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Implantations cryptographiques sécurisées et outils d’aide à la validation des contremesures contre les attaques par canaux cachésThuillet, Céline 30 March 2012 (has links)
Depuis plusieurs années, les composants dédiés à la sécurité comme les cartes à puce sont soumises à des attaques dites par canaux cachés. Ces attaques permettent d'exhiber les secrets en analysant des caractéristiques physiques comme la consommation du composant ou encore son temps d'exécution. Dans le cadre de cette thèse, deux contremesures ont été réalisées et appliquées à l'AES (algorithme de chiffrement symétrique). De plus, afin d'aider les développements futurs des contremesures et la validation de celles-ci, un simulateur a été développé. Il permet de réaliser des attaques grâce à un modèle de consommation défini dans les phases amont de développement. Enfin, j'ai pu participer aux groupes de travail qui ont proposé Shabal à la compétition SHA-3, qui vise à définir un nouveau standard pour les fonctions de hachage. Des implantations matérielles ont été réalisées par la suite. / For several years, the security components such as smart cards are subject to side channel attacks. These attacks allow to exhibit secrets by analyzing the physical characteristics such as power consumption or execution time. As part of this thesis, two countermeasures were carried out and applied to the AES (symmetric cipher). In addition, to help future development of countermeasures and their validation, a simulator was developed. It realizes attacks using a power consumption model defined in the early phases of development. Finally, I participated in working groups that have proposed Shabal to SHA-3 competition, which aims to define a new standard for hash functions. Hardware implementations have been made thereafter.
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On The Avalanche Properties Of Misty1, Kasumi And Kasumi-rAkleylek, Sedat 01 February 2008 (has links) (PDF)
The Global System for Mobile (GSM) Communication is the most widely used cellular technology. The privacy has been protected using some version of stream ciphers until the 3rd Generation of GSM. KASUMI, a block cipher, has been chosen as a standard algorithm in order to be used in 3rd Generation.
In this thesis, s-boxes of KASUMI, MISTY1 (former version of KASUMI) and RIJNDAEL (the Advanced Encryption Standard) are evaluated according to their linear approximation tables, XOR table distributions and satisfaction of the strict avalanche criterion (SAC). Then, the nonlinear part, FI function, of KASUMI and MISTY1 are investigated for SAC. A new FI function is defined by replacing both s-boxes of KASUMI by RIJNDAEL&rsquo / s s-box. Calling this new version KASUMI-R, it is found to have an FI function significantly better than others.
Finally, the randomness characteristics of the overall KASUMI-R for different rounds are compared to those of MISTY1 and KASUMI, in terms of avalanche weight distribution (AWD) and some statistical tests. The overall performance of the three ciphers is found to be same, although there is a significant difference in their FI functions.
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Network Security for Embedded SystemsLessner, Dirk Unknown Date (has links)
It is widely recognised that security is a concern in the design of a wide range of embedded systems. However, security for embedded systems remains an unsolved problem, which could create greater challenges in the future than security for mainstream computers today. The promise of universal connectivity for embedded systems creates increased possibilities for malicious users to gain unauthorised access to sensitive information. All modern security protocols use private-key and public-key algorithms. This thesis investigates three important cryptography algorithms (RC4, AES, and RSA) and their relevance to networked embedded systems. Limitations in processing power, battery life, communication bandwidth, memory and costs constrain the applicability of existing cryptography standards for small embedded devices. A mismatch between wide arithmetic for security (32 bit word operations) and embedded data bus widths (often only 8 or 16 bits) combined with a lack of certain operations (e. g., multi precision arithmetic) highlight a gap in the domain of networked embedded systems security. The aim of this thesis is to find feasible security solutions for networked embedded system applications. The above mentioned cryptography algorithms have been ported to three hardware platforms (Rabbit RCM3000, Xilinx Virtex 4 FPGA with MicroBlaze softcore, and a Linux desktop machine) in order to simulate several real world scenarios. Three applications bidirectional transmission with encryption and decryption for various payload length, unidirectional transmission with very short payload, and encrypted data streaming were developed to meet the simulation requirements. Several timing results were collected and used for calculating the achieved throughput. The Rabbit hardware platform, which