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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Caractérisation et utilisation du rayonnement électromagnétique pour l'attaque de composants cryptographiques / Characterization and use of the EM radiation to enhance side channel attacks

Meynard, Olivier 18 January 2012 (has links)
Caractérisation et Utilisation du Rayonnement Electromagnétique pour l'attaque de composants cryptographiques. Actuellement les algorithmes mathématiques de cryptographie sont de plus en plus sûrs et réputés incassables. Cependant, leurs implémentations sur des composants cryptographiques les rend vulnérables aux attaques physiques (matérielles ou logicielles) par canaux auxiliaires SCA (Side Channel Analysis). Dans cette thèse nous développons de façon plus précise l'étude des rayonnements électromagnétiques et leur caractérisation dans le domaine fréquentiel afin d'améliorer les attaques EMA à distance. Nous proposons différentes méthodes d'amélioration de ces attaques notamment en combinant des échantillons, afin de limiter la dégradation du modèle de fuite due à un faible rapport signal / bruit. Ensuite nous montrerons les limites des ces attaques avant de proposer des méthodes d'analyse fréquentielle, pour réduire la bande de fréquence d'analyse et améliorer la qualité du signal porteur d'information. Enfin, nous verrons que des méthodes utilisées en compatibilité électromagnétique peuvent être mises en place pour réaliser des attaques en fautes sur des composants cryptographiques. / Nowadays the mathematical algorithms for cryptography are becoming safer and deemed unbreakable from a mathematical point of view. So the confidence in cryptographic algorithms is increasing and the design of mathematical cryptographic algorithms remains definitively robust. However, the hardware implementation of cryptographic components are still vulnerable to physical attacks. Side Channel Analysis (SCA) is a threat for crypto systems as they can be used to recover secret key. These unintentional physical emanations can be analysed in a view to derive some sensitive information from them. In this thesis we conduct a more precise study of electromagnetic radiation and their characterization in the frequency domain to improve the EMA attacks at distance. We propose a method by combining time samples to improve these attacks, in order to limit the degradation of the leakage model due to low signal to noise ratio. Next we show the limits of the attack before proposing methods of frequency analysis, to focus the analysis on a wide band of frequencies and improve the quality of the signal carrying information. Finally we see that some methods used in electromagnetic compatibility and more precisely to evaluate susceptibility of electronic device. These techniques can be employed to perform fault attack and disrupt cryptographic component.
2

MCNP-modell för beräkning av neutrondos och DPA på reaktortanken vid Ringhals 2

Dalborg, Erik January 2013 (has links)
In this report an MCNP (Monte Carlo N-Particle) model is described for the reactor vessel at Ringhals 2. The model is validated against the specific activity in neutron dosimeters, extracted in 1977, 1984 and 1994. The validation showed that the calculations of the model are within the requirements of a maximum of 20 percent uncertainty for every neutron dosimeter except one, extracted after the first cycle. The uncertainty of this cycle was mostly due to the operation data rather than to the MCNP model. The model has been used to investigate various questions concerning radiation damage. The reliability of the traditional measure of radiation damage, fast neutron flux (En > 1MeV) has been evaluated.  This has been done by taking the ratio for this and another measure of radiation damage, DPA (Displacement Per Atom), for various positions and layers. The results show good reliability, except for at the outer layers of the vessel wall, where the traditional measure underestimates the radiation damage. Inspections are carried out in connection with the change of fuel to investigate any possible cracking on the internal structures of the reactor vessel.  New data on local differences in the radiation of these have therefore been calculated for future evaluations.  This is in order to be able to focus the inspections mainly on those internal parts that are exposed to the highest dose of radiation. An estimation of the neutron dose after 40, 50 and 60 years of operation has been calculated for the surface of the reactor vessel that is being exposed to the highest neutron flux. The result confirms earlier appreciation that the radiation damage to the reactor vessel is not a limiting factor for the future operation of Ringhals 2. The report also presents which surface of the vessel wall that has been exposed to a neutron dose of 1017 n/cm2 for neutrons with En > 1 MeV.
3

Estudo espectroscópico de complexos de íons lantanídeos com ligantes derivados de ácidos dicarboxílicos

