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Leakage detection usually refers to the task of identifying data-dependent information in side-channel measurements, independent of whether this information can be exploited. Detecting Points-Of-Interest (POIs) in leakage traces is a complementary task that is a necessary first step in most side-channel attacks, where the adversary wants to turn this information into (e.g.) a key recovery. In this paper, we discuss the differences between these tasks, by investigating a popular solution to leakage detection based on a t-test, and an alternative method exploiting Pearson's correlation coecient. We rst show that the simpler t-test has better sampling complexity, and that its gain over the correlation-based test can be predicted by looking at the Signal-to-Noise Ratio (SNR) of the leakage partitions used in these tests. This implies that the sampling complexity of both tests relates more to their implicit leakage assumptions than to the actual statistics exploited.We also put forward that this gain comes at the cost of some intuition loss regarding the localization of the exploitable leakage samples in the traces, and their informativeness. Next, and more importantly, we highlight that our reasoning based on the SNR allows dening an improved t-test with signicantly faster detection speed (with approximately 5 times less measurements in our experiments), which is therefore highly relevant for evaluation laboratories. We nally conclude that whereas t-tests are the method of choice for leakage detection only, correlation-based tests exploiting larger partitions are preferable for detecting POIs.We conrm this intuition by improving automated tools for the detection of POIs in the leakage measurements of a masked implementation, in a black box manner and without key knowledge, thanks to a correlation-based leakage detection test.

Algebraic fault analysis (AFA), which combines algebraic cryptanalysis with fault attacks, has represented serious threats to the security of lightweight block ciphers. Inspired by an earlier framework for the analysis of side-channel attacks presented at EUROCRYPT 2009, a new generic framework is proposed to analyze and evaluate algebraic fault attacks on lightweight block ciphers. We interpret AFA at three levels: the target, the adversary and the evaluator. We describe the capability of an adversary in four parts: the fault injector, the fault model describer, the cipher describer and the machine solver. A formal fault model is provided to cover most of current fault attacks. Different strategies of building optimal equation set are also provided to accelerate the solving process. At the evaluator level, we consider the approximate information metric and the actual security metric. These metrics can be used to guide adversaries, cipher designers and industrial engineers. To verify the feasibility of the proposed framework, we make a comprehensive study of AFA on an ultra-lightweight block cipher called LBlock. Three scenarios are exploited which include injecting a fault to encryption, to key scheduling, or modifying the round number or counter. Our best results show that a single fault injection is enough to recover the master key of LBlock within the affordable complexity in each scenario. To verify the generic feature of the proposed framework, we apply AFA to three other block ciphers, i.e., DES, PRESENT and Twofish. The results demonstrate that our framework can be used for different ciphers with different structures.

Symmetric ciphers purposed for Fully Homomorphic Encryption (FHE) have recently been proposed for two main reasons. First, minimizing the implementation (time and memory) overheads that are inherent to current FHE schemes. Second, improving the homomorphic capacity, i.e. the amount of operations that one can perform on homomorphic ciphertexts before bootstrapping, which amounts to limit their level of noise. Existing solutions for this purpose suggest a gap between block ciphers and stream ciphers. The first ones typically allow a constant but small homomorphic capacity, due to the iteration of rounds eventually leading to complex Boolean functions (hence large noise). The second ones typically allow a larger homomorphic capacity for the first ciphertext blocks, that decreases with the number of ciphertext blocks (due to the increasing Boolean complexity of the stream ciphers’ output). In this paper, we aim to combine the best of these two worlds, and propose a new stream cipher construction that allows constant and small(er) noise. Its main idea is to apply a Boolean (filter) function to a public bit permutation of a constant key register, so that the Boolean complexity of the stream cipher outputs is constant. We also propose an instantiation of the filter function designed to exploit recent (3rd-generation) FHE schemes, where the error growth is quasi-additive when adequately multiplying ciphertexts with the same amount of noise. In order to stimulate further investigation, we then specify a few instances of this stream cipher, for which we provide a preliminary security analysis. We finally highlight the good properties of our stream cipher regarding the other goal of minimizing the time and memory complexity of calculus delegation (for 2nd-generation FHE schemes). We conclude the paper with open problems related to the large design space opened by these new constructions.

