Plaintext awareness in identity-based key encapsulation

The notion of plaintext awareness ( PA ) has many applications in public key cryptography: it offers unique, stand-alone security guarantees for public key encryption schemes, has been used as a sufficient condition for proving indistinguishability against adaptive chosen-ciphertext attacks ( IND-CCA ), and can be used to construct privacy-preserving protocols such as deniable authentication. Unlike many other security notions, plaintext awareness is very fragile when it comes to differences between the random oracle and standard models; for example, many implications involving PA in the random oracle model are not valid in the standard model and vice versa. Similarly, strategies for proving PA of schemes in one model cannot be adapted to the other model. Existing research addresses PA in detail only in the public key setting. This paper gives the first formal exploration of plaintext awareness in the identity-based setting and, as initial work, proceeds in the random oracle model. The focus is laid mainly on identity-based key encapsulation mechanisms (IB-KEMs), for which the paper presents the first definitions of plaintext awareness, highlights the role of PA in proof strategies of IND-CCA security, and explores relationships between PA and other security properties. On the practical side, our work offers the first, highly efficient, general approach for building IB-KEMs that are simultaneously plaintext-aware and IND-CCA -secure. Our construction is inspired by the Fujisaki-Okamoto (FO) transform, but demands weaker and more natural properties of its building blocks. This result comes from a new look at the notion of γ -uniformity that was inherent in the original FO transform. We show that for IB-KEMs (and PK-KEMs), this assumption can be replaced with a weaker computational notion, which is in fact implied by one-wayness. Finally, we give the first concrete IB-KEM scheme that is PA and IND-CCA -secure by applying our construction to a popular IB-KEM and optimizing it for better performance.

Lattice-based certificateless public-key encryption in the standard model

The notion of certificateless public-key encryption (CL-PKE) was introduced by Al-Riyami and Paterson in 2003 that avoids the drawbacks of both traditional PKI-based public-key encryption (i.e., establishing public-key infrastructure) and identity-based encryption (i.e., key escrow). So CL-PKE like identity-based encryption is certificate-free, and unlike identity-based encryption is key escrow-free. In this paper, we introduce simple and efficient CCA-secure CL-PKE based on (hierarchical) identity-based encryption. Our construction has both theoretical and practical interests. First, our generic transformation gives a new way of constructing CCA-secure CL-PKE. Second, instantiating our transformation using lattice-based primitives results in a more efficient CCA-secure CL-PKE than its counterpart introduced by Dent in 2008.

Non-Abelian monopoles break color. I. Classical mechanics

Monopoles which are sources of non-Abelian magnetic flux are predicted by many models of grand unification. It has been argued elsewhere that a generic transformation of the "unbroken" symmetry group H cannot be globally implemented on such monopoles for reasons of topology. In this paper, we show that similar topological obstructions are encountered in the mechanics of a test particle in the field of these monopoles and that the transformations of H cannot all be globally implemented as canonical transformations. For the SU(5) model, if H is SU(3)C×U(1)em, a consequence is that color multiplets are not globally defined, while if H is SU(3)C×SU(2)WS×U(1)Y, the same is the case for both color and electroweak multiplets. There are, however, several subgroups KT, KT′,… of H which can be globally implemented, with the transformation laws of the observables differing from group to group in a novel way. For H=SU(3)C×U(1)em, a choice for KT is SU(2)C×U(1)em, while for H=SU(3)C×SU(2)WS×U(1)Y, a choice is SU(2)C×U(1)×U(1)×U(1). The paper also develops the differential geometry of monopoles in a form convenient for computations.

En los albores de la celestinesca : Sobre el "Romance nuevamente hecho de Calisto y Melibea" en el pliego suelto de 1513

El Romance nueuamente hecho de Calisto y Melibea, pliego suelto impreso en 1513 (Jacobo Cromberger, Sevilla), un "romance-cuento" (según Menéndez Pidal) de 680 versos octosilábicos, atestigua una pronta transformación genérica: de la prosa dramática de Celestina a un poema narrativo con narrador extradiegético. La trama concisa incluye los típicos motivos narrativos del romancero hispánico (por ejemplo, el protagonista como un cazador) y acentúa el tema del pecado y el castigo (tomado de los paratextos de Celestina), también presente en los primeros pliegos sueltos cantados por ciegos. Existen evidencias de que el texto base ha sido la Comedia, no la Tragicomedia. Este texto temprano debería ser considerado un hito en la historia de la celestinesca

En los albores de la celestinesca : Sobre el "Romance nuevamente hecho de Calisto y Melibea" en el pliego suelto de 1513

