Design and Analysis of Opaque Signatures

Digital signatures were introduced to guarantee the authenticity and integrity of the underlying messages. A digital signature scheme comprises the key generation, the signature, and the verification algorithms. The key generation algorithm creates the signing and the verifying keys, called also the signer’s private and public keys respectively. The signature algorithm, which is run by the signer, produces a signature on the input message. Finally, the verification algorithm, run by anyone who knows the signer’s public key, checks whether a purported signature on some message is valid or not. The last property, namely the universal verification of digital signatures is undesirable in situations where the signed data is commercially or personally sensitive. Therefore, mechanisms which share most properties with digital signatures except for the universal verification were invented to respond to the aforementioned need; we call such mechanisms “opaque signatures”. In this thesis, we study the signatures where the verification cannot be achieved without the cooperation of a specific entity, namely the signer in case of undeniable signatures, or the confirmer in case of confirmer signatures; we make three main contributions. We first study the relationship between two security properties important for public key encryption, namely data privacy and key privacy. Our study is motivated by the fact that opaque signatures involve always an encryption layer that ensures their opacity. The properties required for this encryption vary according to whether we want to protect the identity (i.e. the key) of the signer or hide the validity of the signature. Therefore, it would be convenient to use existing work about the encryption scheme in order to derive one notion from the other. Next, we delve into the generic constructions of confirmer signatures from basic cryptographic primitives, e.g. digital signatures, encryption, or commitment schemes. In fact, generic constructions give easy-to-understand and easy-to-prove schemes, however, this convenience is often achieved at the expense of efficiency. In this contribution, which constitutes the core of this thesis, we first analyze the already existing constructions; our study concludes that the popular generic constructions of confirmer signatures necessitate strong security assumptions on the building blocks, which impacts negatively the efficiency of the resulting signatures. Next, we show that a small change in these constructionsmakes these assumptions drop drastically, allowing as a result constructions with instantiations that compete with the dedicated realizations of these signatures. Finally, we revisit two early undeniable signatures which were proposed with a conjectural security. We disprove the claimed security of the first scheme, and we provide a fix to it in order to achieve strong security properties. Next, we upgrade the second scheme so that it supports a iii desirable feature, and we provide a formal security treatment of the new scheme: we prove that it is secure assuming new reasonable assumptions on the underlying constituents

Cinema at the Crossroads: Bruce Conner’s Atomic Sublime, 1958 - 2008

This dissertation examines the films of Kansas-born, San Francisco-based artist Bruce Conner (1933-2008) over a period of fifty years, and contextualizes these works against the backdrop of Cold War American culture, politics, and history.It offers close readings of Conner’s films and related activities, from his pioneering work with found footage, to the visionary works he shot with his own camera, as well as his involvement in psychedelic light shows and in the Bay Area counterculture. Throughout, I explore how Conner’s films, situated at the historical “crossroads” of the Cold War, negotiated the cultural politics of race, nation, gender, and sexuality during this fraught period, with particular attention to their complex, and often ambivalent, engagement with popular culture. The dissertation is loosely chronological, with each chapter focusing on a specific cross-section of Conner’s filmmaking practice. It begins with Conner’s first film, A MOVIE (1958), a densely packed montage of found footage fragments that is widely celebrated as an incisive critique of both Cold War ideology and the cinematic medium itself. A MOVIE is the first instance in which Conner used the iconic image that would reappear in his films over the following two decades: the atomic mushroom cloud. Footage of atomic explosions resurfaces in many later films, culminating with CROSSROADS (1976), an extended motion study comprised of archival footage of the Bikini Atoll underwater atomic tests. CROSSROADS supplies the title of this dissertation, as well as its central metaphor—“cinema at the crossroads”— and its primary hermeneutic, the “atomic sublime.” Throughout, I argue that Conner’s films visualize the tense oscillation between dystopian anxieties and utopian aspirations that epitomized the atomic age. These tensions, I propose, are encapsulated in the aesthetic category of the “atomic sublime,” which describes the paradoxical experience of “terrible beauty,” prompted by the visual spectacle of an atomic explosion. By providing an in-depth examination of Conner’s distinctive body of films, this study ultimately aims to expand the narrative of postwar American art to account for the pivotal roles played by both avant-garde cinema and West Coast artists in that history

