A shared cryptographic key enables strong authentication. Candidate sources for creating such a shared key include biometrics and physically unclonable functions. However, these sources come with a substantial problem: noise in repeated readings. A fuzzy extractor produces a stable key from a noisy source. It consists of two stages. At enrollment time, the generate algorithm produces a key from an initial reading of the source. At authentication time, the reproduce algorithm takes a repeated but noisy reading of the source, yielding the same key when the two readings are close. For many sources of practical importance, traditional fuzzy extractors provide no meaningful security guarantee. This dissertation improves key derivation from noisy sources. These improvements stem from three observations about traditional fuzzy extractors. First, the only property of a source that standard fuzzy extractors use is the entropy in the original reading. We observe that additional structural information about the source can facilitate key derivation. Second, most fuzzy extractors work by first recovering the initial reading from the noisy reading (known as a secure sketch). This approach imposes harsh limitations on the length of the derived key. We observe that it is possible to produce a consistent key without recovering the original reading of the source. Third, traditional fuzzy extractors provide information-theoretic security. However, security against computationally bounded adversaries is sufficient. We observe fuzzy extractors providing computational security can overcome limitations of traditional approaches. The above observations are supported by negative results and constructions. As an example, we combine all three observations to construct a fuzzy extractor achieving properties that have eluded prior approaches. The construction remains secure even when the initial enrollment phase is repeated multiple times with noisy readings. Furthermore, for many practical sources, reliability demands that the tolerated noise is larger than the entropy of the original reading. The construction provides security for sources of this type by utilizing additional source structure, producing a consistent key without recovering the original reading, and providing computational security.

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We first introduce the octonions as an eight dimensional vector space over a field of characteristic zero with a multiplication defined using a table. We also show that the multiplication rules for octonions can be derived from a special graph with seven vertices call the Fano Plane. Next we explain the Cayley-Dickson construction, which exhibits the octonions as the set of ordered pairs of quaternions. This approach parallels the realization of the complex numbers as ordered pairs of real numbers. The rest of the thesis is devoted to following a paper by N. Jacobson written in 1939 entitled "Cayley Numbers and Normal Simple Lie Algebras of Type G". We prove that the algebra of derivations on the octonions is a Lie algebra of type G_2. The proof proceeds by showing the set of derivations on the octonions is a Lie algebra, has dimension fourteen, and is semisimple. Next, we complexify the algebra of derivations on the octonions and show the complexification is simple. This suffices to show the complexification of the algebra of derivations is isomorphic to g_2 since g_2 is the only semisimple complex Lie algebra of dimension fourteen. Finally, we conclude the algebra of derivations on the octonions is a simple Lie algebra of type G_2. / Master of Science

The graduate's thesis deals with analysis of anglicisms as neologisms on the border of 20th - 21st century in Czech and Russian. In this thesis, the explanation of the causes of the intensive adoption of loanwords from English has been presented. The analysis of anglicisms from the viewpoint of stucture, morphological adaptation and word-forming has been carried out. The secondary aim of this analysis is to trace the manners of integration of anglicims into the Czech language system in comparison with the Russian language.

This thesis investigates a subset of the lexical items which appear to be involved in the phenomenon of conversion in English. In its most canonical form, conversion involves pairs or sets of word forms which share both their phonological (and orthographic) form as well as some element of meaning, but which seem to belong to di↵erent word classes. In this study, the focus is on the relationships (or lack thereof) between monosyllabic verbal and nominal forms in conversion pairs. The investigation takes as a starting point the patterns of linguistic behaviour within and across these pairs. The situation which is revealed is complex, but not unsystematic. Instead, it is shown that in many cases, the relationship between the nominal and verbal forms is clearly asymmetrical. In contrast to these clearer patterns, however, there are also a number of cases wherein the relationship appears to be more symmetrical in nature. In view of the complexity of the situation, the question of how to best model the linguistic behaviour of such forms has been a subject of some debate in the literature. A variety of theoretical explanations for these relationships have been proposed, though none has managed to account for the wide range of data. This study therefore suggests a mixed model, in which asymmetrically-related forms are involved in a derivational morphological process, while symmetrical forms represent inflected forms of a single lexeme which lacks a specification of word class. However, given the fertile – and in no way settled – research background, the primary contribution of this study is an experimental exploration of how these forms and the relationships between them might be synchronically represented in the mental grammar of current speakers. To that end, three behavioural experiments are conducted with a view to uncovering how di↵erent types of conversion items are processed, and how information about their processing might inform our theoretical understanding. The results of these experiments suggest that the processing of these forms is indeed in line with the patterns of symmetry and asymmetry found in their linguistic behaviour, and suggests that some conversion pairs may be involved in a derivational process, while others may not be pairs at all but rather a single, underspecified lexical entry. However, in addition to the results concerning the forms which display clearer patterns of behaviour, it is suggested that the patterns across the phenomenon of conversion as a whole may best be understood as a continuum, rather than all suggesting a single underlying pattern of mental representation.

Aim of this MA thesis is to describe Spanish diminutives from different points of view. After defining basic concepts from morphology and lingu- istics the study focuses on traditional and pragmatic semantics of Spanish diminutives. The pragmatic point of view is the basis for analysis of particu- lar diminutives. In the conclusion, the traditional and pragmatic approaches to Spanish diminutives are compared.

