Improving chaos-based pseudo-random generators in finite-precision arithmetic

One of the widely-used ways in chaos-based cryptography to generate pseudo-random sequences is to use the least significant bits or digits of finite-precision numbers defined by the chaotic orbits. In this study, we show that the results obtained using such an approach are very prone to rounding errors and discretization effects. Thus, it appears that the generated sequences are close to random even when parameters correspond to non-chaotic oscillations. In this study, we confirm that the actual source of pseudo-random properties of bits in a binary representation of numbers can not be chaos, but computer simulation. We propose a technique for determining the maximum number of bits that can be used as the output of a pseudo-random sequence generator including chaos-based algorithms. The considered approach involves evaluating the difference of the binary representation of two points obtained by different numerical methods of the same order of accuracy. Experimental results show that such estimation can significantly increase the performance of the existing chaos-based generators. The obtained results can be used to reconsider and improve chaos-based cryptographic algorithms

A New One-Dimensional Chaotic Map and Its Use in a Novel Real-Time Image Encryption Scheme

We present a new one-dimensional chaotic map, suitable for real-time image encryption. Its theoretical analysis, performed using some specific tools from the chaos theory, shows that the proposed map has a chaotic regime and proves its ergodicity, for a large space of values of the control parameter. In addition, to argue for the good cryptographic properties of the proposed map, we have tested the randomness of the values generated by its orbit using NIST statistical suite. Moreover, we present a new image encryption scheme with a classic bimodular architecture, in which the confusion and the diffusion are assured by means of two maps of the previously proposed type. The very good cryptographic performances of the proposed scheme are proved by an extensive analysis, which was performed regarding the latest methodology in this field

Digital Image Encryption Algorithm Design Based on Genetic Hyperchaos

In view of the present chaotic image encryption algorithm based on scrambling (diffusion is vulnerable to choosing plaintext (ciphertext) attack in the process of pixel position scrambling), we put forward a image encryption algorithm based on genetic super chaotic system. The algorithm, by introducing clear feedback to the process of scrambling, makes the scrambling effect related to the initial chaos sequence and the clear text itself; it has realized the image features and the organic fusion of encryption algorithm. By introduction in the process of diffusion to encrypt plaintext feedback mechanism, it improves sensitivity of plaintext, algorithm selection plaintext, and ciphertext attack resistance. At the same time, it also makes full use of the characteristics of image information. Finally, experimental simulation and theoretical analysis show that our proposed algorithm can not only effectively resist plaintext (ciphertext) attack, statistical attack, and information entropy attack but also effectively improve the efficiency of image encryption, which is a relatively secure and effective way of image communication

