Efficient Algorithms for Elliptic Curve Cryptosystems

Elliptic curves are the basis for a relative new class of public-key schemes. It is predicted that elliptic curves will replace many existing schemes in the near future. It is thus of great interest to develop algorithms which allow efficient implementations of elliptic curve crypto systems. This thesis deals with such algorithms. Efficient algorithms for elliptic curves can be classified into low-level algorithms, which deal with arithmetic in the underlying finite field and high-level algorithms, which operate with the group operation. This thesis describes three new algorithms for efficient implementations of elliptic curve cryptosystems. The first algorithm describes the application of the Karatsuba-Ofman Algorithm to multiplication in composite fields GF((2n)m). The second algorithm deals with efficient inversion in composite Galois fields of the form GF((2n)m). The third algorithm is an entirely new approach which accelerates the multiplication of points which is the core operation in elliptic curve public-key systems. The algorithm explores computational advantages by computing repeated point doublings directly through closed formulae rather than from individual point doublings. Finally we apply all three algorithms to an implementation of an elliptic curve system over GF((216)11). We provide ablolute performance measures for the field operations and for an entire point multiplication. We also show the improvements gained by the new point multiplication algorithm in conjunction with the k-ary and improved k-ary methods for exponentiation

Labor supply response to income taxation in Mexico

Resumen: El presente artículo examina el efecto de las tasas marginales del impuesto sobre la renta en el mercado laboral en México, utilizando una versión modificada del modelo de tributación sobre la renta personal de Rosen (1976). El estudio analiza las reacciones de los trabajadores asalariados del sector formal ante los cambios en la tasa marginal del impuesto sobre la renta. Prestamos especial atención a la muestra, con el fin de controlar en nuestros cálculos el problema del alto índice de evasión fiscal en México. Comprobamos como las horas de trabajo disminuyen cuando las tasas marginales del impuesto sobre la renta aumentan. Abstract: This paper examines the effect of marginal income tax rates on labor supply in Mexico using a modified version of Rosen´s (1976) personal income taxation model. The study analyzes how salaried workers of the formal sector react to changes in the marginal income tax rate. Special attention is given to the sample, in order to control the problem of the high level of tax evasion in Mexico in our estimation. We find evidence that hours of work diminish when marginal income tax rates increase

09282 Executive Summary -- Foundations for Forgery-Resilient Cryptographic Hardware

From 05.07 to 08.07.2009, the Dagstuhl Seminar 09282 ``Foundations for Forgery-Resilient Cryptographic Hardware \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. This paper provides a summary of the motivation for the seminar and the importance of the research area, a list of the participants and the program of talks given during the seminar

Evaluacion y propuesta de mejoramiento de la distribucion espacial de una red de establecimientos educacionales utilizando Geomatica. Area de estudio: zona urbana de Parral

77 p.La geomática en conjunto con la teoría de redes y la programación lineal constituyen una poderosa herramienta para la planificación y gestión de problemas territoriales muy diversos. No obstante, las aplicaciones más habituales se han referido a temas relativos a medio ambiente, urbanismo, infraestructura, sector forestal y agrícola. En el presente proyecto de graduación se expone una aplicación de los SIG en una temática todavía poco estudiada y referida a la gestión de equipamientos sociales, particularmente a evaluar y proponer medidas de mejoramiento a la distribución espacial de los establecimientos educacionales del área urbana de la comuna de Parral. Los principales resultados demuestran que en la actualidad existe una pésima distribución espacial de los establecimientos educacionales en comparación con la situación óptima obtenida mediante la utilización de dichas técnicas y procedimientos. Al comparar ambos escenarios, de aprecia una notable mejora, pasando de 1.256 a 235 viviendas no cubiertas por el servicio, considerando un área de influencia de 700 metros. Además, la eficiencia espacial de la distribución mejora ostensiblemente, bajando de 933.752 a 827.577 unidades de recorrido para la distancia total recorrida. Por lo anteriormente expuesto, la integración de geomática, teoría de redes y programación lineal son una poderosa herramienta para la evaluación y generación de propuestas de mejoramiento para la localización – asignación de instalaciones deseables, como ocurre en este caso. Por último, es posible consignar que la metodología empleada es factible de ser replicada en otras situaciones y realidades siempre que la información necesaria se encuentre disponible para estos propósitos. Sin embargo es importante consignar que el estudio planteado, considera solamente las características espaciales de la red de establecimiento, sin considerar otros parámetros de calidad educacional./ ABSTRACT: Geomatics in conjunction with the theory of linear programming and networks are a powerful tool for the planning and management of territorial problems very diverse However, the most common applications have addressed issues relating to the environment, urban planning, infrastructure, forestry and agriculture. The present draft graduation presents an application of GIS in a thematic still little studied and referred to the management of social amenities, particularly to evaluate and propose measures to improve the spatial distribution of educational establishments in the urban area of the commune Parral. The main results show that at present there is a very bad spatial distribution of educational establishments compared with the optimal situation obtained through the use of these techniques and procedures. When comparing the two scenarios, see a marked improvement, rising from 1,256 to 235 homes not covered by the service, considering a catchment area of 700 meters. In addition, the spatial distribution efficiency improves dramatically, dropping from 933,752 to 827,577 units for the tour total distance travelled. Thus, the integration of geomatics, theory of linear programming and networks are a powerful tool for generating and evaluating proposals for improving the location - allocation of facilities desirable, as in this case. Finally, it is possible that the appropriate methodology is feasible to be replicated in other situations and realities provided that the necessary information is available for these purposes. However it is important to appropriate that the study raised, considers only the spatial characteristics of the network, without considering other parameters of educational quality