The 1st EuNetAir Air Quality Joint Intercomparison Exercise organized in Aveiro (Portugal) from 13th–27th October 2014, focused on the evaluation and assessment of environmental gas, particulate matter (PM) and meteorological microsensors, versus standard air quality reference methods through an experimental urban air quality monitoring campaign. The IDAD-Institute of Environment and Development Air Quality Mobile Laboratory was placed at an urban traffic location in the city centre of Aveiro to conduct continuous measurements with standard equipment and reference analysers for CO, NOx, O3, SO2, PM10, PM2.5, temperature, humidity, wind speed and direction, solar radiation and precipitation. The comparison of the sensor data generated by different microsensor-systems installed side-by-side with reference analysers, contributes to the assessment of the performance and the accuracy of microsensor-systems in a real-world context, and supports their calibration and further development. The overall performance of the sensors in terms of their statistical metrics and measurement profile indicates significant differences in the results depending on the platform and on the sensors considered. In terms of pollutants, some promising results were observed for O3 (r2: 0.12–0.77), CO (r2: 0.53–0.87), and NO2 (r2: 0.02–0.89). For PM (r2: 0.07–0.36) and SO2 (r2: 0.09–0.20) the results show a poor performance with low correlation coefficients between the reference and microsensor measurements. These field observations under specific environmental conditions suggest that the relevant microsensor platforms, if supported by the proper post processing and data modelling tools, have enormous potential for new strategies in air quality control.

A fast method for the radiation analysis of arbitrary oriented planes is presented. It combines an adaptive spectral integration scheme and a recently proposed unequally-spaced fast Laplace transform algorithm. It is illustrated on the free-space Green's function through an example where an important speed-up factor is evaluated compared to the brute force spectral integration.

This work presents a novel localization scheme based on Ultra-Wideband (UWB) channel sounding, employing a triangulation method that makes use of the geometrical properties of propagation paths, such as time of arrival (ToA), angle of departure (AoD) and angle of arrival (AoA). An extension to the high-resolution RiMAX algorithm was developed, facilitating the analysis of UWB frequency-dependent propagation parameters, allowing for the localization of a target node in Line-of-Sight (LoS), Obstructed-LoS (OLoS), and Non-LoS (NLoS) scenarios.

This paper presents a stabilization ofa Radio-Frequency Quadrupole simulation based on the quasi-Helmholtz projectors. A boundary element method applied to this case undergoes a low-frequency breakdown i.e the associated system of equations becomes increasingly ill-conditioned fordecreasing frequencies. This in practice implies that the convergence of iterative methods which are used to solve the linear system is poor. This paper reports that a quasi-Helmholtz projectors based stabilization is sucient to handle the level of realismrequired by applications.

Objective: To assess the extent and evolution of tissue abnormality of tubers, perituber tissue, and normal-appearing white matter (NAWM) in patients with tuberous sclerosis complex using serial diffusion tensor imaging. Methods: We applied automatic segmentation based on a combined global-local intensity mixture model of 3T structural and 35 direction diffusion tensor MRIs (diffusion tensor imaging) to define 3 regions: tuber tissue, an equal volume perituber rim, and the remaining NAWM. For each patient, scan, lobe, and tissue type, we analyzed the averages of mean diffusivity (MD) and fractional anisotropy (FA) in a generalized additive mixed model. Results: Twenty-five patients (mean age 5.9 years; range 0.5-24.5 years) underwent 2 to 6 scans each, totaling 70 scans. Average time between scans was 1.2 years (range 0.4-2.9). Patient scans were compared with those of 73 healthy controls. FA values were lowest, and MD values were highest in tubers, next in perituber tissue, then in NAWM. Longitudinal analysis showed a positive (FA) and negative (MD) correlation with age in tubers, perituber tissue, and NAWM. All 3 tissue types followed a biexponential developmental trajectory, similar to the white matter of controls. An additional qualitative analysis showed a gradual transition of diffusion values across the tissue type boundaries. Conclusions: Similar to NAWM, tuber and perituber tissues in tuberous sclerosis complex undergo microstructural evolution with age. The extent of diffusion abnormality decreases with distance to the tuber, in line with known extension of histologic, immunohistochemical, and molecular abnormalities beyond tuber pathology.

