Implementação eficiente em software de criptossistemas de curvas elipticas

Orientador: Ricardo DahabTese (doutorado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: A criptografia de chave-pública é, reconhecidamente, uma ferramenta muito útil para prover requisitos de segurança tais como confidencialidade, integridade, autenticidade e não-repudio, parte integrante das comunicações. A principal vantagem dos criptossistemas de curvas elípticas (CCE) em relação a outras tecnologias de chave-pública concorrentes tais como RSA e DSA, é que parâmetros significativamente menores podem ser usados nos CCE com o mesmo nível de segurança. Essa vantagem é especialmente importante em aplicações em ambientes computacionais limitados como cartões inteligentes, telefones celulares, computadores de bolso e pagers. De um ponto de vista prático, a implementação dos CCE apresenta vários desafios. Uma aplicação baseada nos CCE precisa que várias escolhas sejam feitas tais como o nível de segurança, algoritmos para implementar a aritmética no corpo finito subjacente, algoritmos para implementar a aritmética na curva elíptica, protocolos de curvas elípticas e a plataforma computacional. Essas escolhas podem ter um grande impacto no desempenho da aplicação resultante. Esta dissertação trata do desenvolvimento de algoritmos eficientes para implementação em software de criptossistemas de curvas elípticas sobre o corpo finito F2m. Neste contexto, foram desenvolvidos métodos eficientes para implementar a aritmética no corpo finito F2m, e para calcular múltiplos de um ponto elíptico, a operação fundamental da criptografia pública baseada em curvas elípticas. Nesta dissertação também foi abordado o problema da implementação eficiente em software dos algoritmos propostos, em diferentes plataformas computacionais tais como PCs, estações de trabalho, e em dispositivos limitados como o pager da RIM.Abstract: It is widely recognized that public-key cryptography is an important tool for providing security services such as confidentiality, data integrity, authentication and non-repudiation, which are requirements present in almost all communications. The main advantage of elliptic curve cryptography (ECC) over competing public-key technologies such as RSA and DSA is that significantly smaller parameters can be used in ECC, but with equivalent levels of security. This advantage is especially important for applications on constrained environments such as smart cards, cell phones, personal device assistants, and pagers. From a practical point of view, the implementation of ECC presents various challenges. An ECC-based application requires that several choices be made including the security level, algorithms for implementing the finite field arithmetic, algorithms for implementing the elliptic group operation, elliptic curve protocols, and the computer platform. These choices may have a significant impact on the performance of the resulting application. This dissertation focuses on developing efficient algorithms for software implementation of ECC over F2m. In this framework, we study different ways of efficiently implementing arithmetic in F2¿, and computing an elliptic scalar multiplication, the central operation of public-key cryptography based on elliptic curves. We also concentrate on the software implementation of these algorithms for different platforms including PCs, workstations, and constrained devices such as the RIM interactive pager. This dissertation is a collection of five papers written in English, with an introduction and conclusions written in Portuguese.DoutoradoDoutor em Ciência da Computaçã

User-Centric Security and Privacy Mechanisms in Untrusted Networking and Computing Environments

Our modern society is increasingly relying on the collection, processing, and sharing of digital information. There are two fundamental trends: (1) Enabled by the rapid developments in sensor, wireless, and networking technologies, communication and networking are becoming more and more pervasive and ad hoc. (2) Driven by the explosive growth of hardware and software capabilities, computation power is becoming a public utility and information is often stored in centralized servers which facilitate ubiquitous access and sharing. Many emerging platforms and systems hinge on both dimensions, such as E-healthcare and Smart Grid. However, the majority information handled by these critical systems is usually sensitive and of high value, while various security breaches could compromise the social welfare of these systems. Thus there is an urgent need to develop security and privacy mechanisms to protect the authenticity, integrity and confidentiality of the collected data, and to control the disclosure of private information. In achieving that, two unique challenges arise: (1) There lacks centralized trusted parties in pervasive networking; (2) The remote data servers tend not to be trusted by system users in handling their data. They make existing security solutions developed for traditional networked information systems unsuitable. To this end, in this dissertation we propose a series of user-centric security and privacy mechanisms that resolve these challenging issues in untrusted network and computing environments, spanning wireless body area networks (WBAN), mobile social networks (MSN), and cloud computing. The main contributions of this dissertation are fourfold. First, we propose a secure ad hoc trust initialization protocol for WBAN, without relying on any pre-established security context among nodes, while defending against a powerful wireless attacker that may or may not compromise sensor nodes. The protocol is highly usable for a human user. Second, we present novel schemes for sharing sensitive information among distributed mobile hosts in MSN which preserves user privacy, where the users neither need to fully trust each other nor rely on any central trusted party. Third, to realize owner-controlled sharing of sensitive data stored on untrusted servers, we put forward a data access control framework using Multi-Authority Attribute-Based Encryption (ABE), that supports scalable fine-grained access and on-demand user revocation, and is free of key-escrow. Finally, we propose mechanisms for authorized keyword search over encrypted data on untrusted servers, with efficient multi-dimensional range, subset and equality query capabilities, and with enhanced search privacy. The common characteristic of our contributions is they minimize the extent of trust that users must place in the corresponding network or computing environments, in a way that is user-centric, i.e., favoring individual owners/users