El Romance nueuamente hecho de Calisto y Melibea, pliego suelto impreso en 1513 (Jacobo Cromberger, Sevilla), un "romance-cuento" (según Menéndez Pidal) de 680 versos octosilábicos, atestigua una pronta transformación genérica: de la prosa dramática de Celestina a un poema narrativo con narrador extradiegético. La trama concisa incluye los típicos motivos narrativos del romancero hispánico (por ejemplo, el protagonista como un cazador) y acentúa el tema del pecado y el castigo (tomado de los paratextos de Celestina), también presente en los primeros pliegos sueltos cantados por ciegos. Existen evidencias de que el texto base ha sido la Comedia, no la Tragicomedia. Este texto temprano debería ser considerado un hito en la historia de la celestinesca

En los albores de la celestinesca : Sobre el "Romance nuevamente hecho de Calisto y Melibea" en el pliego suelto de 1513

El Romance nueuamente hecho de Calisto y Melibea, pliego suelto impreso en 1513 (Jacobo Cromberger, Sevilla), un "romance-cuento" (según Menéndez Pidal) de 680 versos octosilábicos, atestigua una pronta transformación genérica: de la prosa dramática de Celestina a un poema narrativo con narrador extradiegético. La trama concisa incluye los típicos motivos narrativos del romancero hispánico (por ejemplo, el protagonista como un cazador) y acentúa el tema del pecado y el castigo (tomado de los paratextos de Celestina), también presente en los primeros pliegos sueltos cantados por ciegos. Existen evidencias de que el texto base ha sido la Comedia, no la Tragicomedia. Este texto temprano debería ser considerado un hito en la historia de la celestinesca

Firm transformation: Advancing a Darwinian perspective

Purpose of the paper: The paper advocates a Darwinian explanation of the process of firm transformation. Existing, but generally opposing views related to the selection-adaptation debates are united to consider the dialogic nature of both approaches. It is argued that a Darwinian approach, as opposed to a neo-Darwinian or Lamarckian approach provides the means to scale the sides of a debate that has for too long divided scholars interested in firm and industry transformation. Approach: The paper addresses three specific issues to develop its Darwinian argument. Firstly, the various work of Geoff Hodgson that have for many years advanced Darwin's evolutionary ideas are used to argue the nature and application of Darwinism in the socio-economic domain. Secondly, the nature of what constitutes the elements of firm-environment interaction is considered to establish basic areas of focus through which the process of firm transformation is more understandable. Lastly, the construct absorptive capacity is likened to a mechanism of transmission through which the learning processes associated with the acquisition of favoured variations can be reconciled with the generic evolutionary processes of variation, selection, and retention. Findings: To understand the process of firm learning, the role of habits and routines must be outlined in specific detail. They cannot be assumed to perform interacting and replicating roles simultaneously. To do so, undermines the fundamental qualities of an evolutionary theory. What is the original/value of paper: The preliminary framework advanced takes us beyond the Darwinian - Lamarckian debate and provides elements of focus from which a greater understanding of the process of firm/industry transformation is possible.

Narratives of Travel and the Travelling Concept of Narrative: Genre Blending and the Art of Transformation

In this article I shall argue that understandings of what constitutes narrative, how it functions, and the contexts in which it applies have broadened in line with cultural, social and intellectual trends which have seen a blurring, if not the dissolution, of boundaries between ‘fact’ and ‘fiction’; ‘literary’ and ‘non-literary’ narrative spaces; history and story; concepts of time and space, text and image, teller and tale, representation and reality.To illustrate some of the ways in which the concept of narrative has travelled across disciplinary and generic boundaries, I shall look at The Art of Travel (de Botton 2003), with a view to demonstrating how the blending of genres works to produce a narrative that is at once personal and philosophical; visual and verbal; didactic and poetic. I shall show that such a text constitutes a site of interrogation of concepts of narrative, even as it depends on the reader’s ability to narrativize experience.

Geometrical-transformation approach to optical two-dimensional beam shaping: comment

I show that the research reported by Arieli et al. [Appl. Opt. 86, 9129 (1997)] has two serious mistakes: One is that an important factor is lost in the formula used in that study to determine the x-direction coordinate transformation; the other is the conclusion that the geometrical-transformation approach given by Arieli et al. can provide a smooth phase distribution. A potential research direction for obtaining a smooth phase distribution for a generic two-dimensional beam-shaping problem is stated. (C) 1998 Optical Society of America.

