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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.
81

Forward security from bilinear pairings signcryption and threshold signature /

Chow, Sze-ming, Sherman. January 2004 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.
82

Anonymous T-out-of-N threshold signature schemes

Maneva-Jakimoska, Karolina. Burmester, Mike. January 2006 (has links)
Thesis (M.S.)--Florida State University, 2006. / Advisor: Mike Burmester, Florida State University,College of Arts amd Sciences, Dept. of Computer Science. Title and description from dissertation home page (viewed June 19, 2006). Document formatted into pages; contains viii, 40 pages. Includes bibliographical references.
83

Assinaturas tafonômicas de gastrópodes atuais do litoral de Rio de Janeiro e São Paulo : biodiversidade e implicações ambientais. /

Pinto, Maria Clara da Silva January 2017 (has links)
Orientador: Renato Pirani Ghilard / Resumo: Estudos actuopaleontológicos sobre os danos que o ambiente e outros organismos causam nas conchas de gastrópodes, tanto fósseis como atuais no Brasil, são incipientes e há pouca produção na área. Este trabalho estudou as frequências de cinco assinaturas tafonômicas, tais como abrasão, fragmentação, bioerosão, incrustação e dissolução observadas em 895 bioclastos coletados em três localidades da costa litorânea brasileira: Macaé-RJ, com sua linha de costa aberta, desprotegida e adjacente à área de ressurgência de Cabo Frio-RJ; Ubatuba-SP, com linha de costa recortada, caracterizada por pouca energia; e Cananéia-SP no extremo sul paulista, com sua linha de costa aberta e influência estuarina. As coletas bióticas a abióticas, realizadas em parceria com o LabCam (Unesp/Bauru), aconteceram mensalmente, de junho de 2013 a julho de 2014, com a utilização de barco camaroeiro e rede de arrasto em profundidades de 5 a 15 metros. A Olivancillaria urceus e a Buccinanops gradatus se destacaram pela quantidade entre as 16 espécies identificadas nas três localidades. Demarcaram-se padrões de assinaturas tafonômicas em dois diferentes grupos (subambientes), relacionados principalmente com a estabilidade da concha/sedimento. Esta estabilidade mostrou relação com a profundidade, recorte da costa e distância geográfica de ilhas, área de ressurgência e correntes. Esta observação permitirá estabelecer termos comparativos para o estudo de concentrações fossilíferas, melhorando o entendimento de su... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
84

Assinaturas tafonômicas de gastrópodes atuais do litoral de Rio de Janeiro e São Paulo: biodiversidade e implicações ambientais. / Taphonomic presentations of current gastropods from the coast of Rio de Janeiro and São Paulo: biodiversity and environmental implications.