Self-Inflicted Wounds : The 2013 Government Shutdown And The Internal Divisions Of Congressional Republicans

The aim of this thesis is to look into the 2013 government shutdown in the United States of America, which lasted from October 1 to October 16, with the purpose of studying the internal divisions that were created or made visible within the Congressional manifestation of the Republican Party. The main sources for the thesis are a pair of shutdown-inducing letters from Mark Meadows and Mike Lee to Congressional leaders, the final tallies of the votes that ended the shutdown, as well as media sources. The initial shutdown-related division was made apparent in the summer of 2013 between the 14 Senators and 80 Representatives supporting through the Meadows and Lee letters a "defunding strategy", which ultimately led to the shutdown, and the 32 Senators and 152 Representatives who opposed using said strategy to combat President Obama's healthcare reform. The final division was between the 18 Senators and 144 Representatives who opposed the final compromise that ended the shutdown and the 27 Senators and 87 Representatives who voted in favor of reopening the government. Republicans who did not sign one of the letters and who voted for the final compromise were more likely to have experience of previous government shutdowns; more likely to have seniority over their colleagues; more likely to be ideologically moderate; less likely to be affiliated with the Tea Party; and more likely to hail from competitive districts or states, while the opposite is true for the Republicans who had signed one of the letters and who opposed the final compromise. While Congressional leaders like John Boehner and Mitch McConnell were largely successful in navigating the crisis, it was the leading defunder Ted Cruz in particular who benefited from the national attention that resulted from the shutdown. While the Tea Party movement was a necessary precondition for elevating politicians such as Cruz, the shutdown crisis should not be understood as an event caused by the Tea Party alone. Pro gradu -työ tutkii Yhdysvalloissa lokakuussa 2013 puhjennutta kuusitoistapäiväistä hallintosulkukriisiä ja erityisesti niitä republikaanipuolueen sisäisiä jakolinjoja, jotka syntyivät tai paljastuivat kongressissa kriisin myötä. Tutkielman päälähteinä käytetään Mark Meadowsin ja Mike Leen kongressijohtajille lähettämiä hallintosulkuun johtaneita kirjeitä, hallintosulun päättäneiden kongressiäänestysten tuloksia sekä medialähteitä. Ensimmäinen hallintosulkuun liittyvä jakolinja republikaanien joukoissa ilmeni vuoden 2013 kesällä erimielisyytenä strategiasta, jolla presidentti Barack Obaman terveydenhuoltouudistusta pitäisi vastustaa: 14 senaattoria ja 80 edustajainhuoneen jäsentä kannattivat Meadowsin ja Leen kirjeissä peräänkuulutettua ”rahoituksen leikkaus” -strategiaa, kun taas 32 senaattoria ja 152 edustajainhuoneen jäsentä vastustivat strategiaa. Hallintosulkukriisin lopettaneen kompromissiäänestyksen yhteydessä republikaanien lopulliseksi jakolinjaksi jäi 18 senaattoria ja 144 edustajainhuoneen jäsentä kompromissia vastaan ja 27 senaattoria ja 87 edustajainhuoneen jäsentä kompromissin puolesta. Meadowsin tai Leen kirjeen allekirjoittamatta jättäneet ja loppukompromissia kannattaneet republikaanit olivat kollegoitaan todennäköisemmin aikaisempien hallintosulkujen veteraaneja, muutenkin virkaiältään kollegoitaan vanhempia, ideologialtaan maltillisempia, tiukemmin kilpailtujen vaalipiirien edustajia sekä vähemmän todennäköisesti kytköksissä teekutsuliikkeeseen – päinvastaisen ollessa totta jomman kumman kirjeen allekirjoittaneista ja loppukompromissia vastustaneista republikaaneista. Vaikka republikaanijohtajat John Boehner ja Mitch McConnell onnistuivatkin melko hyvin hallintosulkukriisin polittisissa ristipaineissa navigoinnissa, kriisistä hyötyi eniten ”rahoituksen leikkaus” -strategian näkyvin äänenkannattaja Ted Cruz, joka nousi kriisin myötä korkeaprofiiliseksi poliitikoksi. Vaikka teekutsuliike olikin välttämätön edellytys Cruzin kaltaisten poliitikkojen valtaannousulle, ei vuoden 2013 hallintosulkukriisiä tule pitää pelkästään teekutsuliikkeen aikaansaannoksena

