International Association
for Cryptologic Research

In this paper we propose new methods to blind exponents

used in RSA and in elliptic curves based algorithms. Due to classical

differential power analysis (DPA and CPA), a lot of countermeasures to

protect exponents have been proposed since 1999 Kocher [20] and by

Coron [13]. However, these blinding methods present some drawbacks

regarding execution time and memory cost. It also got some weaknesses.

Indeed they could also be targeted by some attacks such as The Carry

Leakage on the Randomized Exponent proposed by P.A. Fouque et al.

in [23] or inefficient against some others analysis such as Single Power

Analysis. In this article, we explain how the most used method could

be exploited when an attacker can access test samples. We target here

new dynamic blinding methods in order to prevent from any learning

phase and also to improve the resistance against the latest side channel

analyses published.