represents the lower end in this thesis, was able to perform the RC4 crypto algorithm with a throughput of about 155 kbit/s. Thus the RC4 crypto algorithm was proven to outperform the AES crypto algorithm by a factor of 5, with AES achieving a throughput of about 32 kbit/s with the same hardware platform. The throughput was similar with the streaming application and UDP data transport. Without performing a cryto algorithm, the streaming application was able to process up to 1.5 Mbit/s. RSA was not implemented on the Rabbit hardware platform. The MicroBlaze hardware platform outperformed the Rabbit system by a factor of 5 10. It reached a throughput up to 1.5 Mbit/s with RC4 and up to 130 kbit/s with AES. The RSA algorithm reached up to 0.8 kbit/s on this hardware platform, showing that public-key ciphers are only suitable for short payload data, such as the exchange of a session key. The Linux machine was included in this test only to provide a reference to a non embedded system. The Linux performance was better than the MicroBlaze system by a factor of between 67 770, and better than the Rabbit platform by a factor of between 645 3125. Both the RC4 and the AES crypto algorithm reached a throughput of up to 100 Mbit/s on the Linux machine, with a throughput of up to 130 kbit/s reached with RSA. Hence, the Rabbit platform combined with the RC4 algorithm is suitable, for example, for MP3 streams with up to 150 kbit/s. The Rabbit platform with the AES algorithm could be used for low quality audio streams, for example for speech announcements. If a higher throughput is required, for example for video streams, the MicroBlaze could be an appropriate platform with throughput of up to 1.5 Mbit/s. Low cost embedded systems like Atmel AVR are not suitable for processing cipher algorithms developed in C. It is widely recommended that assembly language is used to develop such platforms.
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O uso de elementos da criptografia como estímulo matemático na sala de aula / The use of elements of mathematical cryptography as stimulus in the classroomCarvalho, Leandro Rodrigues de [UNESP] 28 April 2016 (has links)
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Previous issue date: 2016-04-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O grande desafio no ensino da matemática, pelo menos no meu ponto de vista como professor nos últimos dez anos, é fazer com que os alunos percebam a importância e a praticidade da matemática em suas vidas. Isso vai além das teorias da Aritmética, Álgebra ou Geometria ensinadas na educação básica. Os alunos precisam perceber que os conceitos matemáticos são ferramentas que os ajudam a compreender o mundo a sua volta. Diante disto, esta dissertação busca apresentar conceitos matemáticos que levam à compreensão da Criptografia: conceitos da Teoria dos Números e da Álgebra. Fazemos ainda, um breve histórico sobre a Criptografia descrevendo a cifra de César e as cifras afins, o Sistema RSA e alguns métodos de troca de chaves. Relatamos alguns trabalhos desenvolvidos pelos estudantes do PROFMAT neste tema e apresentamos uma proposta de atividade para os estudantes do ensino básico. Esta atividade consiste na construção de um kit de encriptação e decriptação utilizando copos descartáveis. Com dinâmicas unindo elementos da Criptografia e o aplicativo Whatsapp, como meio de troca das mensagens criptografadas, motivamos a sala de aula para o aprendizado da Divisão Euclidiana e da Permutação. Além disso, pretendemos despertar nos alunos o interesse em aprofundar-se nos estudos da Matemática, principalmente na Teoria dos Números, já que esta é uma das ferramentas fundamentais no contexto da Criptografia, uma ciência com grande aplicabilidade na atualidade. / The great challenge in teaching mathematics, at least in my point of view as a teacher in the past ten years is to make students understand the importance and practicality of mathematics in their lives. This goes beyond the theories of arithmetic, algebra or geometry taught in basic education. Students need to realize that mathematical concepts are tools that help them understand the world around them. In view of this, this dissertation aims to present mathematical concepts that lead to understanding of cryptography: concepts of number theory and algebra. We also a brief history on the Encryption describing the Caesar cipher and related figures, the RSA system and some methods of key exchange. We report some work done by students PROFMAT this theme and present a proposal activity for students of basic education. This activity consists in building a kit of encryption and decryption using disposable cups. With dynamic linking elements Encryption and Whatsapp application as a means of exchange of encrypted messages, we motivate the classroom for learning Euclidean division and permutation. In addition, we intend to arouse students' interest in deepening the study of mathematics, especially in Number Theory, as this is one of the fundamental tools in the context of cryptography, a science with great applicability today.
