Sonia Belaïd

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Leakage-resilient cryptography aims at developing new algorithms for which physical security against side-channel attacks can be formally analyzed. Following the work of Dziembowski and Pietrzak at FOCS 2008, several symmetric cryptographic primitives have been investigated in this setting. Most of them can be instantiated with a block cipher as underlying(More)
The prevailing approach for building masked algorithms that can resist higher-order differential power analysis is to develop gadgets, that is, masked gates used as atomic blocks, that securely implement basic operations from the original algorithm, and then to compose these gadgets, introducing refresh operations at strategic places to guarantee that the(More)
Many cryptographic algorithms are vulnerable to side channel analysis and several leakage models have been introduced to better understand these flaws. In 2003, Ishai, Sahai and Wagner introduced the d-probing security model, in which an attacker can observe at most d intermediate values during a processing. They also proposed an algorithm that securely(More)
A side-channel analysis of multiplication in GF(2) has recently been published by Belaı̈d, Fouque and Gérard at Asiacrypt 2014, with an application to AES-GCM. Using the least significant bit of the Hamming weight of the multiplication result, the authors have shown how to recover the secret multiplier efficiently. However such least significant bit is very(More)
In the paper, we study whether it is possible to construct an efficient leakage-resilient symmetric scheme using the AES block cipher. We aim at bridging the gap between the theoretical leakage-resilient symmetric primitives used to build encryption schemes and the practical schemes that do not have any security proof against side-channel adversaries. Our(More)
Differential power analysis (DPA) is a side-channel attack in which an adversary retrieves cryptographic material by measuring and analyzing the power consumption of the device on which the cryptographic algorithm under attack executes. An effective countermeasure against DPA is to mask secrets by probabilistically encoding them over a set of shares, and to(More)
Securing cryptographic implementations against side-channel attacks is one of the most important challenges in modern cryptography. Many countermeasures have been introduced for this purpose, and analyzed in specialized security models. Formal solutions have also been proposed to extend the guarantees of provable security to physically observable devices.(More)
As any algorithm manipulating secret data, HMAC is potentially vulnerable to side channel attacks. In 2007, McEvoy et al. proposed a differential power analysis attack against HMAC instantiated with hash functions from the SHA-2 family. Their attack works in the Hamming distance leakage model and makes strong assumptions on the target implementation. In(More)