scholarly journals A Digital Cash Paradigm with Valued and No-Valued e-Coins

2021 ◽  
Vol 11 (21) ◽  
pp. 9892
Author(s):  
Ricard Borges ◽  
Francesc Sebé

Digital cash is a form of money that is stored digitally. Its main advantage when compared to traditional credit or debit cards is the possibility of carrying out anonymous transactions. Diverse digital cash paradigms have been proposed during the last decades, providing different approaches to avoid the double-spending fraud, or features like divisibility or transferability. This paper presents a new digital cash paradigm that includes the so-called no-valued e-coins, which are e-coins that can be generated free of charge by customers. A vendor receiving a payment cannot distinguish whether the received e-coin is valued or not, but the customer will receive the requested digital item only in the former case. A straightforward application of bogus transactions involving no-valued e-coins is the masking of consumption patterns. This new paradigm has also proven its validity in the scope of privacy-preserving pay-by-phone parking systems, and we believe it can become a very versatile building block in the design of privacy-preserving protocols in other areas of research. This paper provides a formal description of the new paradigm, including the features required for each of its components together with a formal analysis of its security.

2021 ◽  
Vol 11 (3-4) ◽  
pp. 1-22
Author(s):  
Qiang Yang

With the rapid advances of Artificial Intelligence (AI) technologies and applications, an increasing concern is on the development and application of responsible AI technologies. Building AI technologies or machine-learning models often requires massive amounts of data, which may include sensitive, user private information to be collected from different sites or countries. Privacy, security, and data governance constraints rule out a brute force process in the acquisition and integration of these data. It is thus a serious challenge to protect user privacy while achieving high-performance models. This article reviews recent progress of federated learning in addressing this challenge in the context of privacy-preserving computing. Federated learning allows global AI models to be trained and used among multiple decentralized data sources with high security and privacy guarantees, as well as sound incentive mechanisms. This article presents the background, motivations, definitions, architectures, and applications of federated learning as a new paradigm for building privacy-preserving, responsible AI ecosystems.


Ars Adriatica ◽  
2011 ◽  
pp. 9
Author(s):  
Tin Turković ◽  
Maja Zeman

In the last two decades, the architecture of late antique country estates in Europe - most notably those in the northern provinces (Raetia, the two Germanias, Pannonia, Noricum, Moesia and Dacia), but also in the Iberian and Italian peninsula - has been systematically researched. Based on the typology of examined structures, numerous studies have yielded observations about evident similarities between late antique complexes from various parts of the Western Empire, which had adopted a completely new paradigm in the spatial arrangement of representative and lavish administrative buildings on the estates affected by the economic reforms of the late third century. The abundance of the variants of the universal theme of aulic architecture in country estates from the late third and during the fourth century has enabled the identification of regional varieties and patterns in the spreading of individual architectural solutions, as well as the defining and careful research of other phases of the architectural transformation of late antique estates. The question which this paper attempts to answer is where Dalmatian late antique villas belong in such an ‘international’ architecture of the late antique country estate, and whether their forms follow the trends of the neighbouring provinces. In the lack of finds, the only way towards a clarification of the outlined questions is a formal analysis which most Dalmatian late antique villas have not been subjected to, and which opens the door for the interpretation of the building considered essential from the art-historical perspective. Formal qualities of the villas suggest the provenance of their architectural elements, reveal the function of a structure and its parts and clarify the position of a villa in the developmental line of the architecture of country estates and indicate the likely time frame of its production.In this context, this paper focuses on the late antique complex discovered in the early twentieth century on the site of Prikače in the village of Strupnić (near Livno). The villa is, unfortunately, only known from the initial reports but its dimensions and layout make it stand out from other late antique complexes in Dalmatian hinterland. However, the modestly recorded ground plan and a recent reconstruction of this structure do leave considerable space for formal analysis and more precise conclusions about its date. The noted symmetrical division of the front part of the building with two apsed lateral spaces and axial arrangement of the central reception hall, which was most likely accessed from the courtyard, point to the comparisons with late third- and early fourth-century complexes in the Danube area, such as those at Kövágászölös or Keszthely-Fenékpuszta, which served as administrative centres of large estates along the Danube, and which may have drawn upon a luxurious complex near Parndorf. Symmetrically placed apses on the façade, an almost unique phenomenon in the Danube area, is doubtlessly rooted in the desire to make façades more monumental as can be seen in a number of buildings which span the end of the third and the beginning of the fourth century, when a certain revolution took place in the architecture of country estates, reflecting the socio-economic changes which transformed the European landscape through the enlargement of estates. It is a clear sign of the estate owner’s status and a clear indication of the building’s function. The villa at Strupnić, together with the examples at Ljusine and Livade, and the remains of the architectural complex at Majdan, points to a strong connection between Dalmatia and the trends which sprung up in the Danube area in the late third and during the fourth century, and clearly illustrates the direction through which late antique solutions in the architecture of country estates reached the interior of Dalmatia. Thus, we deem that it is not inopportune to place the time frame of the construction of Dalmatian late antique country estates in the same formal and chronological context of the estates in its northern neighbourhood which was, at that time, going through what Mocsy called the last age or prosperity in the Danube area. The formal connection with the mentioned estates implies that the function of Dalmatian and Danube structures complemented each other. Although the structure at Strupnić is relatively small (32,6 x 27,5 m), and is classified in the category of small country estates suchas those at Deutschkreuz, Sümeg, Csúcshegy, Majdan or Mali Mošunj, we deem that it is completely unfounded to interpret it as a journey station, i.e. an inn (mutatio), as Bojanovski suggested on a number of occasions. Considering the layout of the complex, a more luxurious nature of its form and its location, it seems more likely that it had been part of a richer estate which was administered from a central administrative-residential-economic complex, and in connection with this, it is advisable to return to Bojanovski’s earlier interpretations which identified it as one of the examples of praetorium fundi. During the third and fourth centuries, in the time of economic reforms and enlargement of estates, medium-sized estates of the social elite may have been situated in the area of Livanjsko polje, due to its good road networks and fortified transformations of architectural complexes in individual sites. The Strupnić late antique estate still represents a riddle of sorts the solving of which depends on future archaeological excavations that this structure undoubtedly deserves. In this paper, it has been an example of the amount of information that can be obtained from scarce records about a building when it is subjected to a formal and contextual analysis. The traditional definitions of the architecture of estates and the generalising approach which does not take into account individual features of a building need to be questioned, and this is confirmed by the example of Strupnić.


