Linear solutions for cryptographic nonlinear sequence generators

This letter shows that linear Cellular Automata based on rules 90/150 generate all the solutions of linear difference equations with binary constant coefficients. Some of these solutions are pseudo-random noise sequences with application in cryptography: the sequences generated by the class of shrinking generators. Consequently, this contribution show that shrinking generators do not provide enough guarantees to be used for encryption purposes. Furthermore, the linearization is achieved through a simple algorithm about which a full description is provided

Analysis of the generalized self-shrinking generator

AbstractThis work shows that the output sequences of a well-known cryptographic generator, the so-called generalized self-shrinking generator, are particular solutions of homogeneous linear difference equations with binary coefficients. In particular, all those generated sequences are just linear combinations of primary sequences weighted by binary values. Furthermore, the complete class of solutions of these difference equations includes other balanced sequences with the same period and even greater linear complexity than that of the generalized self-shrinking sequences. Cryptographic parameters of all above mentioned sequences are here analyzed in terms of linear equation solutions. In addition, this work describes an efficient algorithm to synthesize the component primary sequences as well as to compute the linear complexity and period of any generalized self-shrinking sequence

Estudio de algunas Secuencias pseudoaleatorias de aplicación criptográfica

Sin resume

A Simple Attack on Some Clock-Controlled Generators

We present a new approach to edit distance attacks on certain clock-controlled generators, which applies basic concepts of Graph Theory to simplify the search trees of the original attacks in such a way that only the most promising branches are analyzed. In particular, the proposed improvement is based on cut sets defined on some graphs so that certain shortest paths provide the edit distances. The strongest aspects of the proposal are that the obtained results from the attack are absolutely deterministic, and that many inconsistent initial states of the target registers are recognized beforehand and avoided during search

Industrialización en la vivienda social de Madrid

The use of industrialized systems often clashes with the inertia of traditional construction methods, the lack of technical knowledge and fear of a budget increase of all those agents involved in the process of design, construction and dwelling. This article stresses the relevance of systematize and rationalize the entire process. The promotion of industrial systems requires a wide understanding of the industrial context and the need of changing construction habits. It is an strategic and conscious effort to boost the construction industry, as well as a means to achieve higher quality in the product, and safer construction sites. To support the implementation of industrialized construction systems, is important to stress the environmental benefits of their use, such as recyclability, energetic efficiency of their production and the smaller amount of waste material. At last, never forget the satisfaction and participation in the whole process of the final user.El empleo de sistemas industrializados a menudo se enfrenta a las inercias de formas de construir tradicionales, al desconocimiento técnico y a la desconfianza sobre los costes de todos los implicados en el proceso de promoción, construcción y habitación. Este artículo insiste en la necesidad de sistematizar y racionalizar todo el proceso. La promoción de sistemas industriales requiere una comprensión amplia del tejido industrial y de la necesidad de modificar hábitos constructivos. Se debe entender como una apuesta estratégica consciente para impulsar la industria de la construcción, así como un medio para conseguir un producto de más calidad y mayor seguridad en obra. Para reforzar la implantación de sistemas industrializados, es importante incidir en los beneficios medioambientales de su utilización, tales como reciclaje, eficiencia energética de su producción y menor generación de residuos. También considerar como fundamental la satisfacción y participación en el proceso del que será su usuario final

Microwave-driven synthesis of bisphosphonate nanoparticles allows in vivo visualisation of atherosclerotic plaque

A fast and reproducible microwave-driven process has allowed us to synthesise neridronate-functionalised nanoparticles. Contrary to tradition, the phosphate groups decorate the outside layer of the particles providing Ca2+ binding properties in vitro and selective accumulation in vivo in the atheroma plaque. In vivo and ex vivo detection by T2-weighted MRI is demonstrated and validated by histology. The accumulation in the plaque takes place in less than one hour following the intravenous injection, which is particularly suitable for clinical applications

Cryptographic properties of Boolean functions defining elementary cellular automata

In this work, the algebraic properties of the local transition functions of elementary cellular automata (ECA) were analysed. Specifically, a classification of such cellular automata was done according to their algebraic degree, the balancedness, the resiliency, nonlinearity, the propagation criterion and the existence of non-zero linear structures. It is shown that there is not any ECA satisfying all properties at the same time

A comparison of Thellier-type and multispecimen paleointensity determinations on Pleistocene and historical lava flows from Lanzarote (Canary Islands, Spain)

Sixteen Miocene, Pleistocene, and historic lava flows have been sampled in Lanzarote (Canary Islands) for paleointensity analysis with both the Coe and multispecimen methods. Besides obtaining new data, the main goal of the study was the comparison of paleointensity results determined with two different techniques. Characteristic Remanent Magnetization (ChRM) directions were obtained in 15 flows, and 12 were chosen for paleointensity determination. In Thellier-type experiments, a selection of reliable paleointensity determinations (43 of 78 studied samples) was performed using sets of criteria of different stringency, trying to relate the quality of results to the strictness of the chosen criteria. Uncorrected and fraction and domain-state corrected multispecimen paleointensity results were obtained in all flows. Results with the Coe method on historical flows either agree with the expected values or show moderately lower ones, but multispecimen determinations display a large deviation from the expected result in one case. No relation can be detected between correct or anomalous results and paleointensity determination quality or rock-magnetic properties. However, results on historical flows suggest that agreement between both methods could be a good indicator of correct determinations. Comparison of results obtained with both methods on seven Pleistocene flows yields an excellent agreement in four and disagreements in three cases. Pleistocene determinations were only accepted if either results from both methods agreed or a result was based on a sufficiently large number (n>4) of individual Thellier-type determinations. In most Pleistocene flows, a VADM around 5 31022 Am2 was observed, although two flows displayed higher values around 931022 Am2.project CGL2012-32149 (Ministerio de Econom ıa y Competitividad, Spain), project 320/2011 (Ministerio de Medio Ambiente y Medio Rural y Marino, Spain) and the European Regional Development Fund (ERDF)