English

Extending Lenstra's Primality Test to CM elliptic curves and a new quasi-quadratic Las Vegas algorithm for primality

Number Theory 2022-12-23 v2

Abstract

For an elliptic curve with CM by KK defined over its Hilbert class field, E/HE/H, we extend Lenstra's finite fields test to generators of norms of certain ideals in OH\mathcal{O}_H, yielding a sufficient O~(log3N)\widetilde{O}(\log^3 N) primality test and partially answering an open question of Lemmermeyer in the case of CM elliptic curves. Letting ι,γ,bOK\iota,\gamma, b\in \mathcal{O}_K, (ι)(\iota) prime, and bb a primitive kk-th root of unity modulo (ι)n(\iota)^n we specialize this test to rational integers of the form NK/Q(γιn+b)N_{K/\mathbb{Q}}(\gamma\iota^n+b) with the norm of γ\gamma small, giving a Las Vegas test for primality with average runtime O~(log2N)\widetilde{O}(\log^2 N), that further certifies primality of such integers in O~(log2N)\widetilde{O}(\log^2 N) for nearly all choices of input parameters. The integers tested were not previously amenable to quasi-quadratic heuristic primality certification.

Keywords

Cite

@article{arxiv.2212.04463,
  title  = {Extending Lenstra's Primality Test to CM elliptic curves and a new quasi-quadratic Las Vegas algorithm for primality},
  author = {Tejas Rao},
  journal= {arXiv preprint arXiv:2212.04463},
  year   = {2022}
}