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Paper: Asymptotic complexities of discrete logarithm algorithms in pairing-relevant finite fields

Authors:
Gabrielle De Micheli , Inria Nancy, Université de Lorraine, France
Pierrick Gaudry , CNRS, Université de Lorraine, France
Cecile Pierrot , Inria Nancy, Université de Lorraine, France
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DOI: http://dx.doi.org/10.1007/978-3-030-56880-1_2 (login may be required)
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Presentation: Slides
Conference: CRYPTO 2020
Abstract: We study the discrete logarithm problem at the boundary case between small and medium characteristic finite fields, which is precisely the area where finite fields used in pairing-based cryptosystems live. In order to evaluate the security of pairing-based protocols, we thoroughly analyze the complexity of all the algorithms that coexist at this boundary case: the Quasi-Polynomial algorithms, the Number Field Sieve and its many variants, and the Function Field Sieve. We adapt the latter to the particular case where the extension degree is composite, and show how to lower the complexity by working in a shifted function field. All this study finally allows us to give precise values for the characteristic asymptotically achieving the highest security level for pairings. Surprisingly enough, there exist special characteristics that are as secure as general ones.
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BibTeX
@inproceedings{crypto-2020-30374,
  title={Asymptotic complexities of discrete logarithm algorithms in pairing-relevant finite fields},
  publisher={Springer-Verlag},
  doi={http://dx.doi.org/10.1007/978-3-030-56880-1_2},
  author={Gabrielle De Micheli and Pierrick Gaudry and Cecile Pierrot},
  year=2020
}