Verfahren zur Sicherung von Modularen Potenzierungs- oder Punktmultiplikationsoperationen gegen Seitenkanalangriffe

Details

Veröffentlichungs-Nr.

EP4723538

Anmeldetag

1. Oktober 2024

Veröffentlichung

8. April 2026

Rechtsraum

EP

IPC

H04L9/00, H04L9/30

Abstract

The present invention relates to a method for securing against side channel attacks an execution of a cryptographic process comprising either: - an elliptic curve scalar multiplication operation of a secret key k with a first point P of an elliptic curve, thereby computing a scalar multiplication operation result Q = k.P, with k a scalar, or - a modular exponentiation operation of a base P, which is a first positive integer number, with a secret key k, k being an integer, computing a modular exponentiation operation result Q = P<k> mod m. The main idea of the invention is to store pre-computed results of an ECC scalar multiplication Si=si.P or of an exponentiation Si= P<si> mod m and then, for computing a target result of a scalar multiplication k.P or of an exponentiation P<k> mod m, to compute the difference between the target result and a pre-computed result (k-s).P or P<k-s>. The target result can then be easily obtained by combining the pre-computed result and the computed difference.

Anmelder

Firma

THALES DIS FRANCE SAS

Land

🇫🇷 Frankreich