English

On the Distribution of Atkin and Elkies Primes

Number Theory 2014-06-20 v2

Abstract

Given an elliptic curve E over a finite field F_q of q elements, we say that an odd prime ell not dividing q is an Elkies prime for E if t_E^2 - 4q is a square modulo ell, where t_E = q+1 - #E(F_q) and #E(F_q) is the number of F_q-rational points on E; otherwise ell is called an Atkin prime. We show that there are asymptotically the same number of Atkin and Elkies primes ell < L on average over all curves E over F_q, provided that L >= (log q)^e for any fixed e > 0 and a sufficiently large q. We use this result to design and analyse a fast algorithm to generate random elliptic curves with #E(F_p) prime, where p varies uniformly over primes in a given interval [x,2x].

Keywords

Cite

@article{arxiv.1112.3390,
  title  = {On the Distribution of Atkin and Elkies Primes},
  author = {Igor E. Shparlinski and Andrew V. Sutherland},
  journal= {arXiv preprint arXiv:1112.3390},
  year   = {2014}
}

Comments

17 pages, minor edits