Pinto, Maria Clara da Silva 31 October 2017 (has links)
Submitted by Maria Clara da Silva Pinto null (mclara_sb@hotmail.com) on 2018-03-03T14:00:12Z No. of bitstreams: 3 Assinaturas tafonômicas de gastrópodes atuais do litoral de Rio de Janeiro e São Paulo_biodiversidade e implicações ambientais..pdf: 5013362 bytes, checksum: 5d5df8e5ce5af9639d990602e43d57b4 (MD5) ficha catalográfica.pdf: 10100 bytes, checksum: 949a488d1c7e4d47fa66d9d50d74c33d (MD5) folhadeaprovação.pdf: 357664 bytes, checksum: 791242f1905789dd0f4af122ed46a4c1 (MD5) / Rejected by Disleide Silvia Valerio Gounella null (disleide@clp.unesp.br), reason: REJEITADO EM 05/03/2018 A Folha de Aprovação deverá aparecer no corpo do trabalho, ou seja, junto com o texto. Consultar a Instrução Normativa 01/2014 – CLP, artigo 50, Inciso II, que diz que a sobre a ficha catalográfica; Consultar a Instrução Normativa 01/2014 – CLP , Artigo 50, Inciso VIII, que diz sobre Referência bibliográfica; Favor fazer um arquivo só com o nome do título do trabalho. Está aparecendo desta forma para mim. Abrir arquivo Dissertação (4.781Mb) ficha catalográfica (9.863Kb) folha de aprovação (349.2Kb) Qualquer dúvida, entre em contato. abs. Disleide Silvia Valerio Gounella Bibliotecária CLP - São Vicente Fone: (13)3569-7154 Mailto: disleide@clp.unesp.br skype: disleidesilviavaleriogounella on 2018-03-05T16:29:35Z (GMT) / Submitted by Maria Clara da Silva Pinto null (mclara_sb@hotmail.com) on 2018-03-05T20:45:03Z No. of bitstreams: 1 Assinaturas tafonômicas de gastrópodes atuais do litoral de Rio de Janeiro e São Paulo_biodiversidade e implicações ambientais..pdf: 5077914 bytes, checksum: 52adaf9dd757e15edbfd5a34ed87fcb9 (MD5) / Rejected by Disleide Silvia Valerio Gounella null (disleide@clp.unesp.br), reason: Bom dia. Estão faltando as palavars chaves em inglês. abs. Disleide on 2018-03-06T14:32:16Z (GMT) / Submitted by Maria Clara da Silva Pinto null (mclara_sb@hotmail.com) on 2018-03-06T15:33:24Z No. of bitstreams: 1 Assinaturas tafonômicas de gastrópodes atuais do litoral de Rio de Janeiro e São Paulo_biodiversidade e implicações ambientais..pdf: 5077914 bytes, checksum: 52adaf9dd757e15edbfd5a34ed87fcb9 (MD5) / Rejected by Disleide Silvia Valerio Gounella null (disleide@clp.unesp.br), reason: Maria Claro, bom dia. Faltou o nome do co-orientador. abs. Disleide on 2018-03-07T13:48:35Z (GMT) / Submitted by Maria Clara da Silva Pinto null (mclara_sb@hotmail.com) on 2018-03-07T13:57:26Z No. of bitstreams: 1 Assinaturas tafonômicas de gastrópodes atuais do litoral de Rio de Janeiro e São Paulo_biodiversidade e implicações ambientais..pdf: 5077914 bytes, checksum: 52adaf9dd757e15edbfd5a34ed87fcb9 (MD5) / Approved for entry into archive by Disleide Silvia Valerio Gounella null (disleide@clp.unesp.br) on 2018-03-08T18:42:09Z (GMT) No. of bitstreams: 1 pinto_mcs_me_svci.pdf: 5077914 bytes, checksum: 52adaf9dd757e15edbfd5a34ed87fcb9 (MD5) / Made available in DSpace on 2018-03-08T18:42:09Z (GMT). No. of bitstreams: 1 pinto_mcs_me_svci.pdf: 5077914 bytes, checksum: 52adaf9dd757e15edbfd5a34ed87fcb9 (MD5) Previous issue date: 2017-10-31 / Estudos actuopaleontológicos sobre os danos que o ambiente e outros organismos causam nas conchas de gastrópodes, tanto fósseis como atuais no Brasil, são incipientes e há pouca produção na área. Este trabalho estudou as frequências de cinco assinaturas tafonômicas, tais como abrasão, fragmentação, bioerosão, incrustação e dissolução observadas em 895 bioclastos coletados em três localidades da costa litorânea brasileira: Macaé-RJ, com sua linha de costa aberta, desprotegida e adjacente à área de ressurgência de Cabo Frio-RJ; Ubatuba-SP, com linha de costa recortada, caracterizada por pouca energia; e Cananéia-SP no extremo sul paulista, com sua linha de costa aberta e influência estuarina. As coletas bióticas a abióticas, realizadas em parceria com o LabCam (Unesp/Bauru), aconteceram mensalmente, de junho de 2013 a julho de 2014, com a utilização de barco camaroeiro e rede de arrasto em profundidades de 5 a 15 metros. A Olivancillaria urceus e a Buccinanops gradatus se destacaram pela quantidade entre as 16 espécies identificadas nas três localidades. Demarcaram-se padrões de assinaturas tafonômicas em dois diferentes grupos (subambientes), relacionados principalmente com a estabilidade da concha/sedimento. Esta estabilidade mostrou relação com a profundidade, recorte da costa e distância geográfica de ilhas, área de ressurgência e correntes. Esta observação permitirá estabelecer termos comparativos para o estudo de concentrações fossilíferas, melhorando o entendimento de sua gênese e contribuindo, assim, para o aprimoramento da interpretação paleoecológica.
85

