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Moignot, Bénédicte. "Caractérisation des sous-unités principales et auxiliaires des canaux sodium dépendant du potentiel exprimées dans le système nerveux central de l'insecte periplaneta americana". Phd thesis, Université d'Angers, 2010. http://tel.archives-ouvertes.fr/tel-00491350.
Pełny tekst źródłaDehbaoui, Amine. "Analyse Sécuritaire des Émanations Électromagnétiques des Circuits Intégrés". Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20020.
Pełny tekst źródłaThe integration of cryptographic primitives in different electronic devices is widely used today incommunications, financial services, government services or PayTV.Foremost among these devices include the smart card. According to a report published in August 2010, IMS Research forecasts that the smart card market will reach 5.8 billion units sold in this year. The vast majority is used in telecommunications (SIM) and banking.The smart card incorporates an integrated circuit which can be a dedicated processor for cryptographic calculations. Therefore, these integrated circuits contain secrets such as secret or private keys used by the symmetric or asymmetric cryptographic algorithms. These keys must remain absolutely confidential to ensure the safety chain.Therefore the robustness of smart cards against attacks is crucial. These attacks can be classifiedinto three main categories: invasive, semi-invasive and non-invasive.Non-invasive attacks can be considered the most dangerous, since this kind of attack can be achieved without any contact with the circuit.Indeed, while using electronic circuits that compose them are subjected to variations in current and voltage. These variations generate an electromagnetic radiation propagating in the vicinity of the circuit.These radiations are correlated with secret information (eg a secret key used for authentication). Several attacks based on these leakages were published by the scientific community.This thesis aims to: (a) understand the different sources of electromagnetic emanations of integrated circuits, and propose a localized near field attack to test the robustness of a cryptographic circuit and (b) propose counter-measures to these attacks
Bukasa, Sébanjila Kevin. "Analyse de vulnérabilité des systèmes embarqués face aux attaques physiques". Thesis, Rennes 1, 2019. http://www.theses.fr/2019REN1S042/document.
Pełny tekst źródłaDuring this thesis, we focused on the security of mobile devices. To do this, we explored physical attacks by perturbation (fault injections) as well as by observation, both based on electromagnetic emissions. We selected two types of targets representing two categories of mobile devices. On the one hand, the microcontrollers that equip IoT devices. And on the other hand the System-on-Chip (SoC) that can be found on smartphones. We focused on the chips designed by ARM. Through physical attacks we wanted to show that it was possible to affect the microarchitecture on which the entire functioning of these systems is based. All the protections that can be implemented later at the software level are based on the microarchitecture and therefore become ineffective when it is attacked. For IoT devices, we have highlighted the possibility of obtaining information or total control of the device by means of a fault injection. In this case, fault injections are used as software attack triggers. They also allow software protection to be bypassed. For smartphone devices, we were initially able to extract information contained within a SoC, using electromagnetic listening and characterization of its behavior. In a second step, we were able to show that in the event of a fault, random behaviours can occur, we characterized and proposed explanations for these behaviours. Demonstrating and on systems more advanced than IoT, it is still possible to use physical attacks. Finally, we proposed possible improvements in relation to our various findings during this work
Wurcker, Antoine. "Etude de la sécurité d’algorithmes de cryptographie embarquée vis-à-vis des attaques par analyse de la consommation de courant". Thesis, Limoges, 2015. http://www.theses.fr/2015LIMO0068/document.
Pełny tekst źródłaCryptography is taking an ever more important part in the life of societies since the users are realising the importance to secure the different aspects of life from citizens means of payment, communication and records of private life to the national securities and armies. During the last twenty years we learned that to mathematically secure cryptography algorithms is not enough because of the vulnerabilities brought by their implementations in a device through an alternative means to get information: side channels. Whether it is from power consumption, time or electromagnetic emissions ... those biases have been evaluated and, since their discovery, the researches of new attacks follow new countermeasures in order to guarantee security of algorithms. This thesis is part of this process and shows several research works about attacks and countermeasures in the fields of side channel and fault injections analysis. The first part is about classic contributions where an attacker wants to recover a secret key when the second part deals with the less studied field of secret specifications recovery
Guiga, Linda. "Software protections for artificial neural networks". Electronic Thesis or Diss., Institut polytechnique de Paris, 2022. http://www.theses.fr/2022IPPAT024.
Pełny tekst źródłaIn a context where Neural Networks (NNs) are very present in our daily lives, be it through smartphones, face and biometrics recognition or even in the medical field, their security is of the utmost importance. If such models leak information, not only could it imperil the privacy of sensitive data, but it could also infringe on intellectual property.Selecting the correct architecture and training the corresponding parameters is time-consuming -- it can take months -- and requires large computational resources. This is why an NN constitutes intellectual property. Moreover, once a malicious user knows the architecture and/or the parameters, multiple attacks can be carried out, such as adversarial ones. Adversarial attackers craft a malicious datapoint by adding a small noise to the original input, such that the noise is undetectable to the human eye but fools the model. Such attacks could be the basis of impersonations. Membership attacks, which aim at leaking information about the training dataset, are also facilitated by the knowledge of a model. More generally, when a malicious user has access to a model, she also has access to the manifold of the model's outputs, making it easier for her to fool the model.Protecting NNs is therefore paramount. However, since 2016, they have been the target of increasingly powerful reverse-engineering attacks. Mathematical reverse-engineering attacks solve equations or study a model's internal structure to reveal its parameters. On the other hand, side-channel attacks exploit leaks in a model's implementation -- such as in the cache or power consumption -- to uncover the parameters and architecture. In this thesis, we seek to protect NN models by changing their internal structure and their software implementation.To this aim, we propose four novel countermeasures. In the first three, we consider a gray-box context where the attacker has partial access to the model, and we leverage parasitic models to counter three types of attacks.We first tackle mathematical attacks that recover a model's parameters based on its internal structure. We propose to add one -- or multiple -- parasitic Convolutional Neural Networks (CNNs) at various locations in the base model and measure the incurred change in the structure by observing the modification in generated adversarial samples.However, the previous method does not thwart side-channel attacks that extract the parameters through the analysis of power or electromagnetic consumption. To mitigate such attacks, we propose to add dynamism to the previous protocol. Instead of considering one -- or several -- fixed parasite(s), we incorporate different parasites at each run, at the entrance of the base model. This enables us to hide a model's input, necessary for precise weight extraction. We show the impact of this dynamic incorporation through two simulated attacks.Along the way, we observe that parasitic models affect adversarial examples. Our third contribution is derived from this, as we suggest a novel method to mitigate adversarial attacks. To this effect, we dynamically incorporate another type of parasite: autoencoders. We demonstrate the efficiency of this countermeasure against common adversarial attacks.In a second part, we focus on a black-box context where the attacker knows neither the architecture nor the parameters. Architecture extraction attacks rely on the sequential execution of NNs. The fourth and last contribution we present in this thesis consists in reordering neuron computations. We propose to compute neuron values by blocks in a depth-first fashion, and add randomness to this execution. We prove that this new way of carrying out CNN computations prevents a potential attacker from recovering a small enough set of possible architectures for the initial model
Di, Battista Jérôme. "Étude des techniques d'analyse de défaillance et de leur utilisation dans le cadre de l’évaluation de la sécurité des composants de traitement de l’information". Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20011/document.
