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Index Calculus in Class Groups of Plane Curves of Small Degree

Authors:
Claus Diem
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URL: http://eprint.iacr.org/2005/119
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Abstract: We present a novel index calculus algorithm for the discrete logarithm problem (DLP) in degree 0 class groups of curves over finite fields. A heuristic analysis of our algorithm indicates that asymptotically for varying q, ``essentially all'' instances of the DLP in degree 0 class groups of curves represented by plane models of a fixed degree d over $\mathbb{F}_q$ can be solved in an expected time of $\tilde{O}(q^{2 -2/(d-2)})$. A particular application is that heuristically, ``essentially all'' instances of the DLP in degree 0 class groups of non-hyperelliptic curves of genus 3 (represented by plane curves of degree 4) can be solved in an expected time of $\tilde{O}(q)$. We also provide a method to represent ``sufficiently general'' (non-hyperelliptic) curves of genus $g \geq 3$ by plane models of degree $g+1$. We conclude that on heuristic grounds the DLP in degree 0 class groups of ``sufficiently general'' curves of genus $g \geq 3$ (represented initially by plane models of bounded degree) can be solved in an expected time of $\tilde{O}(q^{2 -2/(g-1)})$.
BibTeX
@misc{eprint-2005-12455,
  title={Index Calculus in Class Groups of Plane Curves of Small Degree},
  booktitle={IACR Eprint archive},
  keywords={public-key cryptography / discrete logarithm problem},
  url={http://eprint.iacr.org/2005/119},
  note={ diem@iem.uni-due.de 12891 received 18 Apr 2005},
  author={Claus Diem},
  year=2005
}