Verificação oportunista de assinaturas digitais para programas e bibliotecas em sistemas operacionais paginados

Destefani, Guilherme Herrmann 10 2010 (has links)
Este trabalho apresenta a combinação de uma série de mecanismos de segurança baseados em criptografia com conceitos de sistemas operacionais. Esta combinação cria uma arquitetura inovadora,que aproveita características do funcionamento do sistema operacional para protegê-lo de vulnerabilidades relacionadas com a adulteração de programas e bibliotecas. Esta arquitetura consiste em um mecanismo de geração de assinaturas digitais integradas a programas e bibliotecas, para garantir a autenticidade e a integridade dos mesmos e de cada parte do sistema operacional em execução. O sistema funciona de forma transparente para programadores, e possibilita que o software com assinaturas digitais seja compatível com sistemas que não tenham suporte a verificação de assinatura, simplificando o processo de distribuição. A verificação de assinaturas é integrada com o mecanismo de paginação do microprocessador, de forma a efetuar uma verificação sob demanda somente da parte dos programas e bibliotecas que é efetivamente utilizada. Esta integração diminui o impacto sobre o desempenho e proporciona transparência para os usuários finais e administradores de sistemas. A validação do modelo proposto foi realizada como uma extensão à interface binária de aplicação Unix ELF, implementada na plataforma GNU/Linux. O impacto da assinatura digital para desenvolvedores e distribuidores de sistemas operacionais sob a ótica de complexidade de uso, efeitos do sistema para usuários finais e a sobrecarga no desempenho do sistema foram verificados. / This work discusses a series of security mechanisms based in cryptography, combining them with concepts of operating systems, in order to create an innovative architecture that uses some functionalities characteristics of operating system to protect it against vulnerabilities related with the adulteration of computer programs and libraries. This architecture consists in a mechanism for generation of digital signatures integrated into the computer programs and libraries, in order to guarantee the software and operating system authenticity and integrity while in execution by the target machine. The system is transparent to programmers, and it is also possible that software with digital signatures can be executed on systems without support to verification of signature, what simplifies the software distribution process. The verification of signatures is integrated with the paging mechanism of the microprocessor, making on-demand verification only in the part of the programs and libraries that is going to be effectively used, diminishing the impact on the performance and providing transparency for final users and system administrators. The validation of the model was carried through as an extension to the application binary interface Unix ELF, implemented in the GNU/Linux platform. The impact of the digital signature for developers and distributors of operating systems under the point of view of complexity, effect for final users and overload in performance of the system was verified. xix
86

Verificação oportunista de assinaturas digitais para programas e bibliotecas em sistemas operacionais paginados

