Sébastien Tiran

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Side-channel attacks (SCAs) are a serious threat against security of cryptographic algorithms. Most of the countermeasures proposed to protect cryptosystems against these attacks, are efficient but present a significant area and power consumption overhead. The registers being the main weakness of cryptosystems, the source of leaks the more easily(More)
This paper introduces a leakage model in the frequency domain to enhance the efficiency of side channel attacks of CMOS circuits. While usual techniques are focused on noise removal around clock harmonics, we show that the actual leakage is not necessary located in those expected bandwidths as experimentally observed by Mateos and Gebotys (A new correlation(More)
Side-channel analysis is one of the most efficient techniques available to an attacker to break the security of a cryptographic device. Started as monitoring of computation time or power, it has evolved into considering several other possible information leakage sources, such as electromagnetic (EM) emissions. EM waves can be a very attractive means to(More)
This paper introduces Side-Channel Analysis results obtained on an unprotected circuit characterized by a surprisingly non-linear leakage. While in such a case, Correlation Power Analysis is not adapted, we show that a more generic attack, based on the Analysis Of Variance (AOV) outperfoms CPA. It has the advantage of detecting non-linear leakage, unlike(More)
Magnitude Squared Coherence is a signal processing tool that indicates how well two time domain signals match one with the other by tracking linear dependencies in their spectral decomposition. This paper introduces different ways of using the Magnitude Squared Coherence for Side Channel Analysis. This distinguisher has several advantages over well-known(More)
EM emissions can be a rich source of leakage for side-channel analysis of cipher implementations. In this paper, we describe a set of novel countermeasures based on dynamic spatial relocation and dynamic mappings, and validate the protection provided by them against EM attacks. The countermeasures improve significantly the security of the circuit.
The use of Dynamic Voltage and Frequency Scaling technique (DVFS) in Systems-on-Chip is becoming more and more common. This technique, re-named RDVFS for the occasion, has recently been proposed as a countermeasure against Side Channel Attacks (SCA) through the randomization of the choices of V and F, at the expense of power consumption. In this paper,(More)