In this live demonstration, we present the microsystem integration of a palladium-based MEMS capacitive hydrogen gas sensor and its sub-components. The system includes all the elements of the data acquisition chain. The MEMS device is interfaced by a capacitance-to-digital converter for signal conditioning, and a microcontroller associated to a radio for both data processing and transmitting. Moreover a specific housing has been designed with trade consideration, including a Porex® microporous polymer membrane for moisture protection. Finally, a dedicated graphic user interface has been implemented with assisted calibration or recording procedures, and an oscilloscope for data monitoring. Thanks to compatibilities with ZigBee or Bluetooth low energy protocols, this system is directly dedicated to interconnected sensor nodes applications within the Internet-of-Things vision.

Rank estimation is an important tool for side-channel evaluations laboratories. It allows determining the remaining security after an attack has been performed, quantied as the time complexity required to brute force the key given the leakages. Several solutions to rank estimation have been introduced in the recent years. In this paper, we rst clarify the connections between these solutions, by organizing them according to their (maximum likelihood or weak maximum likelihood) strategy and whether they take as argument a side-channel distinguishers' output or some evaluation metrics. This leads us to introduce new combinations of these approaches, and to discuss the use of weak maximum likelihood strategies for suboptimal but highly parallel enumeration. Next, we show that the dierent approaches to rank estimation can also be implemented with dierent mixes of very similar tools (e.g. histograms, convolutions, combinations and subsampling). Eventually, we provide various experiments allowing to discuss the pros and cons of these dierent approaches, hence consolidating the literature on this topic.

Fresh re-keying is a type of protocol which aims at splitting the task of protecting an encryption/authentication scheme against side-channel attacks in two parts. One part, a re-keying function, has to satisfy a minimum set of properties (such as good diusion), and is based on an algebraic structure that is easy to protect against side-channel attacks with countermeasures such as masking. The other part, a block cipher, brings resistance against mathematical cryptanalysis, and only has to be secure against single measurement attacks. Since fresh re-keying schemes are cheap and stateless, they are convenient to use in practice and do not require any synchronization between communication parties. However, it has been shown that their rst instantiation (from Africacrypt 2010) only provides birthday security because of a (mathematical only) collision-based key recovery attack recently put forward by Dobraunig et al. (CARDIS 2014). In this paper, we provide two provably secure (in the ideal cipher model) solutions to avoid such collision attacks. The rst one is based on classical block ciphers, but does not achieve beyond birthday CPA security (i.e. it only provably prevents the CARDIS 2014 key recovery attack) and requires an additional block cipher execution in the protocol. The second one is based on tweakable block ciphers and provides tight CPA security while also being more ecient. As a complement, we also show that our reasoning extends to hybrid schemes, where the communication party to protect against side-channel attacks is stateful. We illustrate this claim by describing a collision attack against an example of a hybrid scheme patented by Kocher, and presenting a tweak leading to beyond birthday security. We conclude the paper by discussing the use of fresh/hybrid re-keying for encryption and authentication, together with a cautionary note on their side-channel resistance.

The design of a linear Vivaldi antenna array for water leaks detection is presented. We show the 3D antenna design with the bandwidth of interest between 250-2000 MHz, which is necessary for sufficient depth penetration and high resolution imaging and characterization. New modifications on features with respect to the traditional Vivaldi antenna design are discussed. The radiation patterns show that the directivity increases with frequency. Near-fields in E and H planes in the front of the antenna are depicted and display smooth spreading over a sufficiently narrow area of radiation exposure. The impact of the ground on the antenna is analyzed. The complete design of a linear array of 4 elements is presented, and the mutual coupling between elements is illustrated.

