561 research outputs found
Discrete logarithms in curves over finite fields
A survey on algorithms for computing discrete logarithms in Jacobians of
curves over finite fields
Still Wrong Use of Pairings in Cryptography
Several pairing-based cryptographic protocols are recently proposed with a
wide variety of new novel applications including the ones in emerging
technologies like cloud computing, internet of things (IoT), e-health systems
and wearable technologies. There have been however a wide range of incorrect
use of these primitives. The paper of Galbraith, Paterson, and Smart (2006)
pointed out most of the issues related to the incorrect use of pairing-based
cryptography. However, we noticed that some recently proposed applications
still do not use these primitives correctly. This leads to unrealizable,
insecure or too inefficient designs of pairing-based protocols. We observed
that one reason is not being aware of the recent advancements on solving the
discrete logarithm problems in some groups. The main purpose of this article is
to give an understandable, informative, and the most up-to-date criteria for
the correct use of pairing-based cryptography. We thereby deliberately avoid
most of the technical details and rather give special emphasis on the
importance of the correct use of bilinear maps by realizing secure
cryptographic protocols. We list a collection of some recent papers having
wrong security assumptions or realizability/efficiency issues. Finally, we give
a compact and an up-to-date recipe of the correct use of pairings.Comment: 25 page
Counting points on hyperelliptic curves with explicit real multiplication in arbitrary genus
We present a probabilistic Las Vegas algorithm for computing the local zeta
function of a genus- hyperelliptic curve defined over with
explicit real multiplication (RM) by an order in a degree-
totally real number field.
It is based on the approaches by Schoof and Pila in a more favorable case
where we can split the -torsion into kernels of endomorphisms, as
introduced by Gaudry, Kohel, and Smith in genus 2. To deal with these kernels
in any genus, we adapt a technique that the author, Gaudry, and Spaenlehauer
introduced to model the -torsion by structured polynomial systems.
Applying this technique to the kernels, the systems we obtain are much smaller
and so is the complexity of solving them.
Our main result is that there exists a constant such that, for any
fixed , this algorithm has expected time and space complexity as grows and the characteristic is large enough. We prove that
and we also conjecture that the result still holds for .Comment: To appear in Journal of Complexity. arXiv admin note: text overlap
with arXiv:1710.0344
Index calculus for abelian varieties of small dimension and the elliptic curve discrete logarithm problem
International audienceWe propose an index calculus algorithm for the discrete logarithm problem on general abelian varieties of small dimension. The main difference with the previous approaches is that we do not make use of any embedding into the Jacobian of a well-suited curve. We apply this algorithm to the Weil restriction of elliptic curves and hyperelliptic curves over small degree extension fields. In particular, our attack can solve an elliptic curve discrete logarithm problem defined over GF(q^3) in heuristic asymptotic running time O~(q^(4/3)); and an elliptic problem over GF(q^4) or a genus 2 problem over GF(q^2) in heuristic asymptotic running time O~(q^(3/2))
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