Estudio de mapeos caóticos discretos y su aplicación en criptografía

"La seguridad de la información digital cada vez tiene más auge, debido al creciente uso de dispositivos móviles, además del incremento de operaciones realizadas a través de internet. Esto representa un gran reto ya que para lograr la confidencialidad, integridad y autentificación es necesario el uso de mecanismos especializados, una forma de proporcionar estos servicios es por medio de la criptografía, sin embargo, la creciente demanda requiere de nuevos algoritmos que sean más rápidos y a su vez más seguros. Una opción para lograr estos objetivos es la criptografía basada en sistemas caóticos. Este trabajo de tesis se presenta en tres partes, en la primera parte se muestran los conceptos y definiciones básicas de las ¿áreas de criptografía y sistemas dinámicos, así como las herramientas que se tienen para estudiar cada uno de estos sistemas. Además se da una visión general de estas áreas así como una clasificación, de tal forma que nos enfocaremos en cifrados en flujo y en sistemas dinámicos de tiempo discreto. Cabe señalar que los sistemas dinámicos estudiados en este trabajo a diferencia del mapeo logístico y casa de campaña son multi-modales, los cuales presentan ciertas ventajas en comparación con los mapeos uni-modales. Posteriormente se analizan las similitudes y diferencias que se encuentran en estas dos áreas, dando lugar a la criptografía caótica, la cual ha sido objeto de estudio por diversos grupos de investigación en los últimos años. En la segunda parte de este trabajo se proponen metodologías para construir dos generadores pseudo-aleatorios, los cuales son la parte fundamental en el uso de cifrados en flujo, por un lado se propone el uso de valores positivos y negativos en el parámetro de bifurcación del mapeo logístico en conjunto con retardos, de esta forma es posible construir un generador que muestra resultados satisfactorios a las pruebas estadísticas de aleatoriedad propuestas por el NIST y además no es posible reconstruir el espacio fase. Por otro lado se presenta un generador basado en mapeos multi-modales el cual obtiene una secuencia binaria por medio de la combinación de diferentes modas, la principal ventaja radica en que solo es necesario definir un mapeo para obtener diferentes comportamientos, de igual forma este generador presenta resultados satisfactorios al ser evaluado por las pruebas estadísticas propuestas por el NIST.""The security of digital information is increasingly due to increasing use of mobile devices, in addition to the increase in transactions conducted via Internet. This represents a great challenge in order to achieve confidentiality, integrity and authentication is necessary use specialized mechanisms, a way of providing these services is through cryptography, however, the growing demand requires new algorithms that are faster and safe. One option to achieve these goals is chaos based cryptography. This thesis is presented in three parts, in the first part the basic concepts and definitions of the cryptography and dynamic systems as well as the tools to study each of these systems are shown. Furthermore an overview of these areas and a classification is given, we will focus on stream ciphers and discrete time dynamical systems. Note that the dynamical systems studied in this work unlike the logistic and tent map are multimodal, which have certain advantages compared with uni-modal maps. Afterwards the similarities and differences found in these two areas are analyzed, resulting in chaotic cryptography, which has been studied by several research groups in recent years. In the second part of this work we construct two pseudo-random generators, which are an essential part in the use of stream ciphers, in one hand we propose use positive and negative values in the bifurcation parameter of the logistic map together with delays, in this way it is possible to build a generator showing satisfactory results to statistical tests of randomness proposed by the NIST and it is not possible to reconstruct the phase space. On the other hand we present a generator based on multi-modal maps which produce a binary sequence obtained by combining different modal, the main advantage is that it is only necessary to define one map for different behaviors, similarly this generator presents satisfactory results when is evaluated by statistical tests proposed by the NIST.

Recent Advances in Signal Processing

The signal processing task is a very critical issue in the majority of new technological inventions and challenges in a variety of applications in both science and engineering fields. Classical signal processing techniques have largely worked with mathematical models that are linear, local, stationary, and Gaussian. They have always favored closed-form tractability over real-world accuracy. These constraints were imposed by the lack of powerful computing tools. During the last few decades, signal processing theories, developments, and applications have matured rapidly and now include tools from many areas of mathematics, computer science, physics, and engineering. This book is targeted primarily toward both students and researchers who want to be exposed to a wide variety of signal processing techniques and algorithms. It includes 27 chapters that can be categorized into five different areas depending on the application at hand. These five categories are ordered to address image processing, speech processing, communication systems, time-series analysis, and educational packages respectively. The book has the advantage of providing a collection of applications that are completely independent and self-contained; thus, the interested reader can choose any chapter and skip to another without losing continuity

Curiosity Seekers, Time Travelers, and Avant-Garde Artists: U.S. American Literary and Artistic Responses to the Occupation of Haiti (1915-1934)

