707 research outputs found
A Trust Evaluation Method Based on Logic and Probability Theory
No full textAbstract We introduce a trust evaluation method applicable in a decentralized set-ting, in which no universally trusted authority exists. The method makes simulta-neous use of logic and probability theory. The result of the qualitative part of the method are logical arguments for and against the reliability of an entity. The quan-titative part returns the probability that the reliability of an entity can be deduced under the given assumptions and pieces of evidence, as well a corresponding prob-ability for the counter-hypothesis. Our method is a true generalization of existing methods, in particular the Credential Networks. It relies on digital signatures for authenticating messages and accounts for many-to-many relationships between en-tities and public keys. Moreover, it includes eight different types of trust relations, namely the assumption or the statement that an entity is honest, competent, reliable, or malicious, and their corresponding negations.
Towards precise semantics for authenticity and trust
No full textIn an a priori anonymous digitized world, notions such as authenticity and trust are of paramount importance. Unfortunately, the exact meaning of such key terms has never been consistently defined, and they are often used in an ambiguous way. In this paper, we introduce a new model for representing these fundamental notions in the context of rating systems in e-business applications as well as for publickey certification. When applied to existing systems, its goal is to shed light on the implicit assumptions actually made by the participants. As an example, we show that for the rating system used in eBay, there are a number of such implicit assumptions on which the drawn conclusions depend. A second example is PGP, where it turns out that the meaning of the (syntactically well-defined) certificates is not entirely clear.
Two-Layer Models for Managing Distributed Authenticity and Trust
No full textThis chapter describes the difficulty of managing authenticity and trust in large open networks. Participants of such networks are usually unknown to each other. Questioning somebody’s authenticity and trustworthiness is thus a natural reflex and an important security prerequisite. The resulting problem of properly managing authenticity and trust is an emerging research topic. The chapter proposes a common conceptual framework and compares it to several existing authenticity and trust models. The goal is to increase the awareness that authenticity and trust are not separable and to promote the corresponding two-layer requirement.</jats:p
Giedion and America: Repositioning the History of Modern Architecture
No full textSigfried Giedion (1888–1968), one of the main protagonists of the architectural avant-garde in Europe, paradoxically achieved this reputation in America, far from his homeland. Nearly all of Giedion’s books written after his initial stay at Harvard University were published in English long before they became available in his native German. Reto Geiser sheds new light on Giedion’s life and reassesses his work through the lens of cultural transformation and modernization processes. The author questions the unbroken line of developments portrayed in the historiography of modern architecture, and argues that Giedion’s position in between two cultural spheres not only caused ruptures and contradictions in his work but also productively shaped its reception on either side of the Atlantic
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