Paper 2005/340

A New Approach to Counteract DPA Attacks on Block Ciphers

Christophe Giraud and Emmanuel Prouff

Abstract

Since the publication of Differential Power Analysis (DPA) in 1998, many countermeasures have been published to counteract this very efficient kind of attacks. All these countermeasures follow the same approach : they try to make sensitive operations uncorrelated with the input. Such a method is very costly in terms of both timing and memory space. In this paper, we suggest a new approach where block ciphers are designed to inherently thwart DPA attacks. The idea we develop in this paper is based on a theoretical analysis of DPA attacks and it essentially consists in embedding existing iterated block ciphers in a secure layer. We analyse the security of our proposal and we show that it induces very small overheads.