# Improving NFS for the discrete logarithm problem in non-prime finite fields

2 GRACE - Geometry, arithmetic, algorithms, codes and encryption
LIX - Laboratoire d'informatique de l'École polytechnique [Palaiseau], Inria Saclay - Ile de France
3 CARAMEL - Cryptology, Arithmetic: Hardware and Software
Inria Nancy - Grand Est, LORIA - ALGO - Department of Algorithms, Computation, Image and Geometry
Abstract : The aim of this work is to investigate the hardness of the discrete logarithm problem in fields GF($p^n$) where $n$ is a small integer greater than $1$. Though less studied than the small characteristic case or the prime field case, the difficulty of this problem is at the heart of security valuations for torus-based and pairing-based cryptography. The best known method for solving this problem is the Number Field Sieve (NFS). A key ingredient in this algorithm is the ability to find good polynomials that define the extension fields used in NFS. We design two new methods for this task, modifying the asymptotic complexity and paving the way for record-breaking computations. We exemplify these results with the computation of discrete logarithms over a field GF($p^2$) whose cardinality is 180 digits (595 bits) long.
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Conference papers

Cited literature [31 references]

https://hal.inria.fr/hal-01112879
Contributor : Aurore Guillevic <>
Submitted on : Friday, June 3, 2016 - 2:27:01 AM
Last modification on : Thursday, November 21, 2019 - 6:32:53 PM
Long-term archiving on: Sunday, September 4, 2016 - 10:10:21 AM

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### Citation

Razvan Barbulescu, Pierrick Gaudry, Aurore Guillevic, François Morain. Improving NFS for the discrete logarithm problem in non-prime finite fields. Eurocrypt 2015 - 34th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Apr 2015, Sofia, Bulgaria. pp.129-155, ⟨10.1007/978-3-662-46800-5_6⟩. ⟨hal-01112879v2⟩

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