Mixed source model and its adapted vocal tract filter estimate for voice transformation and synthesis

In current methods for voice transformation and speech synthesis, the vocal tract filter is usually assumed to be excited by a flat amplitude spectrum. In this article, we present a method using a mixed source model defined as a mixture of the Liljencrants-Fant (LF) model and Gaussian noise. Using the LF model, the base approach used in this presented work is therefore close to a vocoder using exogenous input like ARX-based methods or the Glottal Spectral Separation (GSS) method. Such approaches are therefore dedicated to voice processing promising an improved naturalness compared to generic signal models. To estimate the Vocal Tract Filter (VTF), using spectral division like in GSS, we show that a glottal source model can be used with any envelope estimation method conversely to ARX approach where a least square AR solution is used. We therefore derive a VTF estimate which takes into account the amplitude spectra of both deterministic and random components of the glottal source. The proposed mixed source model is controlled by a small set of intuitive and independent parameters. The relevance of this voice production model is evaluated, through listening tests, in the context of resynthesis, HMM-based speech synthesis, breathiness modification and pitch transposition. © 2012 Elsevier B.V. All rights reserved.

No Laughing Matter: Shakespearean Melancholy and the Transformation of Comedy

Mon projet de thèse démontre le rôle essentiel que tient la mélancolie dans les comédies de Shakespeare. J’analyse sa présence au travers de multiples pièces, des farces initiales, en passant par les comédies romantiques, jusqu’aux tragicomédies qui ponctuent les dernières années de sa carrière. Je dénote ainsi sa métamorphose au sein du genre comique, passant d’une représentation individuelle se rapportant à la théorie des humeurs, à un spectre émotionnel se greffant aux structures théâtrales dans lesquelles il évolue. Je suggère que cette progression s’apparent au cycle de joie et de tristesse qui forme la façon par laquelle Shakespeare dépeint l’émotion sur scène. Ma thèse délaisse donc les théories sur la mélancolie se rapportant aux humeurs et à la psychanalyse, afin de repositionner celle-ci dans un créneau shakespearien, comique, et historique, où le mot « mélancolie » évoque maintes définitions sur un plan social, scientifique, et surtout théâtrale. Suite à un bref aperçu de sa prévalence en Angleterre durant la Renaissance lors de mon introduction, les chapitres suivants démontrent la surabondance de mélancolie dans les comédies de Shakespeare. A priori, j’explore les façons par lesquelles elle est développée au travers de La Comedie des Erreurs et Peines d’Amour Perdues. Les efforts infructueux des deux pièces à se débarrasser de leur mélancolie par l’entremise de couplage hétérosexuels indique le malaise que celle-ci transmet au style comique de Shakespere et ce, dès ces premiers efforts de la sorte. Le troisième chapitre soutient que Beaucoup de Bruit pour Rien et Le Marchand de Venise offrent des exemples parangons du phénomène par lequel des personnages mélancoliques refusent de tempérer leurs comportements afin de se joindre aux célébrations qui clouent chaque pièce. La mélancolie que l’on retrouve ici génère une ambiguïté émotionnelle qui complique sa présence au sein du genre comique. Le chapitre suivant identifie Comme il vous plaira et La Nuit des Rois comme l’apogée du traitement comique de la mélancolie entrepris par Shakespeare. Je suggère que ces pièces démontrent l’instant où les caractérisations corporelles de la mélancolie ne sont plus de mise pour le style dramatique vers lequel Shakespeare se tourne progressivement. Le dernier chapitre analyse donc Périclès, prince de Tyr et Le Conte d’Hiver afin de démontrer que, dans la dernière phase de sa carrière théâtrale, Shakespeare a recours aux taxonomies comiques élucidées ultérieurement afin de créer une mélancolie spectrale qui s’attardent au-delà des pièces qu’elle hante. Cette caractérisation se rapporte aux principes de l’art impressionniste, puisqu’elle promeut l’abandon de la précision au niveau du texte pour favoriser les réponses émotionnelles que les pièces véhiculent. Finalement, ma conclusion démontre que Les Deux Nobles Cousins représente la culmination du développement de la mélancolie dans les comédies de Shakespeare, où l’incarnation spectrale du chapitre précèdent atteint son paroxysme. La nature collaborative de la pièce suggère également un certain rituel transitif entre la mélancolie dite Shakespearienne et celle développée par John Fletcher à l’intérieure de la même pièce.

The ciao modular, standalone compiler and its generic program processing library

Ciao Prolog incorporates a module system which allows sepárate compilation and sensible creation of standalone executables. We describe some of the main aspects of the Ciao modular compiler, ciaoc, which takes advantage of the characteristics of the Ciao Prolog module system to automatically perform sepárate and incremental compilation and efficiently build small, standalone executables with competitive run-time performance, ciaoc can also detect statically a larger number of programming errors. We also present a generic code processing library for handling modular programs, which provides an important part of the functionality of ciaoc. This library allows the development of program analysis and transformation tools in a way that is to some extent orthogonal to the details of module system design, and has been used in the implementation of ciaoc and other Ciao system tools. We also describe the different types of executables which can be generated by the Ciao compiler, which offer different tradeoffs between executable size, startup time, and portability, depending, among other factors, on the linking regime used (static, dynamic, lazy, etc.). Finally, we provide experimental data which illustrate these tradeoffs.