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Classificação automática de emoções em músicas latinas utilizando diferentes fontes de informação / Emotions automatic classification latin songs using different sources of informationPrzybysz, André Luiz 17 March 2016 (has links)
Com a quantidade de músicas disponíveis on-line, tem ocorrido uma crescente expansão nas pesquisas de informação musical e nas investigações de recuperação para sistemas automatizados. O campo de Music Information Retrieval (MIR) olha para vários aspectos relacionados à como organizar, categorizar e acessar coleções musicais. O desenvolvimento de novos métodos e a criação de novas representações musicais podem contribuir na precisão dos classificadores para o reconhecimento das emoções, uma vez que estes estão entre os maiores desafios da área de Music Emotion Recognition (MER). Esse trabalho investiga, implementa e combina três diferentes fontes de informações (cifras, áudio e letras) para a classificação automática de emoções em músicas. A metodologia de trabalho é descrita por meio das seguintes atividades: criação da base de dados Multimodal Latin Music Mood Database (MLMMD), pré-processamento dos dados, mineração e combinação dos dados. Por meio dos procedimentos foi realizada uma análise dos diferentes resultados utilizando as diferentes fontes de informação de forma individual e combinada. Primeiramente, foi possível observar que o método combinatório multimodal early fusion foi melhor do que os demais (no fusion e late fusion). Segundo, o classificador Support Vector Machine (SVM) mostrou uma média melhor que os demais. / With the growing amount of music available online, there has been an increasing expansion in research of musical information and the recovery investigations to automated systems. The Music Information Retrieval (MIR) field looks at various aspects related to how to organize, categorize, and access music collections. The development of new methods and the creation of new musical representations can contribute to the accuracy of classifiers for recognition of emotions, since these are among the greatest challenges in the area of Music Emotion Recognition (MER). This work investigates, implements and combines three different sources of information (cifras, audio and lyrics) for automatic emotion classification in songs. The following activities have been used to develop this work: database definition Multimodal Latin Music Mood Database (MLMMD), preprocessing of the different types of data, mining and combination of the different types of data. Through the procedures applied it was possible to carry out an analysis of the different results. First, it was observed that the multimodal early fusion method was better than the others other approaches (no fusion and late fusion). Second, the Support Vector Machine (SVM) showed an overall average better than the other classifiers.
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Cipher and DividualityRaunig, Gerald 29 July 2020 (has links)
The “Postscript on Control Societies” is considered one of the most accessible texts by Gilles Deleuze, contemporary, yet untimely, ahead of its time, perhaps even ahead of our time. In just a few pages, Deleuze here touches on the specifics of discipline and control and subjects them to three perspectives: history, logic, program. On closer reading, however, one comes across some stumbling blocks, where thinking falters. The paragraph in which the word ‘dividual’ appears for the first time in the text is such an instance. Of course, the individuals of control become dividuals, and the masses become banks. But what does ‘code’ mean here, and what is the difference between the ‘precept’ of disciplinary society and the ‘password’ of control society? As is so often the case, the key lies in questions of context and translation.
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FULLY HOMOMORPHIC ENCRYPTION BASED DATA ACCESS FRAMEWORK FOR PRIVACY-PRESERVING HEALTHCARE ANALYTICSGanduri, Sri Lasya 01 December 2021 (has links)
The main aim of this thesis is to develop a library for integrating fully homomorphic encryption-based computations on a standard database. The fully homomorphic encryption is an encryption scheme that allows functions to be performed directly on encrypted data without the requirement of decrypting the data and yields the same results as if the functions were run on the plaintext. This implementation is a promising solution for preserving the privacy of the health care system, where millions of patients’ data are stored. The personal health care tools gather medical data and store it in a database. Upon importing this library into the database, the data that is being entered into the database is encrypted and the computations can be performed on the encrypted data without decrypting.
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Secure and Efficient Implementations of Cryptographic PrimitivesGuo, Xu 30 May 2012 (has links)
Nowadays pervasive computing opens up many new challenges. Personal and sensitive data and computations are distributed over a wide range of computing devices. This presents great challenges in cryptographic system designs: how to protect privacy, authentication, and integrity in this distributed and connected computing world, and how to satisfy the requirements of different platforms, ranging from resource constrained embedded devices to high-end servers. Moreover, once mathematically strong cryptographic algorithms are implemented in either software or hardware, they are known to be vulnerable to various implementation attacks. Although many countermeasures have been proposed, selecting and integrating a set of countermeasures thwarting multiple attacks into a single design is far from trivial. Security, performance and cost need to be considered together.
