Paper 2004/197

SPA-based attack against the modular reduction within a partially secured RSA-CRT implementation

Helmut Kahl

Abstract

This note describes an SPA-based side channel attack against a CRT implementation of an RSA function. In contrast with Novak’s attack [8], it concentrates on the initial modular reduction. With the help of lattice reduction it applies even to implementations which use a common randomising technique to ensure resistance against certain side channel attacks.