Elsewhere: impressions of sense & nonsense

I’m not going to give it all away up front, but here are a few things you’ll find inside: a flower that tastes like peppermint, a book that smells like sunscreen, a silver orb that purrs, a woman becoming a tree, a shy rainbow, and a hat that is also a disguise. There are lists, letters, dreams, and notes. I hope there aren’t typos, but I’m only human, after all. There is sense, and there is also nonsense. If you decide to join me here, we will wander elsewhere — across different kinds of terrain, into sensory experiences, between mediums, and towards collective imagination. I will point out the ways we interact with these spaces & places: how we use our bodies to access them, our senses to interpret them, and our stories to give them meaning. I’ll talk about how much I like videogames, colors, forests, and friends. Occasionally, I’ll use big words, like “phenomenological,” to impress you. But you are smart, and I might not teach you anything new! I would like for you to think about this as the start of a journey. Did you bring everything you need? You have my permission to meander — drift in any order, direction, or logic that suits you — but I hope you won’t leave without considering the urgent work of thinking about and caring for our deep entanglement with a damaged world

Singing poets: popular music and literature in France and Greece (1945-1975).

This thesis is based on a comparative examination of popular music in Greece and France between 1945 and 1975. Its central claim is that the concept of the singing poet provided a crucial framing of the field of popular music in both countries and led to a reassessment of the links between literature and popular culture. The term singing poets is coined in order to regroup artists who used poetic texts for their songs or adopted a poetic persona themselves, but also accounts for the reception of a particular style of popular music in the period and the countries under discussion as poetic/intellectual song. Adopting a Cultural Studies approach, this thesis thus outlines the role played by the prestige of literary institutions and an idealized view of oral poetry in the conceptualization of high-popular music. It questions the presentation of certain singersongwriters as 'poets in their own right', as folk poets, auteurs, poet-composers, bards and troubadours. Books, special editions and articles published in France in the 60s are extensively examined in the first part to reveal their traditionalist consensus about the poetic value of the work of certain Auteurs-Compositeurs-Interprétes. Roland Barthes's theorization of reading (and) jouissance provides a vivid counterargument by opening up the possibility of seeing literariness and pop pleasure as symbiotic rather than mutually exclusive. The second part focuses on Greek popular music and reviews how the field of what was termed Entehno Laiko (Art-Popular) has been performatively shaped by the work of Mikis Theodorakis and Manos Hadjidakis. The significant input of literary ideals and the success of Theodorakis's Melopoiemene Poiese (Sung Poetry) project are fundamental to this process. The resulting cultural divide between 'high' and 'low' popular music spheres is reassessed by examining the 'dislocating' performance of singer-songwriter Dionysis Savvopoulos, who appeared in the mid-60s performing a hybrid mimicry of Georges Brassens and Bob Dylan. Through readings of his songs, performances and interviews, popular music emerges both as the space of a reconstructed utopia and as a subversive Other to high cultural forms

Transgression and mundanity : the global extreme metal music scene

Extreme Metal musical genres have challenged conventional notions of 'music' by developing an impenetrable sound that verges on formless noise. Extreme Metal music is produced, disseminated and consumed by musicians and fans who shun publicity within a set of obscure institutions that ensure the music's global 'underground' circulation. Within the confines of obscurity, musicians and fans explore in a highly 'transgressive' manner such themes as death, war and the occult, sometimes flirting with neo-fascist and racist discourses. This thesis develops the concept of 'scene' as a method of investigating Extreme Metal music and practice. The concept is theorised through an engagement with a wide variety of literatures, notably subcultural theory, theories of community and critical theories of space. The concept is developed so as to provide an 'holistic' method of drawing on a wide variety of incommensurate literatures and conceptual frameworks. Through the concept of scene, this thesis examines how the Extreme Metal scene is 'experienced' by its members. Detailed ethnographic, interview and other data are presented from case studies in Israel, Sweden and the United Kingdom. It is argued that scene members explore transgressive experiences that constantly threaten to exceed the confines of the scene. Yet the scene is also a 'safe' space, within which members experience the communal pleasures of 'mundanity'. Members orient their practices so as to experience the pleasures of both transgression and mundanity. They manage the resulting tensions by the practice of 'reflexive anti-reflexivity' - the wilful refusal by members to explore the contradictory consequences of their practices. Reflexive anti-reflexivity also ensures that scene members never attend to power relations within the scene, leading to the marginalisation of women and those from certain ethnic backgrounds. The thesis concludes with some reflections about the problematic role of the Extreme Metal and other music scenes in providing means of experiential 'survival' within a fraught modernity