Destefani, Guilherme Herrmann 10 2010 (has links)
Este trabalho apresenta a combinação de uma série de mecanismos de segurança baseados em criptografia com conceitos de sistemas operacionais. Esta combinação cria uma arquitetura inovadora,que aproveita características do funcionamento do sistema operacional para protegê-lo de vulnerabilidades relacionadas com a adulteração de programas e bibliotecas. Esta arquitetura consiste em um mecanismo de geração de assinaturas digitais integradas a programas e bibliotecas, para garantir a autenticidade e a integridade dos mesmos e de cada parte do sistema operacional em execução. O sistema funciona de forma transparente para programadores, e possibilita que o software com assinaturas digitais seja compatível com sistemas que não tenham suporte a verificação de assinatura, simplificando o processo de distribuição. A verificação de assinaturas é integrada com o mecanismo de paginação do microprocessador, de forma a efetuar uma verificação sob demanda somente da parte dos programas e bibliotecas que é efetivamente utilizada. Esta integração diminui o impacto sobre o desempenho e proporciona transparência para os usuários finais e administradores de sistemas. A validação do modelo proposto foi realizada como uma extensão à interface binária de aplicação Unix ELF, implementada na plataforma GNU/Linux. O impacto da assinatura digital para desenvolvedores e distribuidores de sistemas operacionais sob a ótica de complexidade de uso, efeitos do sistema para usuários finais e a sobrecarga no desempenho do sistema foram verificados. / This work discusses a series of security mechanisms based in cryptography, combining them with concepts of operating systems, in order to create an innovative architecture that uses some functionalities characteristics of operating system to protect it against vulnerabilities related with the adulteration of computer programs and libraries. This architecture consists in a mechanism for generation of digital signatures integrated into the computer programs and libraries, in order to guarantee the software and operating system authenticity and integrity while in execution by the target machine. The system is transparent to programmers, and it is also possible that software with digital signatures can be executed on systems without support to verification of signature, what simplifies the software distribution process. The verification of signatures is integrated with the paging mechanism of the microprocessor, making on-demand verification only in the part of the programs and libraries that is going to be effectively used, diminishing the impact on the performance and providing transparency for final users and system administrators. The validation of the model was carried through as an extension to the application binary interface Unix ELF, implemented in the GNU/Linux platform. The impact of the digital signature for developers and distributors of operating systems under the point of view of complexity, effect for final users and overload in performance of the system was verified. xix
87

Quantum correlations in continuous variable mixed states : from discord to signatures

Croal, Callum January 2016 (has links)
This thesis studies continuous variable mixed states with the aim of better understanding the fundamental behaviour of quantum correlations in such states, as well as searching for applications of these correlations. I first investigate the interesting phenomenon of discord increase under local loss and explain the behaviour by considering the non-orthogonality of quantum states. I then explore the counter-intuitive result where entanglement can be created by a passive optical beamsplitter, even if the input states are classical, as long as the input states are part of a larger globally nonclassical system. This result emphasises the importance of global correlations in a quantum state, and I propose an application of this protocol in the form of quantum dense coding. Finally, I develop a quantum digital signature protocol that can be described entirely using the continuous variable formalism. Quantum digital signatures provide a method to ensure the integrity and provenance of a message using quantum states. They follow a similar method to quantum key distribution (QKD), but require less post-processing, which means they can sometimes be implemented over channels that are inappropriate for QKD. The method I propose uses homodyne measurement to verify the signature, unlike previous protocols that use single photon detection. The single photon detection of previous methods is designed to give unambiguous results about the signature, but this comes at the cost of getting no information much of the time. Using homodyne detection has the advantage of giving results all the time, but this means that measurement results always have some ambiguity. I show that, even with this ambiguity, the signature protocol based on homodyne measurement outperforms previous protocols, with the advantage enhanced when technical considerations are included. Therefore this represents an interesting new direction in the search for a practical quantum digital signature scheme.
88

