Techn. University, Diss., 2005--Darmstadt.

Techn. Universiẗat, Diss., 2006--Darmstadt.

Thesis (M.S.)--Rochester Institute of Technology, 2008. / Typescript. Includes bibliographical references (p. 69-72).

Thesis (M.S.)--Rochester Institute of Technology, 2008. / Typescript. Includes bibliographical references (leaves 106-107).

Thesis (M. Phil.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

Zugl.: Bochum, Univ., Diss., 2009

Thesis (M.S. in Information Technology Management)--Naval Postgraduate School, March 2010. / Thesis Advisor(s): Buddenberg, Rex. Second Reader: Housel, Thomas. "March 2010." Description based on title screen as viewed on April 27, 2010. Author(s) subject terms: Public key infrastructure, user agent, authenticity, confidentiality, integrity. Includes bibliographical references (p. 47-48). Also available in print.

Orientador: Guido Costa Souza de Araujo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-15T06:48:19Z (GMT). No. of bitstreams: 1 Amaral_LeonardoScanferla_M.pdf: 1304448 bytes, checksum: 9224f9cf24023aba78008af39e3c35bc (MD5) Previous issue date: 2009 / Resumo: A Criptografia Baseada em Identidades vem sendo cada vez mais aceita como uma alternativa à criptografia assimétrica em alguns cenários. O cálculo eficiente de emparelhamentos sobre curvas elípticas é imprescindível para o desempenho dos sistemas de Criptografia Baseada em Identidades. Nesse trabalho apresentaremos um estudo comparativo entre diferentes técnicas de implementação em hardware da aritmética em F3m para o cálculo do emparelhamento ^t, em uma plataforma de baixo custo. Nossa implementação hardware/software utiliza o processador Nios II da Altera como plataforma. Através de um mapeamento da execução do emparelhamento foram identificadas as operações aritméticas que consomem mais tempo durante o cálculo do emparelhamento; essas operações foram então implementadas como instruções/módulos especializadas em FPGA e adicionadas ao processador. Em seguida, o processador especializado foi sintetizado em FPGA e o software da aplicação de emparelhamento foi modificado para utilizar as novas instruções especializadas para o emparelhamento. Experimentos comprovam que um ganho considerável de desempenho é alcançado quando essa abordagem é comparada à abordagem de software inicial. Além disso, vamos mostrar que a abordagem Hardware/Software se mostra competitiva com relação a outras soluções / Abstract: Identity-Based Cryptography has been gradually accepted as an effective way of implementing asymmetric cryptography. The calculation of cryptographically-suitable pairings is crucial for the performance of pairing based protocols. In this work we present a comparative study of hardware implementation techniques for computing the r\T pairing over the finite field F3m using a low-cost platform based on then Altera Nios II processor. Using code profiling we identify critical field operations which concentrate most of the execution time; these operations were implemented as specialized FPGA instructions/modules and added to the processor. The specialized processor was synthesized and the application was tailored to the new hardware. Experimental results show that a considerable speedup can be achieved when compared to the baseline software-only approach. Moreover, we show that such Hardware/Software co-design approach is competitive with other solutions / Mestrado / Arquitetura e Sistemas de Computação / Mestre em Ciência da Computação

Public-key cryptography is a subject that is very important to everyone who wants confidentiality and privacy in networks. It is important to understand how public-key cryptography systems work and what flaws they have. In the first part of this report we describe some of the most common encryption schemes and key agreements. We carefully investigate their flaws, if they are broken and what threats have dire consequences. We find that the biggest issue is authentication and we present current solutions to the problem. The current solutions are flawed because they rely too much on trusting different entities. It is only required that one trusted entity becomes malicious for the entire authentication system to be compromised. Because of this we propose an alternative system in the second part, Namecoin. A risk analysis in form of an attack tree is performed on the Namecoin system, where we describe how the attacks are executed and what you can do to prevent them. We present different threats against the system and we describe how dire the consequences are and the probability of their execution. Since Namecoin is an implementation of the block chain algorithm we have also explained how the block chain works in detail. We present why we think that Namecoin is a system that should replace the currently used certificate authority system. The certificate authority system is flawed because it is centralized and dependant on that no authority makes any mistakes. The Namecoin system does not become compromised unless more than 50 % of the hashrate in the system is used with malicious intent. We have concluded that the biggest threats against Namecoin have such a low probability that they can be neglected.

NTRU is a fast public-key cryptosystem that is constructed using polynomial rings with integer coefficients. We present ETRU, an NTRU-like cryptosystem based on the Eisenstein integers. We discuss parameter selection and develop a model for the probabilty of decryption failure. We also provide an implementation of ETRU. We use theoretical and experimental data to compare the security and efficiency of ETRU to NTRU with comparable parameter sets and show that ETRU is an improvement over NTRU in terms of security.