Pełny tekst źródłaThe purpose of failure analysis is to locate the source of a defect in order to characterize it, using different techniques (laser stimulation, light emission, electromagnetic emission...). Moreover, the aim of vulnerability analysis, and particularly side-channel analysis, is to observe and collect various leakages information of an integrated circuit (power consumption, electromagnetic emission ...) in order to extract sensitive data. Although these two activities appear to be distincted, they have in common the observation and extraction of information about a circuit behavior. The purpose of this thesis is to explain how and why these activities should be combined. Firstly it is shown that the leakage due to the light emitted during normal operation of a CMOS circuit can be used to set up an attack based on the DPA/DEMA technique. Then a second method based on laser stimulation is presented, improving the “traditional” attacks by injecting a photocurrent, which results in a punctual increase of the power consumption of a circuit. These techniques are demonstrated on an FPGA device
Goyet, Christopher. "Cryptanalyse algébrique par canaux auxiliaires". Paris 6, 2012. http://www.theses.fr/2012PA066329.
Pełny tekst źródłaAlgebraic Side Channel Attacks (ASCA) are a new kind of attack presented at CHES2009 by Renauld and Standaert. They showed thatside-channel information leads to effective algebraic attacks, butthese results are mostly experiments strongly based on a SAT-solver. In this talk, we will present a theoretical study which explains andcharacterizes the algebraic phase of these attacks. We study a moregeneral algebraic attack based on Grobner basis methods. We show thatthe complexity of the Grobner basis computations in these attacksdepends on a new notion of algebraic immunity that we define, and onthe distribution of the leakage information of the cryptosystem. Weillustrate this analysis by two examples of attacks on block-ciphersAES and PRESENT with usual leakage models: the Hamming weight and theHamming distance models. Finally, a new criterion for effectivealgebraic side channel attacks is defined. This easily computablecriterion unifies both SAT and Grobner attacks. This criterion alsorestricts the choice of resisting S-Box against ASCA. At CHES 2009, Renauld, Standaert and Veyrat- Charvillon introduced a new kind of attack called algebraic side-channel attacks (ASCA). They showed that side-channel information leads to effective algebraic attacks. These results are mostly experiments since strongly based on the use of a SAT solver. This article presents a theoretical study to explain and to characterize the algebraic phase of these attacks. We study more general algebraic attacks based on Gröbner meth- ods. We show that the complexity of the Gröbner basis com- putations in these attacks depends on a new notion of alge- braic immunity defined in this paper, and on the distribution of the leakage information of the cryptosystem. We also study two examples of common leakage models: the Hamming weight and the Hamming distance models. For instance, the study in the case of the Hamming weight model gives that the probability of obtaining at least 64 (resp. 130) linear relations is about 50% for the substitution layer of PRESENT (resp. AES). Moreover if the S-boxes are replaced by functions maximizing the new algebraic immunity criterion then the algebraic attacks (Gröbner and SAT) are intractable. From this theoretical study, we also deduce an invariant which can be easily computed from a given S-box and provides a suffi- cient condition of weakness under an ASCA. This new invari- ant does not require any sophisticated algebraic techniques to be defined and computed. Thus, for cryptographic engi- neers without an advanced knowledge in algebra (e. G. Gröb- ner basis techniques), this invariant may represent an inter- esting tool for rejecting weak S-boxes. We describe a lattice attack on DSA-like signature schemes under the assumption that implicit infor- mation on the ephemeral keys is known. Inspired by the implicit oracle of May and Ritzenhofen presented in the context of RSA (PKC2009), we assume that the ephemeral keys share a certain amount of bits without knowing the value of the shared bits. This work also extends results of Leadbitter, Page and Smart (CHES2004) which use a very similar type of partial information leakage. By eliminating the shared blocks of bits between the ephemeral keys, we provide lattices of small dimension (e. G. Equal to the number of signatures) and thus obtain an efficient attack. More precisely, by using the LLL algorithm, the complexity of the attack is polynomial. We show that this method can work when ephemeral keys share certain amount of MSBs and/or LSBs, as well as contiguous blocks of shared bits in the middle. Under the Gaussian heuristic assumption, theoretical bounds on the number of shared bits in function of the number of signed messages are proven. Experimental results show that we are often able to go a few bits beyond the theoretical bound. For instance, if only 2 shared LSBs on each ephemeral keys of 200 signed messages (with no knowledge about the secret key) then the attack reveals the secret key. The success rate of this attack is about 90% when only 1 LSB is shared on each ephemeral keys associated with about 400 signed messages
Le, Thanh-Ha. "Analyses et mesures avancées du rayonnement électromagnétique d'un circuit intégré". Grenoble INPG, 2007. http://www.theses.fr/2007INPG0097.
Pełny tekst źródłaAnalyze two methods: DifferentiaI Power Analysis (DP A) and the Correlation Power Analysis (CP A). The attacks DPA and CPA are based on a power consumption mode!. However, because of the complexity of the circuit, the fact of having a rigorous model is not realistic. We proposed a new method, Partitioning Power Analysis (PP A), which makes it possible to improve the performance of an attack without a precis consumption mode!. Side channel attacks depend closely on the quality of measured signaIs. The performance of an attack can be definitely reduced if the noise level is too high or if the signaIs are not weIl aligned. We proposed solutions based on signal processing techniques to reduce the noise and the effects generated by the signal misalignment. These solutions make it possible to improve the attack effectiveness
Lomne, Victor. "Power and Electro-Magnetic Side-Channel Attacks : threats and countermeasures". Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20220.
Pełny tekst źródłaIn cryptography, a cipher is considered as a black-box, and an attacker has only access to plaintexts and ciphertexts. But a real world cryptographic device leaks additionnal sensitive informations during a cryptographic operation, such as power consumption or electro-magnetic radiations. As a result, several techniques, called Side-Channel Attacks, allow exploiting these physical leakages to break ciphers with a very low complexity in comparison with methods of classical cryptanalysis. In this work, power and electro-magnetic Side-Channel Attacks are firstly studied from an algorithmic point-of-view, and some improvements are proposed. Then, a particular attention is given on the exploitation of the electro-magnetic side-channel, and a simulation flow predicting magnetic radiations of ICs is proposed and validated on two microcontrollers. Finally, some countermeasures allowing to protect ciphers against these threats, based on balanced logic styles, are presented and evaluated
Belaïd, Sonia. "Security of cryptosystems against power-analysis attacks". Thesis, Paris, Ecole normale supérieure, 2015. http://www.theses.fr/2015ENSU0032/document.
Pełny tekst źródłaSide-channel attacks are the most efficient attacks against cryptosystems. While the classical blackbox attacks only exploit the inputs and outputs of cryptographic algorithms, side-channel attacks also get use of the physical leakage released by the underlying device during algorithms executions. In this thesis, we focus on one kind of side-channel attacks which exploits the power consumption of the underlying device to recover the algorithms secret keys. They are gathered under the term power-analysis attacks. Most of the existing power-analysis attacks rely on the observations of variables which only depend on a few secret bits using a divide-and-conquer strategy. In this thesis, we exhibit new kinds of attacks which exploit the observation of intermediate variables highly dependent on huge secrets. In particular, we show how to recover a 128-bit key by only recording the leakage of the Galois multiplication’s results between several known messages and this secret key. We also study two commonly used algorithmic countermeasures against side-channel attacks: leakage resilience and masking. On the one hand, we define a leakage-resilient encryption scheme based on a regular update of the secret key and we prove its security. On the other hand, we build, using formal methods, a tool to automatically verify the security of masked algorithms. We also exhibit new security and compositional properties which can be used to generate masked algorithms at any security order from their unprotected versions. Finally, we propose a comparison between these two countermeasures in order to help industrial experts to determine the best protection to integrate in their products, according to their constraints in terms of security and performances
Cheng, Wei. "What can information guess ? : Towards information leakage quantification in side-channel analysis". Electronic Thesis or Diss., Institut polytechnique de Paris, 2021. http://www.theses.fr/2021IPPAT044.