Pereira de Lima, Patrícia January 2003 (has links)
Made available in DSpace on 2014-06-12T23:01:37Z (GMT). No. of bitstreams: 2 arquivo9187_1.pdf: 1228710 bytes, checksum: 909ead0a3ef880bbba1d9d04dc439cfe (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2003 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Neste trabalho foram sintetizados nove compostos de coordenação de íons lantanídeos (Ln = Eu3+, Tb3+ e Gd3+) com os ligantes: ácido dipicolínico (DPA), ácido quelidâmico (DAMIC) e ácido quelidônico (DONIC). Os complexos apresentam fórmulas gerais: Na3Ln(DPA)3⋅nH2O, Ln2(DONIC)3⋅7H2O e Ln2(DAMIC)⋅nH2O. Foram obtidos na forma de pó, tendo sido caracterizados por: determinação do ponto de fusão, análise elementar, espectroscopia de absorção nas regiões UV-visível e infravermelho e espectroscopia de emissão. Os resultados são consistentes com as fórmulas apresentadas acima. Através dos espectros de emissão do íon Eu3+ foi possível identificar que este íon encontra-se num ambiente de simetria baixa e que há evidência de apenas uma espécie emissora. Foram determinadas as taxas não-radiativas 4f-4f para os complexos de Eu3+ através de dados obtidos dos espectros de emissão e das medidas de decaimento dos estados excitados realizadas a temperatura ambiente e a 77 K. Observou-se que a taxa não-radiativa para o complexo Eu2(DONIC)3⋅7H2O era bastante elevada, comparando com os outros dois complexos de Eu3+. Isto foi explicado através da ressonância envolvendo quatro fônons, a qual pôde ser avaliada pelos espectros de infravermelho dos complexos do íon Eu3+ de acordo as bandas referentes aos modos vibracionais da água. O rendimento quântico de emissão experimental foi determinado usando-se o salicilato de sódio como padrão. O complexo Na3Tb(DPA)3⋅9H2O apresentou maior rendimento quântico (42,2%), e o complexo Na3Eu(DPA)3⋅6H2O apresentou o menor rendimento quântico (6,3%). Foi determinada teoricamente a geometria do estado fundamental do complexo [Eu(DPA)3]3- usando-se o modelo Sparkle. Após a determinação da geometria do estado fundamental desse complexo foram calculados os níveis eletrônicos singletos (importantes na obtenção do espectro eletrônico) e tripletos (importantes no estudo de possíveis mecanismos de transferência de energia). Com isso, foram calculados os parâmetros de intensidades de Judd-Ofelt, as taxas de transferência de energia e rendimento quântico teórico para o complexo [Eu(DPA)3]3-
4

A New Method for Studying Photon Upconversion

Miller, Jason Wayne 17 August 2013 (has links)
Upconversion studies typically use a laser as the source of low-energy photons. A lower cost, lower power, and fully tunable system was used here. The Fluoromax-4 spectrofluorometer incorporates a 150-W xenon lamp and illuminates a 1 cm3 volume in a standard cuvette. The 1 cm x 1cm excitation beam was reduced to 1 mm x 1 mm, increasing the power density by 100. The cuvette was mounted upon a translation stage so that the excitation beam could skim the inside surface of the cuvette. This minimized self-absorption of the output. Finally, an optical filter was included between the excitation monochromator and the cuvette to ensure that the solution was not exposed to undesired wavelengths. The instrument was tested with a known sensitizer/emitter system and upconversion was detected. Subsequently, a new pair of compounds was studied but the [Ru(deab)3]2+/BPEA solution did not exhibit upconversion in the modified instrument.
5

Sécurité cryptographique par la conception spécifique de circuits intégrés.

Germain, Fabien 23 June 2006 (has links) (PDF)
L'analyse différentielle de consommation (notée DPA pour Differential Power Analysis) est une puissante attaque non intrusive par canal auxilliaire dont l'objectif est de retrouver des informations secrètes contenues dans des circuits intégrés en exploitant la consommation globale. Des clés de chiffrement peuvent alors être découvertes pendant l'exécution d'algorithmes cryptographiques. L'objet de cette thèse est de proposer une contre-mesure véritablement efficace basée sur la conception de portes logiques intrinsèquement résistantes à la DPA indépendamment des états logiques et électriques passés, présents et futurs. Il est alors théoriquement possible de concevoir des circuits intégrés résistants à l'attaque DPA. La contre-mesure proposée repose sur des bases microélectroniques précises qui permettent d'expliciter les sources de la DPA. La solution s'appuie sur la conception CMOS (Complementary Metal Oxide Silicon) de circuits intégrés réalisant des algorithmes cryptographiques tels que l'AES (Advanced Encryption Standard).
6