A near real-time water surface detection method based on HSV transformation of MODIS multi-Spectral time series data

In the face of global population growth and the uneven distribution of water supply, a better knowledge of the spatial and temporal distribution of surface water resources is critical. Remote sensing provides a synoptic view of ongoing processes, which addresses the intricate nature of water surfaces and allows an assessment of the pressures placed on aquatic ecosystems. However, the main challenge in identifying water surfaces from remotely sensed data is the high variability of spectral signatures, both in space and time. In the last 10 years only a few operational methods have been proposed to map or monitor surface water at continental or global scale, and each of them show limitations. The objective of this study is to develop and demonstrate the adequacy of a generic multi-temporal and multi-spectral image analysis method to detect water surfaces automatically, and to monitor them in near-real-time. The proposed approach, based on a transformation of the RGB color space into HSV, provides dynamic information at the continental scale. The validation of the algorithm showed very few omission errors and no commission errors. It demonstrates the ability of the proposed algorithm to perform as effectively as human interpretation of the images. The validation of the permanent water surface product with an independent dataset derived from high resolution imagery, showed an accuracy of 91.5% and few commission errors. Potential applications of the proposed method have been identified and discussed. The methodology that has been developed 27 is generic: it can be applied to sensors with similar bands with good reliability, and minimal effort. Moreover, this experiment at continental scale showed that the methodology is efficient for a large range of environmental conditions. Additional preliminary tests over other continents indicate that the proposed methodology could also be applied at the global scale without too many difficulties

Bosonisation as The Hubbard-Stratonovich transformation

The problem of strongly correlated electrons in one dimension attracted attention of condensed matter physicists since early 50’s. After the seminal paper of Tomonaga [1] who suggested the first soluble model in 1950, there were essential achievements reflected in papers by Luttinger [2] (1963) and Mattis and Lieb [3] (1963). A considerable contribution to the understanding of generic properties of the 1D electron liquid has been made by Dzyaloshinskii and Larkin [4] (1973) and Efetov and Larkin [5] (1976). Despite the fact that the main features of the 1D electron liquid were captured and described by the end of 70’s, the investigators felt dissatisfied with the rigour of the theoretical description. The most famous example is the paper by Haldane [6] (1981) where the author developed the fundamentals of a modern bosonisation technique, known as the operator approach. This paper became famous because the author has rigourously shown how to construct the Fermi creation/anihilation operators out of the Bose ones. The most recent example of such a dissatisfaction is the review by von Delft and Schoeller [7] (1998) who revised the approach to the bosonisation and came up with what they called constructive bosonisation.

The transformed-stationary approach: a generic and simplified methodology for non-stationary extreme value analysis

Statistical approaches to study extreme events require, by definition, long time series of data. In many scientific disciplines, these series are often subject to variations at different temporal scales that affect the frequency and intensity of their extremes. Therefore, the assumption of stationarity is violated and alternative methods to conventional stationary extreme value analysis (EVA) must be adopted. Using the example of environmental variables subject to climate change, in this study we introduce the transformed-stationary (TS) methodology for non-stationary EVA. This approach consists of (i) transforming a non-stationary time series into a stationary one, to which the stationary EVA theory can be applied, and (ii) reverse transforming the result into a non-stationary extreme value distribution. As a transformation, we propose and discuss a simple time-varying normalization of the signal and show that it enables a comprehensive formulation of non-stationary generalized extreme value (GEV) and generalized Pareto distribution (GPD) models with a constant shape parameter. A validation of the methodology is carried out on time series of significant wave height, residual water level, and river discharge, which show varying degrees of long-term and seasonal variability. The results from the proposed approach are comparable with the results from (a) a stationary EVA on quasi-stationary slices of non-stationary series and (b) the established method for non-stationary EVA. However, the proposed technique comes with advantages in both cases. For example, in contrast to (a), the proposed technique uses the whole time horizon of the series for the estimation of the extremes, allowing for a more accurate estimation of large return levels. Furthermore, with respect to (b), it decouples the detection of non-stationary patterns from the fitting of the extreme value distribution. As a result, the steps of the analysis are simplified and intermediate diagnostics are possible. In particular, the transformation can be carried out by means of simple statistical techniques such as low-pass filters based on the running mean and the standard deviation, and the fitting procedure is a stationary one with a few degrees of freedom and is easy to implement and control. An open-source MAT-LAB toolbox has been developed to cover this methodology, which is available at https://github.com/menta78/tsEva/(Mentaschi et al., 2016).