International Association for Cryptologic Research

International Association
for Cryptologic Research

IACR News item: 27 January 2014

PhD Database PhD Database
Name: Abdelaziz Elaabid
Topic: Side channel attacks: advanced experimentations on template attacks
Category: secret-key cryptography

Description: In the 90\'s, the emergence of new cryptanalysis methods revolutionized the security of cryptographic devices. These attacks are based on power consumption analysis, when the microprocessor is running the cryptographic algorithm. Especially, we analyse in this thesis some properties of the template attack, with examples from attacks against an unprotected ASIC implementation. We point out that the efficiency of template attacks can be unleashed by using a relevent power model, and we provide some practical improvements by the use of different signal processing techniques. Furthermore, we investigate the relevance of the theoretical framework on profiled SCAs presented by F.-X. Standaert et al. at Eurocrypt 2009. The analyse consists in a case-study based on side-channel measurements acquired experimentally from a hardwired cryptographic accelerator. Therefore, with respect to previous formal analyses carried out on software measurements or on simulated data, the investigations we describe are more complex, due to the underlying chip\'s architecture and to the large amount of algorithmic noise.In this context, we explore the appropriateness of different choices for the sensitive variables, and we show that a skilled attacker aware of the register transfers occurring during the cryptographic operations can select the most adequate distinguisher, thus increasing its success rate. The principal component analysis (PCA) is used to represent the templates in some dimensions, and we give a physical interpretation of the templates eigenvalues and eigenvectors. We introduce a method based on the thresholding of leakage data to accelerate the profiling or the matching stages. This method empowers an attacker, in that it saves traces when converging towards correct values of the secret. Concretely, we demonstrate a 5 times speed-up in the on-line phase of the attack. Also, it has been underlined that the various samples garnered during the same acquisition can carry complement[...]
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