Pełny tekst źródłaCryptographic algorithms are nowadays prevalent in establishing secure connectivity in our digital society. Such computations handle sensitive information like encryption keys, which are usually very exposed during manipulation, resulting in a huge threat to the security of the sensitive information concealed in cryptographic components. In the field of embedded systems security, side-channel analysis is one of the most powerful techniques against cryptographic implementations. The main subject of this thesis is the measurable side-channel security of cryptographic implementations, particularly in the presence of random masking. Overall, this thesis consists of two topics. One is the leakage quantification of the most general form of masking equipped with the linear codes, so-called code-based masking; the other one is exploration of applying more generic information measures in a context of side-channel analysis. Two topics are inherently connected to each other in assessing and enhancing the practical security of cryptographic implementations .Regarding the former, we propose a unified coding-theoretic framework for measuring the information leakage in code-based masking. Specifically, our framework builds formal connections between coding properties and leakage metrics in side-channel analysis. Those formal connections enable us to push forward the quantitative evaluation on how the linear codes can affect the concrete security of all code-based masking schemes. Moreover, relying on our framework, we consolidate code-based masking by providing the optimal linear codes in the sense of maximizing the side-channel resistance of the corresponding masking scheme. Our framework is finally verified by attack-based evaluation, where the attacks utilize maximum-likelihood based distinguishers and are therefore optimal. Regarding the latter, we present a full spectrum of application of alpha-information, a generalization of (Shannon) mutual information, for assessing side-channel security. In this thesis, we propose to utilize a more general information-theoretic measure, namely alpha-information (alpha-information) of order alpha. The new measure also gives the upper bound on success rate and the lower bound on the number of measurements. More importantly, with proper choices of alpha, alpha-information provides very tight bounds, in particular, when alpha approaches to positive infinity, the bounds will be exact. As a matter of fact, maximum-likelihood based distinguishers will converge to the bounds. Therefore, we demonstrate how the two world, information-theoretic measures (bounds) and maximum-likelihood based side-channel attacks, are seamlessly connected in side-channel analysis .In summary, our study in this thesis pushes forward the evaluation and consolidation of side-channel security of cryptographic implementations. From a protection perspective, we provide a best-practice guideline for the application of code-based masking. From an evaluation perspective, the application of alpha-information enables practical evaluators and designers to have a more accurate (or even exact) estimation of concrete side-channel security level of their cryptographic chips
Houssain, Hilal. "Algorithmes cryptographiques à base de courbes elliptiques résistant aux attaques par analyse de consommation". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2012. http://tel.archives-ouvertes.fr/tel-00832795.
Pełny tekst źródłaMathieu-Mahias, Axel. "Sécurisation des implémentations d'algorithmes cryptographiques pour les systèmes embarqués". Electronic Thesis or Diss., université Paris-Saclay, 2021. http://www.theses.fr/2021UPASG095.
Pełny tekst źródłaEmbedded systems are ubiquitous and they have more and more applications. Most actual industrial fields rely on embedded systems for accomplishing specific tasks, sometimes highly sensitive. Currently, the deployment of embedded systems is even more increasing by the birth of the "Internet of Things", which is expected to revolutionize our digital world.An embedded system is an electronic and informatic system in control of a specific part of a larger system. Numerous constraints, in particular regarding its size, must be taken into account during its conception. Consequently, an embedded system is usually low cost, consume low power and has limited computational resources.For accomplishing its specific tasks, an embedded system collect, manipulate and exchange data that are usually sensitive. Moreover, such a system can often be directly accessible physically. This particularity can then be exploited by an unauthorized entity in order to control, extract or alter sensitive data manipulated by such systems.In this context, it is mandatory to develop well-suited security mechanisms. In particular, it is crucial to prevent direct physical access to the device but also to protect sensitive data manipulated or stored by the device.Cryptography is the science of secrets and offers numerous ways to mitigate the risks that face electronic devices. However, in such a context, some physical characteristics of the electronics of embedded systems vary during the execution of the implementations of cryptographic algorithms guaranteeing the security of information. In particular, the power consumption of a device or its electromagnetic radiations depend on the manipulated data as well as of the choices made for implementing the cryptographic algorithms. These physical characteristics can also be measured if physical access to the device is possible. The exploitation of these measurements has led to devastating attacks called "Side-Channel attacks". Mounting this kind of attacks enables to extract sensitive data stored or manipulated by an electronic device, usually without much effort.Special countermeasures have to be implemented to mitigate the security risks that face the implementations of cryptographic algorithms without deteriorating too much their performances in practice. Masking is a well-known solution, but its correct implementation requires a thorough analysis of algorithmic solutions it provides, especially in the context just described where devices have limited resources
Dugardin, Margaux. "Amélioration d'attaques par canaux auxiliaires sur la cryptographie asymétrique". Thesis, Paris, ENST, 2017. http://www.theses.fr/2017ENST0035/document.
Pełny tekst źródła: Since the 1990s, side channel attacks have challenged the security level of cryptographic algorithms on embedded devices. Indeed, each electronic component produces physical emanations, such as the electromagnetic radiation, the power consumption or the execution time. Besides, these emanations reveal some information on the internal state of the computation. A wise attacker can retrieve secret data in the embedded device using the analyzes of the involuntary “leakage”, that is side channel attacks. This thesis focuses on the security evaluation of asymmetric cryptographic algorithm such as RSA and ECC. In these algorithms, the main leakages are observed on the modular multiplication. This thesis presents two attacks targeting the modular multiplication in protected algorithms, and a formal demonstration of security level of a countermeasure named modular extension. A first attack is against scalar multiplication on elliptic curve implemented with a regular algorithm and scalar blinding. This attack uses a unique acquisition on the targeted device and few acquisitionson another similar device to retrieve the whole scalar. A horizontal leakage during the modular multiplication over large numbers allows to detect and correct easily an error bit in the scalar. A second attack exploits the final subtraction at the end of Montgomery modular multiplication. By studying the dependency of consecutive multiplications, we can exploit the information of presence or absence of final subtraction in order to defeat two protections : regular algorithm and blinding input values. Finally, we prove formally the security level of modular extension against first order fault attacks applied on elliptic curves cryptography
Dugardin, Margaux. "Amélioration d'attaques par canaux auxiliaires sur la cryptographie asymétrique". Electronic Thesis or Diss., Paris, ENST, 2017. http://www.theses.fr/2017ENST0035.
Pełny tekst źródła: Since the 1990s, side channel attacks have challenged the security level of cryptographic algorithms on embedded devices. Indeed, each electronic component produces physical emanations, such as the electromagnetic radiation, the power consumption or the execution time. Besides, these emanations reveal some information on the internal state of the computation. A wise attacker can retrieve secret data in the embedded device using the analyzes of the involuntary “leakage”, that is side channel attacks. This thesis focuses on the security evaluation of asymmetric cryptographic algorithm such as RSA and ECC. In these algorithms, the main leakages are observed on the modular multiplication. This thesis presents two attacks targeting the modular multiplication in protected algorithms, and a formal demonstration of security level of a countermeasure named modular extension. A first attack is against scalar multiplication on elliptic curve implemented with a regular algorithm and scalar blinding. This attack uses a unique acquisition on the targeted device and few acquisitionson another similar device to retrieve the whole scalar. A horizontal leakage during the modular multiplication over large numbers allows to detect and correct easily an error bit in the scalar. A second attack exploits the final subtraction at the end of Montgomery modular multiplication. By studying the dependency of consecutive multiplications, we can exploit the information of presence or absence of final subtraction in order to defeat two protections : regular algorithm and blinding input values. Finally, we prove formally the security level of modular extension against first order fault attacks applied on elliptic curves cryptography
Cagli, Eleonora. "Feature Extraction for Side-Channel Attacks". Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS295.