The research presented in this dissertation deals with the secure and efficient implementation of cryptographic primitives. We focus on how to integrate cryptographic coprocessors in an efficient and secure way. The outcome of this research leads to four contributions to hardware security research. First, we propose a programmable and parallel Elliptic Curve Cryptography (ECC) coprocessor architecture. We use a systematic way of analyzing the impact of System-on-Chip (SoC) integration to the cryptographic coprocessor performance and optimize the hardware/software codesign of cryptographic coprocessors. Second, we provide a hardware evaluation methodology to the NIST SHA-3 standardization process. Our research efforts cover both of the SHA-3 fourteen Second Round candidates and five Third Round finalists. We design the first SHA-3 benchmark chip and discuss the technology impact to the SHA-3 hardware evaluation process. Third, we discuss two technology dependent issues in the fair comparison of cryptographic hardware. We provide a systematic approach to do a cross-platform comparison between SHA-3 FPGA and ASIC benchmarking results and propose a methodology for lightweight hash designs. Finally, we provide guidelines to select implementation attack countermeasures in ECC cryptosystem designs. We discuss how to integrate a set of countermeasures to resist a collection of side-channel analysis (SCA) attacks and fault attacks.
The first part of the dissertation discusses how system integration can affect the efficiency of the cryptographic primitives. We focus on the SoC integration of cryptographic coprocessors and analyze the system profile in a co-simulation environment and then on an actual FPGA-based SoC platform. We use this system-level design flow to analyze the SoC integration issues of two block ciphers: the existing Advanced Encryption Standard (AES) and a newly proposed lightweight cipher PRESENT. Next, we use hardware/software codesign techniques to design a programmable ECC coprocessor architecture which is highly flexible and scalable for system integration into a SoC architecture.
The second part of the dissertation describes our efforts in designing a hardware evaluation methodology applied to the NIST SHA-3 standardization process. Our Application Specific Integrated Circuit (ASIC) implementation results of five SHA-3 finalists are the first ASIC real measurement results reported in the literature. As a contribution to the NIST SHA-3 competition, we provide timely ASIC implementation cost and performance results of the five SHA-3 finalists in the SHA-3 standard final round evaluation process. We define a consistent and comprehensive hardware evaluation methodology to the NIST SHA-3 standardization process from Field Programmable Gate Array (FPGA) prototyping to ASIC implementation.
The third part of the dissertation extends the discussion on hardware benchmarking of NIST SHA-3 candidates by analyzing the impact of technology to the fair comparison of cryptographic hardware. First, a cross-platform comparison between the FPGA and ASIC results of SHA-3 designs demonstrates the gap between two sets of benchmarking results. We describe a systematic approach to analyze a SHA-3 hardware benchmark process for both FPGAs and ASICs. Next, by observing the interaction of hash algorithm design, architecture design, and technology mapping, we propose a methodology for lightweight hash implementation and apply it to CubeHash optimizations. Our ultra-lightweight design of the CubeHash algorithm represents the smallest ASIC implementation of this algorithm reported in the literature. Then, we introduced a cost model for analyzing the hardware cost of lightweight hash implementations.
The fourth part of the dissertation discusses SCA attacks and fault attacks resistant cryptosystem designs. We complete a comprehensive survey of state-of-the-art of secure ECC implementations and propose a methodology on selecting countermeasures to thwart multiple side-channel attacks and fault attacks. We focus on a systematic way of organizing and understanding known attacks and countermeasures. / Ph. D.