Review

Esta pesquisa tem o objetivo de entender os valores semânticos dos sufixos -sc- e -iz- nos verbos encontrados na Vulgata, num estudo sincrônico e diacrônico, considerando as informações etimológicas e avaliando a formação desses verbos nas diversas categorias. Para uma melhor compreensão dos sufixos -sc- e -iz-, observou-se sua utilização na língua grega e, a partir desta, a sua transição para o latim, o que resultou no processo de formação de palavras nesse idioma. Consideram-se os verbos, com ambos os sufixos na língua grega, e o uso deles na língua latina, ora formando novos verbos no latim, ora sendo transliterados, do grego para o latim. Além da Vulgata, o Dictionnaire Illustre Latin Français de Félix Gaffiot também é corpus para esta pesquisa a fim de perceber se os sufixos pesquisados formaram novos verbos no latim pós-clássico. Nesta comparação de corpora, pode-se notar a ausência da Vulgata nas referências dos verbos, com sufixo -sc- e -iz-, mencionado por Gaffiot. Propõe-se também nesta pesquisa, observar as assertivas dos gramáticos e linguistas quanto aos verbos produzidos com esses sufixos. Tais afirmações estão relacionadas com a semanticidade e características dos verbos, observando-se os seus aspectos, além de informar em qual período eles foram produtivos. Em suma, este estudo destina-se a considerar a Vulgata, visto que a maioria dos pesquisadores a desconsidera, produzindo conclusões divergentes quanto ao uso dos sufixos estudados nesta pesquisa. A prefixação dos verbos que utilizam o sufixo -sc- é fato que se avalia, porque as sugestões dos estudiosos dessa área propõem datas a aspecto da produção verbal. Finalmente, observou-se que os verbos com os sufixos -sc- e -iz- estão presentes nas construções de perífrases na Vulgata, divergindo em suas construções em relação à conjugação dos verbos utilizados. / The purpose of this research is to understand by means of a synchronic and diachronic study the semantic values of the suffixes -sc- and -iz- in the verbs found in the Vulgate, considering etymological information and evaluating the formation of these verbs in their diverse categories. In order to comprehend better the -sc- and -iz- suffixes, their use in the Greek language it will be observed, and from this, their transition into Latin which resulted in the process of the formation of words in that language. Verbs with both suffixes in Greek and their use in Latin will be considered, at times forming new verbs in Latin, at times being transliterated from Greek into Latin. Beside the Vulgate, the Dictionnaire Illustre Latin Français by Felix Gaffiot serves as material for research in order to see if the suffixes studied formed new verbs in post-classic Latin. In the comparison of the material, the absence of references to the Vulgate of the verbs with the -sc- and -iz- suffixes mentioned by Gaffiot can be noted. The research also proposes to investigate assertions of grammarians and linguists about verbs formed with these suffixes. Those affirmations are related to the semanticity and the grammaticality of the verbs, noting its aspects, in addition to indicating in which period they were productive. As such, this study has the goal of considering the Vulgate in the production of divergent conclusions about the use of the suffixes studied in this research, since the majority of researchers do not consider it. The prefixion of the verbs that use the suffix -sc- is evaluated because suggestions from scholars in this area propose dates with respect to verbal production. Finally, it was seen that verbs with the suffixes -sc- and -iz- are present in the construction of periphrases in the Vulgate, differing in their constructions with respect to the conjugation of the verbs used.

Este documento apresenta o Lyra, um novo esquema de derivação de chaves, baseado em esponjas criptográficas. O Lyra foi projetado para ser estritamente sequencial, fornecendo um nível elevado de segurança mesmo contra atacantes que utilizem múltiplos núcleos de processamento, como uma GPU ou FPGA. Ao mesmo tempo possui uma implementação simples em software e permite ao usuário legítimo ajustar o uso de memória e tempo de processamento de acordo com o nível de segurança desejado. O Lyra é, então, comparado ao scrypt, mostrando que esta proposta fornece um nível se segurança mais alto, além de superar suas deficiências. Caso o atacante deseje realizar um ataque utilizando pouca memória, o tempo de processamento do Lyra cresce exponencialmente, enquanto no scrypt este crescimento é apenas quadrático. Além disto, para o mesmo tempo de processamento, o Lyra permite uma utilização maior de memória, quando comparado ao scrypt, aumentando o custo de ataques de força bruta. / This document presents Lyra, a password-based key derivation scheme based on cryptographic sponges. Lyra was designed to be strictly sequential, providing strong security even against attackers that use multiple processing cores, such as FPGAs or GPUs. At the same time, it is very simple to implement in software and allows legitimate users to tune its memory and processing costs according to the desired level of security. We compare Lyra with scrypt, showing how this proposal provides a higher security level and overcomes limitations of scrypt. If the attacker wishes to perform a low-memory attack against the algorithm, the processing cost grwos expontetialy, while in scrypt, this growth is only quadratic. In addition, for an identical processing time, Lyra allows for a higher memory usage than its counterparts, further increasing the cost of brute force attacks.