Pełny tekst źródłaCryptographic integrated circuits may be vulnerable to attacks based on the observation of information leakages conducted during the cryptographic algorithms' executions, the so-called Side-Channel Attacks. Nowadays the presence of several countermeasures may lead to the acquisition of signals which are at the same time highly noisy, forcing an attacker or a security evaluator to exploit statistical models, and highly multi-dimensional, letting hard the estimation of such models. In this thesis we study preprocessing techniques aiming at reducing the dimension of the measured data, and the more general issue of information extraction from highly multi-dimensional signals. The first works concern the application of classical linear feature extractors, such as Principal Component Analysis and Linear Discriminant Analysis. Then we analyse a non-linear generalisation of the latter extractor, obtained through the application of a « Kernel Trick », in order to let such preprocessing effective in presence of masking countermeasures. Finally, further generalising the extraction models, we explore the deep learning methodology, in order to reduce signal preprocessing and automatically extract sensitive information from rough signal. In particular, the application of the Convolutional Neural Network allows us to perform some attacks that remain effective in presence of signal desynchronisation
Houssain, Hilal. "Elliptic curve cryptography algorithms resistant against power analysis attacks on resource constrained devices". Thesis, Clermont-Ferrand 2, 2012. http://www.theses.fr/2012CLF22286/document.
Pełny tekst źródłaElliptic Curve Cryptosystems (ECC) have been adopted as a standardized Public Key Cryptosystems (PKC) by IEEE, ANSI, NIST, SEC and WTLS. In comparison to traditional PKC like RSA and ElGamal, ECC offer equivalent security with smaller key sizes, in less computation time, with lower power consumption, as well as memory and bandwidth savings. Therefore, ECC have become a vital technology, more popular and considered to be particularly suitable for implementation on resource constrained devices such as the Wireless Sensor Networks (WSN). Major problem with the sensor nodes in WSN as soon as it comes to cryptographic operations is their extreme constrained resources in terms of power, space, and time delay, which limit the sensor capability to handle the additional computations required by cryptographic operations. Moreover, the current ECC implementations in WSN are particularly vulnerable to Side Channel Analysis (SCA) attacks; in particularly to the Power Analysis Attacks (PAA), due to the lack of secure physical shielding, their deployment in remote regions and it is left unattended. Thus designers of ECC cryptoprocessors on WSN strive to introduce algorithms and architectures that are not only PAA resistant, but also efficient with no any extra cost in terms of power, time delay, and area. The contributions of this thesis to the domain of PAA aware elliptic curve cryptoprocessor for resource constrained devices are numerous. Firstly, we propose two robust and high efficient PAA aware elliptic curve cryptoprocessors architectures based on innovative algorithms for ECC core operation and envisioned at securing the elliptic curve cryptoprocessors against Simple Power Analysis (SPA) attacks on resource constrained devices such as the WSN. Secondly, we propose two additional architectures that are envisioned at securing the elliptic curve cryptoprocessors against Differential Power Analysis (DPA) attacks. Thirdly, a total of eight architectures which includes, in addition to the two SPA aware with the other two DPA awareproposed architectures, two more architectures derived from our DPA aware proposed once, along with two other similar PAA aware architectures. The eight proposed architectures are synthesized using Field Programmable Gate Array (FPGA) technology. Fourthly, the eight proposed architectures are analyzed and evaluated by comparing their performance results. In addition, a more advanced comparison, which is done on the cost complexity level (Area, Delay, and Power), provides a framework for the architecture designers to select the appropriate design. Our results show a significant advantage of our proposed architectures for cost complexity in comparison to the other latest proposed in the research field
Fernandes, Medeiros Stéphane. "Attaques par canaux auxiliaires: nouvelles attaques, contre-mesures et mises en oeuvre". Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209096.
Pełny tekst źródłaDoctorat en Sciences
info:eu-repo/semantics/nonPublished
Barthe, Lyonel. "Stratégies pour sécuriser les processeurs embarqués contre les attaques par canaux auxiliaires". Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20046/document.
Pełny tekst źródłaSide-channel attacks such as differential power analysis (DPA) and differential electromagnetic analysis (DEMA) pose a serious threat to the security of embedded systems. The aim of this thesis is to study the side-channel vulnerabilities of software cryptographic implementations in order to create a new class of processor. For that purpose, we start by identifying the different elements of embedded processors that can be exploited to reveal the secret information. Then, we introduce several strategies that seek a balance between performance and security to protect such architectures at the register transfer level (RTL). We also present the design and implementation details of a secure processor, the SecretBlaze-SCR. Finally, we evaluate the effectiveness of the proposed solutions against global and local electromagnetic analyses from experimental results obtained with a FPGA-based SecretBlaze-SCR. Through this case study, we show that a suitable combination of countermeasures significantly increases the side-channel resistance of processors while maintaining satisfactory performance for embedded systems
Vaquié, Bruno. "Contributions à la sécurité des circuits intégrés face aux attaques par canaux auxiliaires". Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20133/document.
Pełny tekst źródłaSide channel attacks such as power analysis attacks are a threat to the security of integrated circuits.They exploit the physical leakage of circuits during the cryptographic computations to retrieve the secret informations they contain. Many countermeasures, including hardware, have been proposed by the community in order to protect cryptosystems against such attacks. Despite their effectiveness, their major drawback is their significant additional cost in area, speed and consumption. This thesis aims at proposing low cost countermeasures able to reduce the leaks and offering a good compromise between security and costs. First we identify the main sources of leakage of a cryptographic system that integrates an iterative hardware architecture of a symetric algorithm. Then we propose several low cost countermeasures, which aim at reducing this leakage. Finally, we evaluate the robustness of our solutions against side channel attacks
Dosso, Fangan Yssouf. "Contribution de l'arithmétique des ordinateurs aux implémentations résistantes aux attaques par canaux auxiliaires". Electronic Thesis or Diss., Toulon, 2020. http://www.theses.fr/2020TOUL0007.
Pełny tekst źródłaThis thesis focuses on two currently unavoidable elements of public key cryptography, namely modular arithmetic over large integers and elliptic curve scalar multiplication (ECSM). For the first one, we are interested in the Adapted Modular Number System (AMNS), which was introduced by Bajard et al. in 2004. In this system of representation, the elements are polynomials. We show that this system allows to perform modular arithmetic efficiently. We also explain how AMNS can be used to randomize modular arithmetic, in order to protect cryptographic protocols implementations against some side channel attacks. For the ECSM, we discuss the use of Euclidean Addition Chains (EAC) in order to take advantage of the efficient point addition formula proposed by Meloni in 2007. The goal is to first generalize to any base point the use of EAC for ECSM; this is achieved through curves with one efficient endomorphism. Secondly, we propose an algorithm for scalar multiplication using EAC, which allows error detection that would be done by an attacker we detail
Geib, Sandrine. "Mécanismes de régulation des canaux calcium sensibles au potentiel par les sous-unités auxiliaires béta". Aix-Marseille 2, 2002. http://www.theses.fr/2002AIX20661.
Pełny tekst źródłaMartinelli, Jean. "Protection d'algorithmes de chiffrement par blocs contre les attaques par canaux auxiliaires d'ordre supérieur". Versailles-St Quentin en Yvelines, 2011. http://www.theses.fr/2011VERS0043.
Pełny tekst źródłaTraditionally, a cryptographic algorithm is estimated through its resistance to "logical" attacks. When this algorithm is implanted within a material device, physical leakage can be observed during the computation and can be analyzed by an attacker in order to mount "side channel" attacks. The most studied side channel attack is the differential power analysis (DPA). First order DPA is now well known and can be prevented by securely proven countermeasures. In 2008, some results are known for second order, but none for third order. The goal of this thesis is to propose a frame for k-th order DPA where k>1. We developed several masking schemes as alternatives to the classical ones in order to propose a better complexity-security ratio. These schemes make use of various mathematical operations such as field multiplication or matrix product and cryptographic tools as secret sharing and multi-party computation. We estimated the security of the proposed schemes following a methodology using both theoretical analysis and practical results. At last we proposed an evaluation of the action of the word size of a cryptographic algorithm upon its resistance against side channel attacks, with respect to the masking scheme implemented
Thillard, Adrian. "Contre-mesures aux attaques par canaux cachés et calcul multi-parti sécurisé". Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEE053/document.