Synthesis of Sulfamide Analogues of DPA in Anti-TB Drug Development

Liu, Fang January 2011 (has links)
In 2009, approximately 1.7 million people died of tuberculosis. The emergence of drug-resistant strains of Mycobacterium tuberculosis (M. tuberculosis) has created an urgent demand for the development of new anti-tuberculosis (anti-TB) drugs and treatments. M. tuberculosis, the causative agent, has a protective complex cell wall structure that is essential for its survival. One of the major building blocks of the cell wall structure is an arabinofuranosyl polysaccharide called arabinan. Since arabinan is not present in mammals, it has become a promising target for anti-TB drug development. The arabinan component is biosynthesized by a family of arabinofuranosyltransferases (araTs) using the substrate decaprenolphosphoarabinose (DPA) as the donor of arabinose. This project targets the biosynthesis of arabinan by synthesizing analogues of DPA as potential inhibitors of araTs. A sulfamide moiety was chosen as an isosteric replacement of the phosphate group of DPA. To mimic the polyprenyl chain of DPA, a series of alkyl chains of varying length and a triethylene glycol (TEG) derived chain were used.
7

Caractérisation et utilisation du rayonnement électromagnétique pour l'attaque de composants cryptographiques

Meynard, Olivier 18 January 2012 (has links) (PDF)
Caractérisation et Utilisation du Rayonnement Electromagnétique pour l'attaque de composants cryptographiques. Actuellement les algorithmes mathématiques de cryptographie sont de plus en plus sûrs et réputés incassables. Cependant, leurs implémentations sur des composants cryptographiques les rend vulnérables aux attaques physiques (matérielles ou logicielles) par canaux auxiliaires SCA (Side Channel Analysis). Dans cette thèse nous développons de façon plus précise l'étude des rayonnements électromagnétiques et leur caractérisation dans le domaine fréquentiel afin d'améliorer les attaques EMA à distance. Nous proposons différentes méthodes d'amélioration de ces attaques notamment en combinant des échantillons, afin de limiter la dégradation du modèle de fuite due à un faible rapport signal / bruit. Ensuite nous montrerons les limites des ces attaques avant de proposer des méthodes d'analyse fréquentielle, pour réduire la bande de fréquence d'analyse et améliorer la qualité du signal porteur d'information. Enfin, nous verrons que des méthodes utilisées en compatibilité électromagnétique peuvent être mises en place pour réaliser des attaques en fautes sur des composants cryptographiques.
8

Low Power Photoluminescence and Photochemical Upconversion

Islangulov, Radiy Rashitovich 02 November 2006 (has links)
No description available.
9

An Investigation of Differential Power Analysis Attacks on FPGA-based Encryption Systems

McDaniel, Larry T. III 22 July 2003 (has links)
Hardware devices implementing cryptographic algorithms are finding their way into many applications. As this happens, the ability to keep the data being processed or stored on the device secure grows more important. Power analysis attacks involve cryptographic hardware leaking information during encryption because power consumption is correlated to the key used for encryption. Power analysis attacks have proven successful against public and private key cryptosystems in a variety of form factors. The majority of the countermeasures that have been proposed for this attack are intended for software implementations on a microcontroller. This project focuses on the development of a VHDL tool for investigating power analysis attacks on FPGAs and exploring countermeasures that might be used. The tool developed here counted the transitions of CLB output signals to estimate power and was used to explore the impact of possible gate-level countermeasures to differential power analysis. Using this tool, it was found that only a few nodes in the circuit have a high correlation to bits of the key. This means that modifying only a small portion of the circuit could dramatically increase the difficulty of mounting a differential power analysis attack on the hardware. Further investigation of the correlation between CLB outputs and the key showed that a tradeoff exists between the amount of space required for decorrelation versus the amount of decorrelation that is desired, allowing a designer to determine the amount of correlation that can be removed for available space. Filtering of glitches on CLB output signals slightly reduced the amount of correlation each CLB had. Finally, a decorrelation circuit was proposed and shown capable of decorrelating flip-flop outputs of a CLB, which account for less than 10% of the CLB outputs signals. / Master of Science
10