Enchanting borders: the art & psychology of Chinese hanging scroll mounting.

Chau, Cheuk Ying.Thesis (M.Phil.)--Chinese University of Hong Kong, 2010.Includes bibliographical references (p. 265-275).Abstracts in English and Chinese; includes Chinese.List of Illustrations --- p.viAcknowledgements --- p.ixIntroduction： a Psychological Approach to the Art of Mounting --- p.1The Significance of Mounting --- p.3Classical Literature and Past Research on Chinese Mounting --- p.10a psychological approach --- p.18Dissertation Structure --- p.24Chapter Chapter One： --- Scrolling' through History --- p.33Desire to Display´ؤFrom the Warring States to the Tang Dynasty --- p.33Splendid Adornment - The Song Dynasty --- p.40Emergence of the Literati - The Ming Dynasty --- p.60Subtlest of Pastels - The Qing Dynasty --- p.74Virtual Invisibility - The Republican Period and After --- p.84A Thousand Years of Hanging Scroll Mounting --- p.92Chapter Chapter Two： --- Seeing through the Enchanting Borders --- p.97Palette and Induction --- p.99Depth and Window --- p.109Oversized Outfit and Illusionary Size --- p.120Stave Strips and Composition --- p.126psychology and chinese hanging scroll mounting --- p.133Chapter Chapter Three： --- Experiment on Aesthetic Quality of Mounting --- p.137Method --- p.141Results --- p.146Discussion --- p.149Limitations --- p.152Conclusion： Subordination of Mounting --- p.153Appendix A： Experiment Questions --- p.157Appendix b： List of Artworks Included in the Experiment --- p.159Appendix c: Artworks Presentation Sequence in Different Groups --- p.161Appendix d： Aesthetic Quality Rating Sections of Different Groups --- p.162Group k --- p.162Group L --- p.168Chapter 1.1 --- Group M --- p.174Group n --- p.180Appendix E： Means (Standard Deviations) for Aesthetic Quality Ratings --- p.186Plates --- p.187Bibliography --- p.26

Cabining Intellectual Property through a Property Paradigm

One of the most revolutionary legal changes in the past generation has been the “propertization” of intellectual property (IP). The duration and scope of rights expand without limit, and courts and companies treat IP as absolute property, bereft of any restraints. But astonishingly, scholars have not yet recognized that propertization also can lead to the narrowing of IP. In contrast to much of the literature, which criticizes the propertization of IP, this Article takes it as a given. For the transformation is irreversible, sinking its tentacles further into public and corporate consciousness (as well as the IP laws) with each passing day and precluding the likelihood that IP will return to the prepropertization era. This Article therefore ventures onto a new path, one that follows property into unexpected briar patches of limits. The secret here is that property is not as absolute as it is often claimed to be. After surveying fifty doctrines in property law, Professor Carrier synthesizes limits based on development, necessity, and equity. He then utilizes these limits to construct a new paradigm for IP. The paradigm facilitates the reorganization of defenses that courts currently recognize as well as a more robust set of defenses, which include (1) a new tripartite fair use doctrine in copyright law, (2) a new defense for public health emergencies and a recovered experimental use defense and reverse doctrine of equivalents in patent law, (3) a development-based limit to trademark dilution, and (4) a functional use defense for the right of publicity. By adopting the paradigm of property, IP has reopened the door to limits. Rediscovering these limits offers significant promise for the future of innovation and democracy