A Radio Frequency Quadrupole (RFQ) is an essential part of linear accelerator (LINAC). It is situated at the very beginning of the accelerator and has three important functions: focusing, bunching and acceleration. The RFQ prepares the beam before its injection into the strong acceleration cavities and so it impacts the behaviour of the beam in the whole accelerator. Hence, it must be designed as reliable and efficient as possible. At the present time, the simulation of the electromagnetic fields and beam dynamics are carried out with some approximations in order to obtain a reasonable computation time. However, faster and more accurate solvers would first allow us to better understand the RFQ technology for high beam currents and second would potentially allow us to perform some numerical optimization. Our main objective is to develop a fast and accurate solver for the electromagnetic fields and for the beam dynamics. Our laboratory is specialized in fast methods for the electromagnetic fields simulation of antennas. Our solvers are based on the Method of Moments (MoM) in the frequency domain. This method could be applied as well for the electromagnetic fields simulation in accelerating cavities. One of the main advantages of the MoM in comparison to finite elements is that it requires only unknowns on the surface of the cavity. For high beam current, it would be very convenient to be able to calculate simultaneously the equations of motion and the Maxwell’s equations since the fields scattered due to the space charge can be as strong as the source fields. Such a simulation is so-called a self-consistent simulation.

This paper describes a low-cost innovative technique to characterize aperture arrays based on a near field pattern measurement. This measurement is used to validate a numerical method code, based on the method of moments, capable of realizing accurate electromagnetic simulations of very large non-regular arrays containing up to thousands of elements which are tens of wavelengths in diameter. A practical application of the technique and the code can be found for low frequency aperture arrays in radio astronomy applications, such as the SKA telescope.

Initially studied and developed by students in universities, the very small pico satellites (with a mass lower than 1 Kg) are more and more considered for science applications. In particular they will be used in constellations of small spacecraft for remote sensing of various regions of the magnetosphere. They require a payload with specific size, weight and power consumption. In order to respond to this demand, new instruments have to be developed. Those instruments should exhibit at least the same performance as those used in larger satellites while fulfilling the specific requirements imposed by the size of the satellites. For this reason, we currently develop a xylophone bar magnetometer (XBM) based on micro-electromechanical systems (MEMS) with integrated detector electronics. The principle of this magnetometer is based on classical resonating xylophone bar. A sinusoidal current oscillating at the fundamental transverse resonant frequency of the bar is applied to the bar. When an external magnetic field is present, the resulting Lorentz force causes the bar to vibrate at its fundamental frequency with a displacement directly proportional to the amplitude in one direction of the ambient magnetic field. When designing a MEMS XBM, the detection method is a crucial aspect. The measurement method largely influences the geometry of the magnetometer as well as the manufacturing technology. Due to the constraints in terms of size, weight and power consumption, the two most promising measurement methods identified are capacitive and piezoelectric. Designs which include these measurement techniques are presented and simulated under realistic conditions. A new configuration of PZT/Pt structure is introduced and leads to much better sensitivity than the traditional Pt/PZT/Pt sandwich structure. The principle of the electronic circuits enabling high sensitivity and low power consumption is presented. Finally, a design including lateral electrodes for capacitive measurement

The Blind Source Separation (BSS) problem is often solved by maximizing objective functions reflecting the statistical dependency between outputs. Since global maximization may be difficult without exhaustive search, criteria for which it can be proved that all the local maxima correspond to an acceptable solution of the BSS problem have been developed. These criteria are used in a deflation procedure. This paper shows that the “spurious maximum free” property still holds for the minimum range approach when the sources are extracted simultaneously.

La formation d’ingénieur à l’Université catholique de Louvain a été réorganisée selon un principe de pédagogie active (apprentissage par problèmes et par projets). Ainsi, il est proposé aux étudiants qui entament leur spécialisation en électricité ou en électromécanique, un projet leur permettant d’aborder à la fois les notions d’électromagnétisme et les notions de circuits électriques et de faire le lien entre ces deux matières. Dans cet article, nous présentons en détails un de ces projets, consistant pour les étudiants à réaliser un capteur de suivi de ligne, ainsi que son électronique de traitement. Des variantes sont également exposées, s’articulant autour de différents types de capteurs intégrés. Nous détaillons les moyens et l’approche mis en oeuvre et tirons les conclusions relatives à l’organisation de ces projets.