Pełny tekst źródłaCryptosystems are present in a lot of everyday life devices, such as smart cards, smartphones, set-topboxes or passports. The security of these devices is threatened by side-channel attacks, where an attacker observes their physical behavior to learn information about the manipulated secrets. The evaluation of the resilience of products against such attacks is mandatory to ensure the robustness of the embedded cryptography. In this thesis, we exhibit a methodology to efficiently evaluate the success rate of side-channel attacks, without the need to actually perform them. In particular, we build upon a paper written by Rivainin 2009, and exhibit explicit formulaes allowing to accurately compute the success rate of high-order side-channel attacks. We compare this theoretical approach against practical experiments. This approach allows for a quick assessment of the probability of success of any attack based on an additive distinguisher. We then tackle the issue of countermeasures against side- channel attacks. To the best of our knowledge, we study for the first time since the seminal paper of Ishai, Sahai and Wagner in 2003 the issue of the amount of randomness in those countermeasures. We improve the state of the art constructions and show several constructions and bounds on the number of random bits needed to securely perform the multiplication of two bits. We provide specific constructions for practical orders of masking, and prove their security and optimality. Finally, we propose a protocolallowing for the private computation of a secure veto among an arbitrary large number of players, while using a constant number of random bits. Our construction also allows for the secure multiplication of any number of elements of a finite field
Rosa, Nicolas. "Rôle des sous-unités auxiliaires des canaux calciques Cav1 dans les lymphocytes Th2 : implications thérapeutiques dans l'asthme allergique". Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30359/document.
Pełny tekst źródłaCalcium channels include store-operated (ORAI) and voltage-gated (Cav) channels that are considered to be important for calcium entry in non-excitable and excitable cells, respectively. Voltage-gated calcium channels such as Cav1 are essential for excitable cell function, including neuronal transmission, muscle contraction or hormone secretion. However, numerous studies show that Cav1 channels are expressed in non-excitable cells as well, and are important for T cell effector functions. Cav1 channels are composed of the a1 subunit forming the ion pore and auxiliary subunits ß and a2δ. These subunits are important for the electric activity of the channel but also for its regulation, its stability and its expression at the plasma membrane in excitable cells. Our group clearly identified the a1 subunit of Cav1.2 and Cav1.3 channels as essential for the function of Th2 lymphocytes, a T cell subset responsible for allergic diseases. Pharmacological and genetic inhibition of these channels significantly reduces the expression of cytokines in mouse Th2 cells, but not in Th1 cells. The goal of my work was to understand whether the auxiliary subunits of Cav channels, particularly the ß subunit, are necessary for the function of Cav1 channels in Th2 lymphocytes that are not excitable cells. We used antisense oligonucleotides targeting all ß subunits to reduce the expression of ß1 and ß3, the two subunits expressed in Th2 lymphocytes. Transfection of murine and human Th2 with these oligonucleotides decreases TCR-dependent calcium influx and cytokine expression. In addition, the effect of the Cavß antisense oligonucleotides seems to result from the loss of expression of the a1 subunit, as similarly described in neurons. In addition, the use of shRNA specific to ß1 and ß3 in mouse Th2 shows a critical role the ß1 subunit in the functional response of Th2 lymphocytes. Finally, the Cavß antisense oligonucleotides reduce the airway inflammation in an allergic asthma model in mice, as well as a pharmacological inhibitor of a2δ subunits. This work has identified auxiliary subunits of Cav channels as new potential therapeutic targets in allergic diseases such as asthma
LEMAILLET, GUY. "Relations structure-fonction de canaux potassiques vegetaux : analyse fonctionnelle en systemes heterologues de canaux mutants". Paris, Institut national d'agronomie de Paris Grignon, 1997. http://www.theses.fr/1997INAP0046.
Pełny tekst źródłaReynaud, Léo. "Contributions à l’analyse de canaux auxiliaires sans connaissance des clairs et chiffrés, et à la recherche de S-boxes compactes". Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0107.
Pełny tekst źródłaCryptography is widely used nowadays, and side channel attacks are known threats. In order to develop suitable countermeasures, these attacks are constantly studied and improved. This document is part with this approach and studies joint distributions attacks which do not need the plaintext nor the ciphertext, contrary to classical attacks. First, new variants which improve this attack are proposed. They mainly consist in observing more or different intermediate variables, and adapt theoretical distributions accordingly. Then, a practical experiment is done on a microcontroller which validates the attack apart from simulations. Finally, several solutions that compromise masked implementations are proposed. They consist in using the fact that some masks are reused on several internal variables, ending in the quadrivariate attacks proposal. An other main theme about 8 bits S-boxes construction is explored in this document, and originated from the participation to the PACLIDO project which aims to develop a lightweight cryptography algorithm. The S-box is a critical component of cryptographic algorithms and acts to make them resilient to classical cryptanalysis. Unfortunately, this component is often costly in terms of logical gates. We propose two methods for searching compact 8 bit circuits composed of hybrid gates ANDXOR, and show some results close to the literature
Barbier, Johann. "Analyse de canaux de communication dans un contexte non coopératif". Phd thesis, Ecole Polytechnique X, 2007. http://pastel.archives-ouvertes.fr/pastel-00003711.
Pełny tekst źródłaTareen, Shahwali Khan. "Analyse moléculaire des canaux potassiques task dans l'aldostéronisme primaire humain". Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066056.
Pełny tekst źródłaHypertension is the leading cause of human mortality globally. Representing about a tenth of all patients, Primary Aldosteronism (PA) is the commonest identifiable cause of hypertension, and results from the autonomous production of aldosterone by the adrenal glands. The two principal sub-types are Bilateral Adrenal Hyperplasia (BAH), and Aldosterone Producing Adenoma (APA), which account for two-thirds and one-third of the cases respectively. The molecular etiology of primary aldosteronism has remained elusive until recently, when through an exome sequencing study, mutations in the potassium channel-coding gene KCNJ5 were found to cause PA in humans. These mutations were found in up to 40% of APAs, and only in a rare familial variety of BAH. A subsequent exome sequencing study identified mutations in ATPase famile genes in about 7% of APAs, bringing the total genetic yield to about 47%. The molecular pathology of more than half of APAs and of most BAHs remain unexplained. In mouse models, the genetic deletion of TASK-1 and TASK-3 potassium channels cause biochemical changes that resemble those seen in human PA. TASK 1 and TASK 3 are background ‘leak’ potassium channels, which by permitting the outward flow of K+ ions, polarise the adrenal glomerulosa cell membrane potential. The genetic removal of these channels therefore results in a marked depolarization of the glomerulosa cells, leading to their increased aldosterone secretory function, diagnosed as PA. In humans, the contribution of TASK-1 and TASK-3 channel dysfunction to PA has been negated by sequencing studies of the genes that code for these channels (KCNK3 and KCNK9 respectively). However, these studies have included only a small number of patients, motivating a comprehensive molecular analysis of the genes in a large patient cohort. To this end, we investigated commonly and rarely occuring genetic variation in, and expression of, KCNK 3 and KCNK9. Our Genome Wide Association Study (GWAS) showed no association of PA (either APA or BAH subtypes or both) with any single SNP at the genome-wide level of statistical significance. At sub genome-wide levels, however, SNPs of KCNK3 did associate, and the association signal strengthened when specific combinations of the SNPs were tested for association at a time. While no inherited or acquired DNA sequence variation in KCNK3 and KCNK9 have ever been detected in PA patients, on sequencing germline DNA in 825 PA cases, and 41 tumoral DNA samples, 14 different coding single nucleotide variants in KCNK3 and KCNK9 were found in the germline DNA only, of which 6 were non-synonymous, and 8 synonymous. However, on heterologous expression and electrophysiology, these did not affect channel function. No somatic sequence changes were found.Expression of KCNK3 and KCNK9 was investigated by in-situ hybridization in 6 control adrenal glands and 20 adrenals from patients with APA. In the control adrenal, the KCNK3 gene was highly expressed in all three layers of the adrenal cortex, while KCNK9 expression was barely detectable, and restricted to the zona glomerulosa. In APAs, KCNK3 expression was detected in a majority of patients, while KCNK9 expression was low and heterogeneous among samples. Strikingly, KCNK9 was highly expressed in the hyperplastic peritumoral zona glomerulosa, possibly due to a positive feed-back by high circulating aldosterone or low potassium levels on KCNK9 expression. Transcriptome profiling of 43 APA and 11 control adrenals revealed a slight, but significantly increased expression of KCNK3 in adenomas compared to controls that correlated positively with CYP11B2 expression. The quantitative changes of TASK1 expression observed in APAs may be secondary to a primary epigenetic phenomenon or be secondary to increased aldosterone production due to dysregulation of master transcription factors or upstream signaling cascades in the aldosterone biosynthetic pathway
Tareen, Shahwali Khan. "Analyse moléculaire des canaux potassiques task dans l'aldostéronisme primaire humain". Electronic Thesis or Diss., Paris 6, 2014. http://www.theses.fr/2014PA066056.