Thermal Imaging As A Biometrics Approach To Facial Signature Authentication

Guzman Tamayo, Ana M 07 November 2011 (has links)
This dissertation develops an image processing framework with unique feature extraction and similarity measurements for human face recognition in the mid-wave infrared portion of the electromagnetic spectrum. The goal is to design specialized algorithms that would extract vasculature information, create a thermal facial signature and identify the individual. The objective is to use such findings in support of a biometrics system for human identification with a high degree of accuracy and a high degree of reliability. This last assertion is due to the minimal to no risk for potential alteration of the intrinsic physiological characteristics seen through thermal imaging. Thermal facial signature authentication is fully integrated and consolidates the main and critical steps of feature extraction, registration, matching through similarity measures, and validation through the principal component analysis. Feature extraction was accomplished by first registering the images to a reference image using the functional MRI of the Brain’s (FMRIB’s) Linear Image Registration Tool (FLIRT) modified to suit thermal images. This was followed by segmentation of the facial region using an advanced localized contouring algorithm applied on anisotropically diffused thermal images. Thermal feature extraction from facial images was attained by performing morphological operations such as opening and top-hat segmentation to yield thermal signatures for each subject. Four thermal images taken over a period of six months were used to generate a thermal signature template for each subject to contain only the most prevalent and consistent features. Finally a similarity measure technique was used to match images to the signature templates and the Principal Component Analysis (PCA) was used to validating the results of the matching process. Thirteen subjects were used for testing the developed technique on an in-house thermal imaging system. The matching using the similarity measures showed 88% accuracy in case of skeletonized feature signatures and 90% accuracy for anisotropically diffused feature signatures. The highly accurate results obtained in the matching process along with the generalized design process clearly demonstrate the ability of the developed thermal infrared system to be used on other thermal imaging based systems and related databases.
89

Analysis of the Use of OpenID Connect for Electronic Signatures

Sjöholm, Markus January 2021 (has links)
The use of digital services has never been as important as it is today.It is possible to do everything from researching family history to banktransactions on the Internet. This creates a demand for secure servicesto ensure secure authentication of users. Electronic signatures havebecome an important part of e-identification over the last year due tothe the COVID-19 pandemic forcing many people to work remotely.OpenID Connect, or OIDC, is a framework that supports secureauthentication and authorization. But, it does not support electronicsignatures. The work done in this project has shown that an extensionof the OIDC framework is feasible for electronic signatures.A proof of concept has been built to analyse if an extension tothe OIDC framework was possible. The signature flow implementedis structured according to a proposal developed by an experiencedgroup of people working with e-identification. It extends the OIDCauthentication request with additional information to enable supportfor electronic signatures. The signature is done using BankID as an IDP.This work shows that it is possible to perform an electronic sig-nature, with an OpenID Connect authentication flow with signatureextension. The work has focuses on one model using an IDP thatperforms signing. An approach with a stand-alone signature service ispossible, but would be more complex for a limited proof of concept.
90

Kan man lita på en elektronisk underskrift? : En studie av tillförlitligheten hos de olika kategorierna av elektroniska underskrifter / Can you trust an electronic signature?

Alhanko, Gustaf January 2022 (has links)
Everything regarding signatures, both physical and electronic, is based upon trust between the contracting parties. A signature must therefore be both reliable and secure to be used by the parties. In the recent years the use of electronic signatures has increased, and a legal framework has been established by the European union (EU) with the EU-regulation on electronic identification and trust services for electronic transactions in the internal market (eIDAS).  In the regulation three different categories of electronic signatures occur: the (simple) electronic signature, the advanced electronic signature and the qualified electronic signature. What mainly distinguishes the categories are the level of safety devices connected to the signature. The qualified electronic signature has the highest level of safety devices, followed by the advanced electronic signature, which is followed by the simple electronic signature that has either few or no safety devices. Swedish law differs from the eIDAS since there is no division into different categories. In this essay I examine and evaluate the safety, and thus the reliability of, the different categories of electronic signatures are. This is done through methods established in precedents from Swedish Courts.  The conclusion of the essay is that the reliability and safety of the electronic signature correlates with the level of safety devices connected to the signature. If an electronic signature has a higher level of safety devices, it should be regarded as more reliable and secure. I therefore advice contracting parties to use the simple electronic signatures with caution, especially if the contract is of high value, and instead use an electronic signature with more robust safety devices.

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