p$ to isomorphic ones endowed with a special structure allowing to reduce run-time. We analyse the new run-time and conclude this procedure yields some improvement as compared to the classical approaches.