Pełny tekst źródłaHypertension is the leading cause of human mortality globally. Representing about a tenth of all patients, Primary Aldosteronism (PA) is the commonest identifiable cause of hypertension, and results from the autonomous production of aldosterone by the adrenal glands. The two principal sub-types are Bilateral Adrenal Hyperplasia (BAH), and Aldosterone Producing Adenoma (APA), which account for two-thirds and one-third of the cases respectively. The molecular etiology of primary aldosteronism has remained elusive until recently, when through an exome sequencing study, mutations in the potassium channel-coding gene KCNJ5 were found to cause PA in humans. These mutations were found in up to 40% of APAs, and only in a rare familial variety of BAH. A subsequent exome sequencing study identified mutations in ATPase famile genes in about 7% of APAs, bringing the total genetic yield to about 47%. The molecular pathology of more than half of APAs and of most BAHs remain unexplained. In mouse models, the genetic deletion of TASK-1 and TASK-3 potassium channels cause biochemical changes that resemble those seen in human PA. TASK 1 and TASK 3 are background ‘leak’ potassium channels, which by permitting the outward flow of K+ ions, polarise the adrenal glomerulosa cell membrane potential. The genetic removal of these channels therefore results in a marked depolarization of the glomerulosa cells, leading to their increased aldosterone secretory function, diagnosed as PA. In humans, the contribution of TASK-1 and TASK-3 channel dysfunction to PA has been negated by sequencing studies of the genes that code for these channels (KCNK3 and KCNK9 respectively). However, these studies have included only a small number of patients, motivating a comprehensive molecular analysis of the genes in a large patient cohort. To this end, we investigated commonly and rarely occuring genetic variation in, and expression of, KCNK 3 and KCNK9. Our Genome Wide Association Study (GWAS) showed no association of PA (either APA or BAH subtypes or both) with any single SNP at the genome-wide level of statistical significance. At sub genome-wide levels, however, SNPs of KCNK3 did associate, and the association signal strengthened when specific combinations of the SNPs were tested for association at a time. While no inherited or acquired DNA sequence variation in KCNK3 and KCNK9 have ever been detected in PA patients, on sequencing germline DNA in 825 PA cases, and 41 tumoral DNA samples, 14 different coding single nucleotide variants in KCNK3 and KCNK9 were found in the germline DNA only, of which 6 were non-synonymous, and 8 synonymous. However, on heterologous expression and electrophysiology, these did not affect channel function. No somatic sequence changes were found.Expression of KCNK3 and KCNK9 was investigated by in-situ hybridization in 6 control adrenal glands and 20 adrenals from patients with APA. In the control adrenal, the KCNK3 gene was highly expressed in all three layers of the adrenal cortex, while KCNK9 expression was barely detectable, and restricted to the zona glomerulosa. In APAs, KCNK3 expression was detected in a majority of patients, while KCNK9 expression was low and heterogeneous among samples. Strikingly, KCNK9 was highly expressed in the hyperplastic peritumoral zona glomerulosa, possibly due to a positive feed-back by high circulating aldosterone or low potassium levels on KCNK9 expression. Transcriptome profiling of 43 APA and 11 control adrenals revealed a slight, but significantly increased expression of KCNK3 in adenomas compared to controls that correlated positively with CYP11B2 expression. The quantitative changes of TASK1 expression observed in APAs may be secondary to a primary epigenetic phenomenon or be secondary to increased aldosterone production due to dysregulation of master transcription factors or upstream signaling cascades in the aldosterone biosynthetic pathway
Battistello, Alberto. "On the security of embedded systems against physical attacks". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLV047/document.
Pełny tekst źródłaThe subject of this thesis is the security analysis of cryptographic implementations. The need for secure communications has always been a primary need for diplomatic and strategic communications. Cryptography has always been used to answer this need and cryptanalysis have often been solicited to reveal the content of adversaries secret communications. The advent of the computer era caused a shift in the communication paradigms and nowadays the need for secure communications extends to most of commercial and economical exchanges. Modern cryptography provides solutions to achieve such new security goals but also open the way to a number of new threats. It is the case of fault and side-channel-attacks, which today represents the most dangerous threats for embedded cryptographic implementations. This thesis resumes the work of research done during the last years as a security engineer at Oberthur Technologies. Most of the results obtained have been published as research papers [9,13-17] or patents [1-6]. The security research goals of companies around the world working in the embedded domain are twofold. The security engineer has to demonstrate the ability to correctly evaluate the security of algorithms and to highlight possible threats that the product may incur during its lifetime. Furthermore it is desirable to discover new techniques that may provide advantages against competitors. It is in this context that we present our work.This manuscript is divided into four main chapters.The first chapter presents an introduction to various mathematical and computational aspects of cryptography and information theory. We also provide an introduction to the main aspects of the architecture of secure micro-controllers.Afterwards the second chapter introduces the notion of fault attacks and presents some known attack and countermeasure [15-17]. We then detail our work on asymmetric and symmetric infective fault countermeasures as long as on elliptic curves fault attacks [13].The third chapter discusses about side-channels, providing a brief introduction to the subject and to well-known side-channel attacks and countermeasures. We then present two new attacks on implementations that have been considered secure against side channels [9,14]. Afterwards we discuss our combined attack which breaks a state-of-the-art secure implementation [10].Finally, the fourth chapter concludes this works and presents some perspectives for further research.During our investigations we have also found many countermeasures that can be used to thwart attacks. These countermeasures have been mainly published in the form of patents [1-6]. Where possible some of them are presented along with the attack they are conceived to thwart
Asnagli, Hélène. "Analyse des paramètres impliqués dans la différenciation fonctionnelle des lymphocytes T murins". Aix-Marseille 2, 1998. http://www.theses.fr/1998AIX22027.
Pełny tekst źródłaGaugler, Béatrice. "Analyse de l'induction et de la régulation des réponses auxiliaires et cytolytiques des lymphocytes T". Aix-Marseille 2, 1992. http://www.theses.fr/1992AIX22078.