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Contrôle, synchronisation et chiffrement / Control, synchronization and encryptionParriaux, Jérémy 03 October 2012 (has links)
Cette thèse traite de la synchronisation des systèmes dynamiques.La synchronisation est étudiée pour une configuration de type maître-esclave, c'est-à-dire pour des systèmes couplés de façon unidirectionnelle. Ce type de configuration s'avère d'un intérêt tout particulier car elle correspond à des architectures de communications chiffrées un-vers-un ou un-vers-plusieurs. Une attention spécifique est portée sur l'autosynchronisation, comportement qui caractérise la synchronisation par le simple couplage maître-esclave et donc en l'absence de tout contrôle extérieur. Elle joue un rôle majeur dans les communications impliquant des chiffreurs par flot autosynchronisants. L'étude de l'autosynchronisation dans le contexte cryptographique s'appuie sur la théorie du contrôle. Un lien original entre l'autosynchronisation et le principe de chiffrement/déchiffrement en cryptographie est mis en évidence. Il fait appel à la propriété de platitude des systèmes dynamiques, un concept emprunté à l'automatique. On montre que les systèmes dynamiques plats définissent complètement l'ensemble des systèmes autosynchronisants et permettent d'élargir les structures existantes des chiffreurs autosynchronisants. La platitude est tout d'abord étudiée pour deux types de systèmes non linéaires~: les systèmes linéaires commutés et à paramètres variants (LPV). La caractérisation des sorties plates s'appuie sur le concept de semigroupes nilpotents et un algorithme performant est proposé. Une approche constructive pour réaliser des structures maître-esclave autosynchronisantes est proposée sur la base de systèmes plats et les notions d'inversibilité à gauche et à droite empruntées à la théorie du contrôle. Par la suite, l'autosynchronisation est étudiée dans le contexte booléen, privilégié en cryptographie.Elle est caractérisée en premier lieu au travers la notion d'influence. Ensuite, différentes représentations matricielles associées aux fonctions booléennes sont proposées. Ces représentations s'avèrent particulièrement intéressantes pour l'analyse des propriétés liées à la sécurité. Un lien entre l'autosynchronisation et les structures propres des représentations matricielles est établi. Une approche orientée graphes est finalement élaborée pour la caractérisation. De nouvelles constructions de structures autosynchronisantes en sont déduites et des éléments de sécurité sont discutés. Enfin, une plateforme de test à base de FPGA qui a été réalisée est décrite / This thesis deals with the synchronization of dynamical systems. The synchronization considered is called master-slave, that is, the dynamical systems are connected in a unidirectional way. This configuration is of interest because it corresponds to an architecture encountered in secured communications of type one-to-one or one-to-many. A special attention is paid to self-synchronization. A behaviour that characterizes synchronization achieved with a simple master-slave coupling and so, without any external control. It is a central feature of self-synchronizing stream ciphers. The study of self-synchronization in the cryptographic context relies on control theory. An original connection between self-synchronization and encryption/decryption is provided. It is based on the flatness property of dynamical systems, a property borrowed from automatic control. It is shown that flat dynamical systems completly define the set of all self-synchronizing systems and thus, enlarge the existing structures of self-synchronizing stream ciphers. Flatness is first of all studied for the case of two nonlinear systems: switched linear systems and linear parameter-varying (LPV) systems. Flatness caracterization is based on the concept of nilpotent semigroups and an efficient algorithm is provided. A constructive approach for self-synchronizing master-slave structures is proposed. It relies on the construction of flat systems as well as on left and right invertibility also borrowed from control theory. Then, self-synchronization is studied in the Boolean context which is preferred in cryptography. Self-synchronization is caracterized through the notion of influence. Several matrix representations of Boolean functions are proposed. These representations are especially interesting for security analysis. A connection between self-synchronization and the eigenstructures of these matrices is established. Then, a graph oriented approach is provided. New self-synchronizing constructions are deduced and security elements are discussed. Eventually, the description of a realized FPGA based test plateform is provided
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Rijndael Circuit Level CryptanalysisPehlivanoglu, Serdar 05 May 2005 (has links)
The Rijndael cipher was chosen as the Advanced Encryption Standard (AES) in August 1999. Its internal structure exhibits unusual properties such as a clean and simple algebraic description for the S-box. In this research, we construct a scalable family of ciphers which behave very much like the original Rijndael. This approach gives us the opportunity to use computational complexity theory. In the main result, we generate a candidate one-way function family from the scalable Rijndael family. We note that, although reduction to one-way functions is a common theme in the theory of public-key cryptography, it is rare to have such a defense of security in the private-key theatre.
In this thesis a plan of attack is introduced at the circuit level whose aim is not break the cryptosystem in any practical way, but simply to break the very bold Rijndael security claim. To achieve this goal, we are led to a formal understanding of the Rijndael security claim, juxtaposing it with rigorous security treatments. Several of the questions that arise in this regard are as follows: ``Do invertible functions represented by circuits with very small numbers of gates have better than worst case implementations for their inverses?' ``How many plaintext/ciphertext pairs are needed to uniquely determine the Rijndael key?'
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