Theory, Synthesis, and Application of Adiabatic and Reversible Logic Circuits For Security Applications

Morrison, Matthew Arthur 23 November 2013 (has links)
Programmable reversible logic is emerging as a prospective logic design style for implementation in modern nanotechnology and quantum computing with minimal impact on circuit heat generation. Adiabatic logic is a design methodology for reversible logic in CMOS where the current flow through the circuit is controlled such that the energy dissipation due to switching and capacitor dissipation is minimized. Recent advances in reversible logic using and quantum computer algorithms allow for improved computer architectures. Production of cost-effective Secure Integrated Chips, such as Smart Cards, requires hardware designers to consider tradeoffs in size, security, and power consumption. In order to design successful security-centric designs, the low-level hardware must contain built-in protection mechanisms to supplement cryptographic algorithms such as AES and Triple DES by preventing side channel attacks, such as Differential Power Analysis (DPA). Dynamic logic obfuscates the output waveforms and the circuit operation, reducing the effectiveness of the DPA attack. Significant research exists in the design and analysis of locally optimal adiabatic elements towards mitigation of side channel attacks. However, none of these works have addressed the use of adiabatic logic in implementation of flexible and programmable hardware security policies. Nor has adiabatic logic been employed in hardware security applications such as trustworthy voting systems and data encryption standards. In this dissertation, I address theory, synthesis, and application of adiabatic and reversible logic circuits for security applications. First, two major debates in reversible computing are addressed. These debates must be addressed in order to devise computational logic primitives in any emerging quantum computing technology. First, we address whether charged based computing is limited due to the use of charge as a state variable. We propose the use of body biasing in CMOS adiabatic systems as a design methodology for reducing the need for gradually changing the energy barriers. Simulation results in HSPICE at 22nm are presented which show behavior of a source-memory device operating at sub-Landauer operation. Second, we address whether reversible logic can be used to design sequential computing structures, such as memory devices. we present an analysis of Quantum Turing Machines with sequential reversible logic structures, to show that the entropy gain is substantially less than the Landauer Barrier of kTln(2), which is the limiting factor for irreversible computing. A mathematical proof is presented showing bit erasure does not occur in sequential reversible logic structures, and that these devices are physically reversible as long as appropriate delay elements are inserted in the feedback paths to prevent race conditions. This proof validates implementation of sequential reversible logic towards ultra-low power computing. Next, a novel algorithm for synthesis of adiabatic circuits in CMOS is proposed. This approach is unique because it correlates the offsets in the permutation matrix to the transistors required for synthesis, instead of determining an equivalent circuit and substituting a previously synthesized circuit from a library. Parallelism is used, and the bijective properties of the device to achieve synthesis of the logic structure in O(n) time. Then, using the ESPRESSO heuristic for minimization of Boolean functions method on each output node in parallel, we optimize the synthesized circuit. It is demonstrated that the algorithm produces a 32.86% improvement over previously synthesized circuit benchmarks. For stronger mitigation of DPA attacks, we propose the implementation of Adiabatic Dynamic Differential Logic for applications in secure IC design. Such an approach is effective in reducing power consumption, demonstrated using HSPICE simulations with 22nm predictive technology. The benefits of our design are demonstrated by comparing instantaneous power waveforms and observing the magnitude of differential power spikes during switching events. First, simulation results for body-biasing on sub-threshold adiabatic inverters show an improvement in differential power up to 43.28% for similar inverters without body biasing. Then, a High Performance Adiabatic Dynamic Differential Logic (PADDL) is presented for an implementation in high frequency secure ICs. This method improves the differential power over previous dynamic and differential logic methods by up to 89.65%. Finally, we propose a Body-Biased Adiabatic Dynamic Differential Logic (BADDL) for ultra-low power applications. Simulation results show that the differential power was improved upon by a factor of 199.16. Then, we present an adiabatic S-box which significantly reduces energy imbalance compared to previous benchmarks. The design is capable of forward encryption and reverse decryption with minimal overhead, allowing for efficient hardware reuse.

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