1,474 research outputs found
Summation polynomials and the discrete logarithm problem on elliptic curves
The aim of the paper is the construction of the index calculus
algorithm for the discrete logarithm problem on elliptic curves.
The
construction presented here is based on the problem of finding
bounded solutions to some explicit modular multivariate
polynomial equations. These equations arise from the elliptic
curve summation polynomials introduced here and may be computed
easily. Roughly speaking, we show that given the algorithm for
solving such equations, which works in polynomial or low
exponential time in the size of the input, one finds discrete
logarithms faster than by means of Pollard\u27s methods
Point compression for the trace zero subgroup over a small degree extension field
Using Semaev's summation polynomials, we derive a new equation for the
-rational points of the trace zero variety of an elliptic curve
defined over . Using this equation, we produce an optimal-size
representation for such points. Our representation is compatible with scalar
multiplication. We give a point compression algorithm to compute the
representation and a decompression algorithm to recover the original point (up
to some small ambiguity). The algorithms are efficient for trace zero varieties
coming from small degree extension fields. We give explicit equations and
discuss in detail the practically relevant cases of cubic and quintic field
extensions.Comment: 23 pages, to appear in Designs, Codes and Cryptograph
A Las Vegas algorithm to solve the elliptic curve discrete logarithm problem
In this paper, we describe a new Las Vegas algorithm to solve the elliptic
curve discrete logarithm problem. The algorithm depends on a property of the
group of rational points of an elliptic curve and is thus not a generic
algorithm. The algorithm that we describe has some similarities with the most
powerful index-calculus algorithm for the discrete logarithm problem over a
finite field
Character sums with division polynomials
We obtain nontrivial estimates of quadratic character sums of division
polynomials , , evaluated at a given point on an
elliptic curve over a finite field of elements. Our bounds are nontrivial
if the order of is at least for some fixed . This work is motivated by an open question about statistical
indistinguishability of some cryptographically relevant sequences which has
recently been brought up by K. Lauter and the second author
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))
On Index Calculus Algorithms for Subfield Curves
In this paper we further the study of index calculus methods for solving the elliptic curve discrete logarithm problem (ECDLP). We focus on the index calculus for subfield curves, also called Koblitz curves, defined over Fq with ECDLP in Fqn. Instead of accelerating the solution of polynomial systems during index calculus as was predominantly done in previous work, we define factor bases that are invariant under the q-power Frobenius automorphism of the field Fqn, reducing the number of polynomial systems that need to be solved. A reduction by a factor of 1/n is the best one could hope for. We show how to choose factor bases to achieve this, while simultaneously accelerating the linear algebra step of the index calculus method for Koblitz curves by a factor n2. Furthermore, we show how to use the Frobenius endomorphism to improve symmetry breaking for Koblitz curves. We provide constructions of factor bases with the desired properties, and we study their impact on the polynomial system solving costs experimentally.SCOPUS: cp.kinfo:eu-repo/semantics/publishe
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