The Linux Pseudorandom Number Generator Revisited

déposé sur Cryptology ePrint Archive (http://eprint.iacr.org/)The Linux pseudorandom number generator (PRNG) is a PRNG with entropy inputs which is widely used in many security related applications and protocols. This PRNG is written as an open source code which is subject to regular changes. It was last analyzed in the work of Gutterman et al. in 2006 [GPR06] but since then no new analysis has been made available, while in the meantime several changes have been applied to the code, among others, to counter the attacks presented in [GPR06]. Our work describes the Linux PRNG of kernel versions 2.6.30.7 and upwards. We detail the PRNG architecture in the Linux system and provide its first accurate mathematical description and a precise analysis of the building blocks, including entropy estimation and extraction. Subsequently, we give a security analysis including the feasibility of cryptographic attacks and an empirical test of the entropy estimator. Finally, we underline some important changes to the previous versions and their consequences

Os 5 Desprezíveis : desenvolvimento de um jogo eletrônico utilizando os princípios de Engenharia de Software

Monografia (graduação)—Universidade de Brasília, Faculdade UnB Gama, Curso de Engenharia de Software, 2013.Aplicação de metodologia de análise de retorno sobre investimento no contexto do Centro de Qualidade e Testes de Software Esse trabalho passa por todo o ciclo de vida de um jogo, desde a pré-produção até a pós-produção, abordando características específicas, tais como o desenvolvimento de conteúdo artístico e o desenvolvimento do game design. A experiência a ser relatada leva em consideração a aplicação de Engenharia de Software nesse processo, através do levantamento de metodologias traduzidas para contexto de jogos e de ferramentas específicas. São apresentados os dois documentos de game design desenvolvidos para o jogo e o processo de escolhas que levaram a conclusão e a construção de um jogo viável. Junto com esses documentos, as ferramentas utilizadas para a codificação e prototipação também são mostradas, com as suas vantagens e desvantagens verificadas ao longo do desenvolvimento. Por fim, os principais erros do desenvolvimento e os seus resultados no jogo concluído são apresentados como uma forma de aprendizado e novas áreas de pesquisa são sugeridas para trabalhos futuros. ___________________________________________________________________________ ABSTRACTThis paper go through the entire life cycle of a game, from pre-production to post-production, addressing specific features, such as the development of artistic content and the development of game design. The experiment to be reported takes into account the application of Software Engineering in the process by surveying methodologies translated into the context of games and specific tools. Both game design documents developed for the game and the choices that led to the completion process and the construction of a viable game are presented. Along with these documents, the tools used for coding and prototyping are also shown, with their advantages and disadvantages verified throughout the development. Finally, the main errors of development and its results are presented in the game finished as a form of learning and new research areas are suggested for future work

Secure random numbers from quantum images.

: Generazione di numeri casuali sicuri tramite l’implementazione di QRNG ottico basato sul modello PBS (Polarize Beam Splitter

Side-channel attacks and countermeasures in the design of secure IC's devices for cryptographic applications

Abstract--- A lot of devices which are daily used have to guarantee the retention of sensible data. Sensible data are ciphered by a secure key by which only the key holder can get the data. For this reason, to protect the cipher key against possible attacks becomes a main issue. The research activities in hardware cryptography are involved in finding new countermeasures against various attack scenarios and, in the same time, in studying new attack methodologies. During the PhD, three different logic families to counteract Power Analysis were presented and a novel class of attacks was studied. Moreover, two different activities related to Random Numbers Generators have been addressed

