Method of secure multiplication between a sparse polynomial and a dense polynomial in a cryptographic algorithm, associated electronic device and computer program.

Abstract

Method of secure multiplication in between a sparse polynomial and a dense polynomial of the form where is such that =- characterized in that is of the form where is between 0 and such that = , and is a coefficient such that ,- and in that it comprises for all ranging from 0 to:a. the initialization (E4) of an intermediate result polynomial;b. the initialization (E12) of other intermediate polynomials such that for all ranging from 0 to ;c. steps (E22) of polynomial multiplication carrying out for all ranging from 0 to , , having as value the index of the step concerned;d. the updating (E34) of by adding to it the other intermediate polynomials. Figure for the abstract: fig. 2.

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