Effects of Education on the Intergenerational Transmission of Labor Income in Mexico

This paper studies the relationship between the labor market earnings of parents and their children, with a particular emphasis on education. We incorporate heterogeneity of levels of income in two ways: first, by examining the transmission mechanism of family income by grouping households according to income levels. Second, we use quantile regressions to evaluate how the earnings distribution changes over time. For this purpose, we use hourly earnings of the household head and decompose it into the estimated hourly earnings and a residual.Education, Labor Income

Physical Layer Group Key Agreement for Automotive Controller Area Networks

Distribution of cryptographic keys between devices communicating over a publicly accessible medium is an important component of secure design for networked systems. In this paper, we consider the problem of group key exchange between Electronic Control Units (ECUs) connected to the Controller Area Network (CAN) within an automobile. Typically, existing solutions map schemes defined for traditional network systems to the CAN. Our contribution is to utilize physical properties of the CAN bus to generate group keys. We demonstrate that pairwise interaction between ECUs over the CAN bus can be used to efficiently derive group keys in both authenticated and non-authenticated scenarios. We illustrate the efficiency and security properties of the proposed protocols. The scalability and security properties of our scheme are similar to multi-party extensions of Diffie-Hellman protocol, without the computational overhead of group operations

Towards Side-Channel Resistant Block Cipher Usage or Can We Encrypt Without Side-Channel Countermeasures?

Based on re-keying techniques by Abdalla, Bellare, and Borst [1,2], we consider two black-box secure block cipher based symmetric encryption schemes, which we prove secure in the physically observable cryptography model. They are proven side-channel secure against a strong type of adversary that can adaptively choose the leakage function as long as the leaked information is bounded. It turns out that our simple construction is side-channel secure against all types of attacks that satisfy some reasonable assumptions. In particular, the security turns out to be negligible in the block cipher’s block size n, for all attacks. We also show that our ideas result in an interesting alternative to the implementation of block ciphers using different logic styles or masking countermeasures

A High-Security Searchable Encryption Framework for Privacy-Critical Cloud Storage Services

Searchable encryption has received a significant attention from the research community with various constructions being proposed, each achieving asymptotically optimal complexity for specific metrics (e.g., search, update). Despite their elegancy, the recent attacks and deployment efforts have shown that the optimal asymptotic complexity might not always imply practical performance, especially if the application demands a high privacy. Hence, there is a significant need for searchable encryption frameworks that capture the recent attacks with actual deployments on cloud infrastructures to assess the practicality under realistic settings. In this article, we introduce a new Dynamic Searchable Symmetric Encryption (DSSE) framework called Incidence Matrix (IM)-DSSE, which achieves a high level of privacy, efficient search/update, and low client storage with actual deployments on real cloud settings. We harness an incidence matrix along with two hash tables to create an encrypted index, on which both search and update operations can be performed effectively with minimal information leakage. This simple set of data structures surprisingly offers a high level of DSSE security while at the same time achieving practical performance. Specifically, IM-DSSE achieves forward privacy, backward privacy and size-obliviousness properties simultaneously. We also create several DSSE variants, each offering different trade-offs (e.g., security, computation) that are suitable for different cloud applications and infrastructures. Our framework was fully-implemented and its performance was rigorously evaluated on a real cloud system (Amazon EC2). Our experimental results confirm that IM-DSSE is highly practical even when deployed on mobile phones with a large outsourced dataset. Finally, we have released our IM-DSSE framework as an open-source library for a wide development and adaptation