Hardware design of cryptographic algorithms for low-cost RFID tags

Mención Internacional en el título de doctorRadio Frequency Identification (RFID) is a wireless technology for automatic identification that has experienced a notable growth in the last years. RFID is an important part of the new trend named Internet of Things (IoT), which describes a near future where all the objects are connected to the Internet and can interact between them. The massive deployment of RFID technology depends on device costs and dependability. In order to make these systems dependable, security needs to be added to RFID implementations, as RF communications can be accessed by an attacker who could extract or manipulate private information from the objects. On the other hand, reduced costs usually imply resource-constrained environments. Due to these resource limitations necessary to low-cost implementations, typical cryptographic primitives cannot be used to secure low-cost RFID systems. A new concept emerged due to this necessity, Lightweight Cryptography. This term was used for the first time in 2003 by Vajda et al. and research on this topic has been done widely in the last decade. Several proposals oriented to low-cost RFID systems have been reported in the literature. Many of these proposals do not tackle in a realistic way the multiple restrictions required by the technology or the specifications imposed by the different standards that have arose for these technologies. The objective of this thesis is to contribute in the field of lightweight cryptography oriented to low-cost RFID tags from the microelectronics point of view. First, a study about the implementation of lightweight cryptographic primitives is presented . Specifically, the area used in the implementation, which is one of the most important requirements of the technology as it is directly related to the cost. After this analysis, a footprint area estimator of lightweight algorithms has been developed. This estimator calculates an upper-bound of the area used in the implementation. This estimator will help in making some choices at the algorithmic level, even for designers without hardware design skills. Second, two pseudo-random number generators have been proposed. Pseudorandom number generators are essential cryptographic blocks in RFID systems. According to the most extended RFID standard, EPC Class-1 Gen-2, it is mandatory to include a generator in RFID tags. Several architectures for the two proposed generators have been presented in this thesis and they have been integrated in two authentication protocols, and the main metrics (area, throughput and power consumption) have been analysed. Finally, the topic of True Random Number Generators is studied. These generators are also very important in secure RFID, and are currently a trending research line. A novel generator, presented by Cherkaoui et al., has been evaluated under different attack scenarios. A new true random number generator based on coherent sampling and suitable for low-cost RFID systems has been proposed.La tecnología de Identificación por Radio Frecuencia, más conocida por sus siglas en inglés RFID, se ha convertido en una de las tecnologías de autoidentificación más importantes dentro de la nueva corriente de identificación conocida como Internet de las Cosas (IoT). Esta nueva tendencia describe un futuro donde todos los objetos están conectados a internet y son capaces de identificarse ante otros objetos. La implantación masiva de los sistemas RFID está hoy en día limitada por el coste de los dispositivos y la fiabilidad. Para que este tipo de sistemas sea fiable, es necesario añadir seguridad a las implementaciones RFID, ya que las comunicaciones por radio frecuencia pueden ser fácilmente atacadas y la información sobre objetos comprometida. Por otro lado, para que todos los objetos estén conectados es necesario que el coste de la tecnología de identificación sea muy reducido, lo que significa una gran limitación de recursos en diferentes ámbitos. Dada la limitación de recursos necesaria en implementaciones de bajo coste, las primitivas criptográficas típicas no pueden ser usadas para dotar de seguridad a un sistema RFID de bajo coste. El concepto de primitiva criptográfica ligera fue introducido por primera vez 2003 por Vajda et al. y ha sido desarrollado ampliamente en los últimos años, dando como resultados una serie de algoritmos criptográficos ligeros adecuados para su uso en tecnología RFID de bajo coste. El principal problema de muchos de los algoritmos presentados es que no abordan de forma realista las múltiples limitaciones de la tecnología. El objetivo de esta tesis es el de contribuir en el campo de la criptografía ligera orientada a etiquetas RFID de bajo coste desde el punto de vista de la microelectrónica. En primer lugar se presenta un estudio de la implementación de las primitivas criptográficas ligeras más utilizadas, concretamente analizando el área ocupado por dichas primitivas, ya que es uno de los parámetros críticos considerados a la hora de incluir dichas primitivas criptográficas en los dispositivos RFID de bajo coste. Tras el análisis de estas primitivas se ha desarrollado un estimador de área para algoritmos criptográficos ultraligeros que trata de dar una cota superior del área total ocupada por el algoritmo (incluyendo registros y lógica de control). Este estimador permite al diseñador, en etapas tempranas del diseño y sin tener ningún conocimiento sobre implementaciones, saber si el algoritmo está dentro de los límites de área mpuestos por la tecnología RFID. También se proponen 2 generadores de números pseudo-aleatorios. Estos generadores son uno de los bloques criptográficos más importantes en un sistema RFID. El estándar RFID más extendido entre la industria, EPC Class-1 Gen-2, establece el uso obligatorio de dicho tipo de generadores en las etiquetas RFID. Los generadores propuestos han sido implementados e integrados en 2 protocolos de comunicación orientados a RFID, obteniendo buenos resultados en las principales características del sistema. Por último, se ha estudiado el tema de los generadores de números aleatorios. Este tipo de generadores son frecuentemente usados en seguridad RFID. Actualmente esta línea de investigación es muy popular. En esta tesis, se ha evaluado la seguridad de un novedoso TRNG, presentado por Cherkaoui et al., frente ataques típicos considerados en la literatura. Además, se ha presentado un nuevo TRNG de bajo coste basado en la técnica de muestreo por pares.Programa Oficial de Doctorado en Ingeniería Eléctrica, Electrónica y AutomáticaPresidente: Teresa Riesgo Alcaide.- Secretario: Emilio Olías Ruiz.- Vocal: Giorgio di Natal