U.S. American literary and creative artists perform the work of developing a discursive response to two critical moments in Haitian history: the Revolution (1791-1804) and the U.S. Marine Occupation (1915 to 1934), inspiring imaginations and imaginary concepts. Revolutionary images of Toussaint Louverture proliferated beyond the boundaries of Haiti illuminating the complicity of colonial powers in maintaining notions of a particularized racial discourse. Frank J. Webb, a free black Philadelphian, engages a scathing critique of Thomas Carlyle’s sage prose “On the Negro Question” (1849) through the fictional depiction of a painted image of Louverture in Webb’s novel The Garies and their Friends (1857). Travel writing and ethnographies of the Occupation provide platforms for new forms of artistic production involving Vodou. Following James Weldon Johnson’s critique of U.S. policy (1920), others members of the Harlem Renaissance provide a counter narrative that reengages particular U.S. readers with Haiti’s problematic Revolution through the visual and literary lens of the Occupation experience. The pseudo journalism of William Seabrook\u27s The Magic Island (1929) serves as the poto mitan (center point) around which other creative works produced after the Occupation appear. Katherine Dunham, Zora Neale Hurston, and Maya Deren followed in Seabrook’s wake. Literature, performances, and film, as well as complementary ethnographic records for each follow from Dunham (Dances of Haiti, 1983), Hurston (Tell My Horse, 1938), and Deren (Divine Horsemen, 1953). The artistic production of these significant cultural producers may better represent their experience of fieldwork in Haiti following the Occupation. Hurston’s Their Eyes Were Watching God (1937), Dunham’s exposure of Haitian dances across the world stage, and Deren’s experimental films better capture the reciprocal effect of the ethnographic process on each in their continued presentation to contemporary audiences. Literature directly related to their production appears later in Ishmael Reed’s Mumbo Jumbo (1972), Arthur Flowers’s Another Good Loving Blues (1993), Edwidge Danticat’s Breath, Eyes, Memory (1994), and Nalo Hopkinson’s The Salt Roads (2005). These productive literatures and art forms actively engage in creating the transnational ideal of diaspora as we understand it today. All dance delicately with spirit

Tematski zbornik radova međunarodnog značaja. Tom 3 / Međunarodni naučni skup “Dani Arčibalda Rajsa”, Beograd, 3-4. mart 2015.

In front of you is the Thematic Collection of Papers presented at the International Scientific Confer-ence “Archibald Reiss Days”, which was organized by the Academy of Criminalistic and Police Studies in Belgrade, in co-operation with the Ministry of Interior and the Ministry of Education, Science and Techno-logical Development of the Republic of Serbia, National Police University of China, Lviv State University of Internal Affairs, Volgograd Academy of the Russian Internal Affairs Ministry, Faculty of Security in Skopje, Faculty of Criminal Justice and Security in Ljubljana, Police Academy “Alexandru Ioan Cuza“ in Bucharest, Academy of Police Force in Bratislava and Police College in Banjaluka, and held at the Academy of Crimi-nalistic and Police Studies, on 3 and 4 March 2015.International Scientific Conference “Archibald Reiss Days” is organized for the fifth time in a row, in memory of the founder and director of the first modern higher police school in Serbia, Rodolphe Archibald Reiss, PhD, after whom the Conference was named.The Thematic Collection of Papers contains 168 papers written by eminent scholars in the field of law, security, criminalistics, police studies, forensics, informatics, as well as members of national security system participating in education of the police, army and other security services from Spain, Russia, Ukraine, Bela-rus, China, Poland, Armenia, Portugal, Turkey, Austria, Slovakia, Hungary, Slovenia, Macedonia, Croatia, Montenegro, Bosnia and Herzegovina, Republic of Srpska and Serbia. Each paper has been reviewed by two reviewers, international experts competent for the field to which the paper is related, and the Thematic Conference Proceedings in whole has been reviewed by five competent international reviewers.The papers published in the Thematic Collection of Papers contain the overview of contemporary trends in the development of police education system, development of the police and contemporary secu-rity, criminalistic and forensic concepts. Furthermore, they provide us with the analysis of the rule of law activities in crime suppression, situation and trends in the above-mentioned fields, as well as suggestions on how to systematically deal with these issues. The Collection of Papers represents a significant contribution to the existing fund of scientific and expert knowledge in the field of criminalistic, security, penal and legal theory and practice. Publication of this Collection contributes to improving of mutual cooperation between educational, scientific and expert institutions at national, regional and international level

Study on open science: The general state of the play in Open Science principles and practices at European life sciences institutes

Nowadays, open science is a hot topic on all levels and also is one of the priorities of the European Research Area. Components that are commonly associated with open science are open access, open data, open methodology, open source, open peer review, open science policies and citizen science. Open science may a great potential to connect and influence the practices of researchers, funding institutions and the public. In this paper, we evaluate the level of openness based on public surveys at four European life sciences institute