Pełny tekst źródłaMasgana, Delphine. "Injection de fautes et de logiciels sur les implémentations cryptographiques". Paris 7, 2012. http://www.theses.fr/2012PA077215.
Pełny tekst źródłaThe cryptography is very widespread inside smartcards or secure devices. These embedded cryptoSystems are proved theoretically secure. Nevertheless, they infère in far or near environment. So active perturbations, named fault analysis, or passive eavesdropping, called side-channel analysis, constitute real threats against hardware and software implementations. This thesis dealts with fault and software injections on cryptographie protocols. The fault analysis and side-channnel analysis give some more information on hardware and software implementations. The internai state of cryptographic computations, secret or private keys or private algorithms are all potential targets of this kind of analysis. In this thesis, a statistical analysis based on fault attack on the carry of Schnorr scheme operations gives access to private key in asymmetric signature or ciphering. Then, code injection in order to monitor memory cache of computer allows one to retrieve secret permutation table for stream cipher RC4, due to timing analysis on cache lines. Then, two differential analysis on internai rounds of AES enable to obtain secret key for the three different AES variants. Finally, a new consequence of fault model, which bypasses one instruction, allows one to take over a host. It is proved that it is important to protect cryptographic implémentations with proper countermeasures against fault analysis and side-channel analysis
Patenaude, François. "Modélisation et détection par analyse propre pour les canaux multivoies avec évanouissements". Thesis, University of Ottawa (Canada), 1996. http://hdl.handle.net/10393/10253.
Pełny tekst źródłaDrujont, Lucile. "Étude de nouveaux acteurs de l'immunité de type 17 à travers l'exploration du rôle des canaux ioniques TMEM176A et B dans les cellules RORγt+". Nantes, 2016. https://archive.bu.univ-nantes.fr/pollux/show/show?id=36471303-ef4e-453c-94a1-59fb808e17a9.
Pełny tekst źródłaThe nuclear hormone receptor RORγt is the key transcription factor that orchestrates the differentiation of Th17 cells but also defines γƠT17 cells and group 3 Innate Lymphoid Cells (ILC3s). We identified TMEM176B, a fourspan transmembrane protein that interacts with its structurally identical homolog protein TMEM176A. Electrophysiological experiments revealed that TMEM176A and B function as cation channels and can heteromerize to exert their function. Strikingy, these two homologs were found among the few direct targets of RORγt. We show that both genes are highly expressed in in vitro-generated mouse Th17 cells compared to Th1, Th2 or iTregs. We also observed that human Th17 cells strongly express TMEM176A and B mRNA, correlating with the level of RORC or IL17A. We further demonstrate that Tmem176a and b are highly expressed in ILC3s and γƠT17 cells. We thus hypothesized that these genes could play a crucial role in the development of a variety of autoimmune diseases dependent on RORγt+ cells. In this regard, Tmem176bdeficient mice were partially but significantly protected from psoriasis-like lesions when compared to control mice. These results suggest that the deletion of both genes may be required to clearly elucidate their role. We have successfully generated a double KO mouse and started to assess the impact of this double deficiency in the steady states as well as in models of inflammation. In parallel, we found that TMEM176A and B protein localizations are strongly linked to the Golgi apparatus, thus highlighting novel potential mechanisms of post-translational modifications or intracellular trafficking in which these cation channels could be involved. We believe that the study of TMEM176A and B will help decipher novel specific pathways of the RORYt+ cell biology that could be therapeutically manipulated
Gorgoglione, Matteo. "Analyse et construction de codes LDPC non-binaires pour des canaux à évanouissement". Phd thesis, Université de Cergy Pontoise, 2012. http://tel.archives-ouvertes.fr/tel-00778170.
Pełny tekst źródłaGorgolione, Matteo. "Analyse et construction de codes LDPC non-binaires pour des canaux à évanouissement". Phd thesis, Université de Cergy Pontoise, 2012. http://tel.archives-ouvertes.fr/tel-00819415.
Pełny tekst źródłaNajeme, Abdelatif. "Analyse globale par approximation polynomiale des écoulements dans les conduites et les canaux". Toulouse 3, 1992. http://www.theses.fr/1992TOU30028.
Pełny tekst źródłaGorgoglione, Matteo. "Analyse et construction de codes LDPC non-binaires pour des canaux à evanouissement". Thesis, Cergy-Pontoise, 2012. http://www.theses.fr/2012CERG0578/document.
Pełny tekst źródłaOver the last 15 years, spectacular advances in the analysis and design of graph-basedcodes and iterative decoding techniques paved the way for the development of error correctionsystems operating very close to the theoretical Shannon limit. A prominent rolehas been played by the class of Low Density Parity Check (LDPC) codes, introduced inthe early 60's by Gallager's and described latter in terms of sparse bipartite graphs. In theearly 2000's, LDPC codes were shown to be capacity approaching codes for a wide rangeof channel models, which motivated the increased interest of the scientific community andsupported the rapid transfer of this technology to the industrial sector. Over the past fewyears there has been an increased interest in non-binary LDPC codes due to their enhancedcorrection capacity. Although Gallager already proposed in his seminal work the use ofnon-binary alphabets (by using modular arithmetic), non-binary LDPC codes defined overfinite fields have only been investigated starting with the late 90's. They have been provento provide better performance than their binary counterparts when the block-length issmall to moderate, or when the symbols sent through channel are not binary, which is thecase for high-order modulations or for multiple-antennas channels. However, the performancegain comes at a non-negligible cost in the decoding complexity, which may prohibitthe use of non-binary LDPC codes in practical systems, especially when the price to payin decoding complexity is too high for the performance gain that one can get.This thesis addresses the analysis and design of non-binary LDPC codes for fadingchannels. The main goal is to demonstrate that besides the gain in the decoding performance,the use of non-binary LDPC codes can bring additional benefits that may offsetthe extra cost in decoding complexity. Flexibility and diversity are the two benefitsthat we demonstrate in this thesis. The exibility is the capacity of a coding system toaccommodate multiple coding rates through the use of a unique encoder/decoder pair. Thediversity of a coding system relates to its capacity to fully exploit the communicationchannel's heterogeneity.The first contribution of the thesis is the development of a Density Evolution approximationmethod, based on the Monte-Carlo simulation of an infinite code. We showthat the proposed method provides accurate and precise estimates of non-binary ensemblethresholds, and makes possible the optimization of non-binary codes for a wide range ofapplications and channel models.The second contribution of the thesis consists of the analysis and design of flexiblecoding schemes through the use of puncturing. We show that the non-binary LDPCcodes are more robust to puncturing than their binary counterparts, thanks to the factthat non-binary symbol-nodes can be only partially punctured. For regular codes, we showthat the design of puncturing patterns must respect different rules depending on whetherthe symbol-nodes are of degree 2 or higher. For irregular codes we propose an optimizationprocedure and we present optimized puncturing distributions for non-binary LDPC codes,iiiwhich exhibit a gap to capacity between 0.2 and 0.5dB , for punctured rates varying from0.5 to 0.9.The third contribution investigates the non-binary LDPC codes transmitted over aRayleigh (fast) fading channel, in which different modulated symbols are affected by differentfading factors. In case of one-to-one correspondence between modulated and codedsymbols, deep fading can make some coded symbols totally unrecoverable, leading to apoor system performance. In order to avoid this phenomenon, binary diversity can beexploited by using a bit-interleaver module placed between the encoder and the modulator.We propose an optimized interleaving algorithm, inspired from the Progressive Edge-Growth (PEG) method, which ensures maximum girth of th
Juvin, Véronique. "Caractérisation pharmacologique du canal TRPV2 recombinant et analyse des fonctions de la protéine endogène dans les cellules immunitaires". Montpellier 1, 2007. http://www.theses.fr/2007MON1T016.
