Proposta de um fluxo de ataque DPA para avaliar a vulnerabilidade de arquiteturas criptográficas protegidas por aleatorização de processamento

Abstract

Side-channel Attacks (SCA) are an effective way to reveal information being processed by cryptographic systems. Such attacks were introduced by Paul Kocher, in (KOCHER; JAFFE; JUN, 1999), and aims to compromise the implementation of the cryptographic algorithms instead their algorithmic vulnerabilities. In other words, it is not sufficient for an algorithm to be robust to guarantee the communication confidentiality, it is necessary that its implementation be robust, too. To ensure such robustness one can find in the literature numerous proposals of cryptographic systems aiming to counteract such kind of attack. The GALS pipeline architectures proposed in (SOARES et al., 2011) are recent in the literature and combine more than one countermeasure to side channel attacks, such as random clock frequencies and simultaneous processing of two or more pipeline stages. Such architectures have been proved robust to conventional side channel attacks. However one can find in the literature several proposals aiming to increase the efficiency of such kind of attack, using digital signal processing tools in order to counteract the countermeasures implemented on such cryptographic systems. The present work aims to investigate such digital signal processing techniques and present an attack flow capable to compromise cryptographic systems with countermeasures. The GALS pipeline architectures presented in (SOARES et al., 2011) will be used as case study, since they implement more than one countermeasure. The experiments which this work is based were performed on two configurations of such architecture and have been successful to identify the criptographic key being used. The exploration of more complex configurations has been characterized for future experiments