The female aesthetic subject : questions of taste, sublimity and beauty in women's prose, 1778 to 1828, with particular reference to the works of Clara Reeve, Sophia and Harriet Lee, Elizabeth Hamilton and Jane Porter.

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN042836 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

'A Manly Desire to Learn' : the Teaching of the Classics in Nineteenth Century Scotland

This thesis presents an examination of the teaching of Latin and Greek in Scotland's universities and schools, both private and public, in the nineteenth century. This was the period when the Classics occupied a central position in Scottish education and, as a result, more undergraduates studied these ancient languages than ever before, or since. The thesis also details the very different institutional traditions exemplified by the nation's ancient schools and universities which were the subject of extensive government examination by a succession of Royal Commissions. This native, largely unexplored, tradition in teaching Latin and Greek is shown to be in marked contrast, both in content and pedagogical philosophy, to the English model as exemplified by the classical curricula taught at Oxford, Cambridge and the leading English public schools. This thesis also examines the anglophile forces which attempted to dilute this Scottish tradition of the 'democratic intellect'; a process that was accelerated by the creation, in 1873, of the Scotch Education Department, based in London, which controlled all school inspection and was later responsible for the introduction and management of the national School Leaving Certificate in 1888. The final chapter provides an examination of the importance of two events: the creation of Scotland's first modem university college, Dundee College, in 1882 and the impact of the admission of women to all the nation's universities a decade later

A U.S. History Model for Enhancing Essential Academic Learning Requirements in Reading

The relationship between reading strategies that enhance essential learning in both · reading and history was studied. A U.S. History model has been developed to make connections between the teaching of history content and reading comprehension. Research has been obtained that indicates a direct correlation between student learning in a content area classroom and the integration ofreading strategies within daily lesson plans. Secondary teachers must be taught by teacher preparation programs and coached by administrators on how to develop lesson plans based on their students\u27 need to use effective reading strategies. Secondary teachers must align their daily lessons and assessments with the state\u27s essential learnings in both their content area and in reading to ensure student success

N-variant Hardware Design

The emergence of lightweight embedded devices imposes stringent constraints on the area and power of the circuits used to construct them. Meanwhile, many of these embedded devices are used in applications that require diversity and flexibility to make them secure and adaptable to the fluctuating workload or variable fabric. While field programmable gate arrays (FPGAs) provide high flexibility, the use of application specific integrated circuits (ASICs) to implement such devices is more appealing because ASICs can currently provide an order of magnitude less area and better performance in terms of power and speed. My proposed research introduces the N-variant hardware design methodology that adds the sufficient flexibility needed by such devices while preserving the performance and area advantages of using ASICs. The N-variant hardware design embeds different variants of the design control part on the same IC to provide diversity and flexibility. Because the control circuitry usually represents a small fraction of the whole circuit, using multiple versions of the control circuitry is expected to have a low overhead. The objective of my thesis is to formulate a method that provides the following advantages: (i) ease of integration in the current ASIC design flow, (ii) minimal impact on the performance and area of the ASIC design, and (iii) providing a wide range of applications for hardware security and tuning the performance of chips either statically (e.g., post-silicon optimization) or dynamically (at runtime). This is achieved by adding diversity at two orthogonal levels: (i) state space diversity, and (ii) scheduling diversity. State space diversity expands the state space of the controller. Using state space diversity, we introduce an authentication mechanism and the first active hardware metering schemes. On the other hand, scheduling diversity is achieved by embedding different control schedules in the same design. The scheduling diversity can be spatial, temporal, or a hybrid of both methods. Spatial diversity is achieved by implementing multiple control schedules that use various parts of the chip at different rates. Temporal diversity provides variants of the controller that can operate at unequal speeds. A hybrid of both spatial and temporal diversities can also be implemented. Scheduling diversity is used to add the flexibility to tune the performance of the chip. An application of the thermal management of the chip is demonstrated using scheduling diversity. Experimental results show that the proposed method is easy to integrate in the current ASIC flow, has a wide range of applications, and incurs low overhead