Pełny tekst źródłaEl, Fatni Abdelaziz. "Modélisation, analyse et conception de protocoles MAC multi-canaux dans les réseaux sans fil". Thesis, Toulouse 2, 2013. http://www.theses.fr/2013TOU20033.
Pełny tekst źródłaThe use of multi-channel communications in MAC protocols (multi-channel MAC) for wireless networks can significantly improve the network throughput compared with single channel MAC protocols since concurrent transmissions can take place simultaneously on distinct non-overlapping channels without interfering. However, due to the multi-channel environment, a novel issue must be addressed in MAC protocols, which is called "the channel assignment mechanism" in order to coordinate the channels access. The role of this mechanism is to enable nodes to agree on which channel should be used and when for data transmission in a distributed way. The absence of this mechanism or a bad coordination of the channel usage can incur the opposite effect to that intended. Thus, the efficiency of a multi-channel MAC protocol depends strictly on the efficiency of the channel assignment mechanism, which also must provide the guarantees necessary to the good behavior of the multi-channel communications. In this thesis, we focus on the modeling, analysis, and design of new multi-channel MAC protocols in wireless networks. Firstly, we focus on the formal specification and verification of fundamental properties inherent to the activities of the channel assignment and its impact on the data transfer for the main multi-channel MAC approaches proposed in the literature. Secondly, we aim to propose, model and analyze formally two new multichannel MAC protocols, resulting from the qualitative analysis conducted. Finally, a quantitative and comparative study is conducted to analyze the performance of the proposed protocols in terms of the throughput and the impact of the switching time between channels
Mesquita, Daniel Gomes. "Architectures Reconfigurables et Cryptographie : une analyse de robustesse face aux attaques par canaux cachés". Montpellier 2, 2006. http://www.theses.fr/2006MON20097.
Pełny tekst źródłaThis work addresses the reconfigurable architectures for cryptographic applications theme, emphasizing the robustness issue. Some mathematical background is reviewed, as well the state of art of reconfigurable architectures. Side channel attacks, specially the DPA and SPA attacks, are studied. As consequence, algorithmic, hardware and architectural countermeasures are proposed. A new parallel reconfigurable architecture is proposed to implement the Leak Resistant Arithmetic. This new architecture outperforms most of state of art circuits for modular exponentiation, but the main feature of this architecture is the robustness against DPA attacks
Neyton, Jacques. "Propriétés des canaux des jonctions Gap et leur modulation par les neurotransmetteurs : analyse électrophysiologique". Paris 6, 1986. http://www.theses.fr/1986PA066298.
Pełny tekst źródłaNeyton, Jacques. "Propriétés des canaux des jonctions gap et leur modulation par les neurotransmetteurs analyse électrophysiologique". Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37600012c.
Pełny tekst źródłaFajloun, Ziad. "Toxines courtes de scorpion actives sur les canaux K+ et Ca2+ : synthèse chimique, caractérisation pharmacologique et étude des relations structure-activité à l'aide d'analogues structuraux". Aix-Marseille 2, 2001. http://theses.univ-amu.fr.lama.univ-amu.fr/2001AIX20672.pdf.
Pełny tekst źródłaToubbe, Bébé. "Etalonnage en vol sur le glitter des canaux polarisés de l'instrument POLDER : analyse d'images aéroportées". Lille 1, 1996. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1996/50376-1996-85.pdf.
Pełny tekst źródłaEl, Aabid Moulay Abdelaziz. "Attaques par canaux cachés : expérimentations avancées sur les attaques template". Paris 8, 2011. http://www.theses.fr/2011PA083394.
Pełny tekst źródłaIn 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 \emph{template attack}, and we provide some practical improvements. The analyse consists in a case-study based on side-channel measurements acquired experimentally from a hardwired cryptographic accelerator. The principal component analysis (PCA) is used to represent the \emph{templates} in some dimensions, and we give a physical interpretation of the \emph{templates} eigenvalues and eigenvectors. We introduce a method based on the thresholding of leakage data to accelerate the profiling or the matching stages. In this context, there is an opportunity to study how to best combine many attacks with many leakages from different sources or using different samples from a single source. That brings some concrete answers to the attack combination problem. Also we focus on identifying the problems that arise when there is a discrepancy between the \emph{templates} and the traces to match : the traces can be desynchronized and the amplitudes can be scaled differently. Then we suggest two remedies to cure the \emph{template} mismatches. We show that SCAs when performed with a multi-resolution analysis are much better than considering only the time or the frequency resolution. Actually, the gain in number of traces needed to recover the secret key is relatively considerable with repect to an ordinary attack
Bendinelli, Marion. "Etude des auxiliaires modaux et des semi-modaux dans les débats présidentiels américains (1960-2008) : analyse qualitative et quantitative". Nice, 2012. http://www.theses.fr/2012NICE2017.
Pełny tekst źródłaThis dissertation consists in the study of modals and semi-modals in a corpus of American presidential debates (1960-2008). Our aim is to characterize their use with respect to issues of power and influence. On the one hand, the theoretical framework borrows from various fields of linguistic analysis, namely enunciation, pragmatics and discourse analysis; the latter helps define notions such as persuasive communication, manipulation and influence strategies. Besides, we suggest that the modals and some semi-modals can activate dialogic echoes and serve as evidential markers. On the other hand, the study relies on a computer-based discourse analysis methodology, namely logometry. Considered as a valuable heuristic approach, it runs statistical measures on linguistic data – be it tokens, lemmas or parts of speech – so as to provide the analyst with frequency lists and cooccurrence networks, among other functionalities. Logometry also offers a bottom-up as well as a top-down approach to corpus scrutiny. The results help identify three enunciative strategies depending on the level of commitment of the utterer with his epistemic or non-epistemic judgements. Also, they determine the existence of several types of discourses that are considered in the light of various issues: speech practice evolution, ideological positioning, rhetorical identity of political parties, candidates’ campaign strategies. As far as the modals and semi-modals CAN, MUST, HAVE TO, HAVE GOT TO, NEED TO and OUGHT TO are concerned, a close examination of their contexts of use shows that they reflect different strategies of presentation of the self, of others, of the audience and of the factual context
Jauvart, Damien. "Sécurisation des algorithmes de couplages contre les attaques physiques". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLV059/document.
Pełny tekst źródłaThis thesis focuses on the resistance of Pairing implementations againstside channel attacks. Pairings have been studied as a cryptographic tool for the pastfifteen years and have been of a growing interest lately. On one hand, Pairings allowthe implementation of innovative protocols such as identity based encryption, attributebased encryption or one round tripartite exchange to address the evolving needs ofinformation systems. On the other hand, the implementation of the pairings algorithmshave become more efficient, allowing their integration into embedded systems.Like for most cryptographic algorithms, side channel attack schemes have beenproposed against Pairing implementations. However most of the schemes describedin the literature so far have had very little validation in practice. In this thesis, westudy the practical feasibility of such attacks by proposing a technique for optimizingcorrelation power analysis on long precision numbers. We hence improve by a factorof 10 the number of side-channel leakage traces needed to recover a 256-bit secret keycompared to what is, to our best knowledge, one of the rare practical implementationsof side channel attacks published. We also propose a horizontal attack, which allow usto attack the twisted Ate pairing using a single trace.In the same way, countermeasures have been proposed to thwart side channel attacks,without any theoretical or practical validation of the efficiency of such countermeasures.We here focus on one of those countermeasures based on coordinatesrandomization and show how a collision attack can be implemented against this countermeasure.As a result, we describe how this countermeasure would have to be implementedto efficiently protect Pairing implementations against side channel attacks.The latter studies raise serious questions about the validation of countermeasures whenintegrated into complex cryptographic schemes like Pairings