2021 ◽  
pp. 1-38
Author(s):  
Mina Sheikhalishahi ◽  
Ischa Stork ◽  
Nicola Zannone

Recent years have seen an increasing popularity of online collaborative systems like social networks and web-based collaboration platforms. Collaborative systems typically offer their users a digital environment in which they can work together and share resources and information. These resources and information might be sensitive and, thus, they should be protected from unauthorized accesses. Multi-party access control is emerging as a new paradigm for the protection of co-owned and co-managed resources, where the policies of all users involved in the management of a resource should be accounted for collaborative decision making. Existing approaches, however, only focus on the jointly protection of resources and do not address the protection of the individual user policies themselves, whose disclosure might leak sensitive information. In this work, we propose a privacy-preserving mechanism for the evaluation of multi-party access control policies, which preserves the confidentiality of user policies while remaining capable of making collaborative decisions. To this end, we design secure computation protocols for the evaluation of policies in protected form against an access query and realize such protocols using two privacy-preserving techniques, namely Homomorphic Encryption and Secure Functional Evaluation. We show the practical feasibility of our mechanism in terms of computation and communication costs through an experimental evaluation.


Author(s):  
Maik Stührenberg ◽  
Christian Wurm

This paper presents a refined taxonomy of XML schema languages based on the work by Murata et al., 2005. It can be seen as first building block for a more elaborate formal analysis of XML and its accompanied specifications, in this case: XML schema languages such as DTD, XSD and RELAX NG.


2014 ◽  
Vol 693 ◽  
pp. 22-29 ◽  
Author(s):  
Daynier Rolando Delgado Sobrino ◽  
Radovan Holubek ◽  
Peter Košťál ◽  
Roman Ružarovský

This paper essentially emerges from scientific and teaching needs of a university institute while trying deepen into a more formal analysis and/or design process of the material flow and associated manufacturing decisions, e.g.: the layout. Fulfilling such needs, the paper makes allusion to key manufacturing decisions associated to the material flow, while stressing the fact of their mandatory consideration when integrally addressing the primary problem. A partial application of the ideas takes place at a flexible assembly cell of the institute; some of the main results of it are: (1) a more formal description of the whole cell including alternative material flow scenarios, (2) the proposal of a new scenario implying the redesign of the cell conception, i.e.: the layout and thus material flow itself, (3) the simulation and comparison of material flow scenarios selecting the best one in terms of both the MF and layout, among others. At the end, the integration of all these previous elements clearly contributed to the solution of the research’ problem and objectives traced within the frame of the research.


2019 ◽  
Vol 9 (15) ◽  
pp. 3034
Author(s):  
Mohamed Ben Haj Frej ◽  
Julius Dichter ◽  
Navarun Gupta

Cloud computing is reserving its position in the market as the next disruptive utility paradigm. It is found on the pay-as-you-use model. Cloud computing is changing the way information technology (IT) operates for individuals as well as for companies. Cloud computing comes with different offerings to accommodate diverse applications. It comes with many successful adoption stories and a few unfortunate ones that are related to security breaches. Security concerns are what is making many companies reluctant to fully embrace the cloud realm. To enhance trust and entice adoption between cloud clients (CC) and cloud service providers (CSP), a new paradigm of depending on involving a third-party auditor (TPA) has been introduced. Hence, implementing a solution with a TPA comes with its toll in terms of trust and processing overhead. A lightweight security protocol to give the CC extra control with tools to audit the TPA and the CSP is paramount to the solution. In this paper, we are introducing a novel protocol: the lightweight accountable privacy-preserving (LAPP) protocol. Our proposed protocol is lightweight in terms of processing and communication costs. It is based on a newly introduced mathematical model along with two algorithms. We have conducted simulation experiments to measure the impact of our method. We have compared LAPP to the most eminent privacy-preserving methods in the cloud research field, using the open source cloud computing simulator GreenCloud. Our simulation results showed superiority in performance for LAPP in regard to time complexity, accuracy, and computation time on auditing. The aim of the time complexity and computation time on auditing simulations is to measure the lightweight aspect of our proposed protocol as well as to improve the quality of service.


2021 ◽  
Vol 2021 (4) ◽  
pp. 441-463
Author(s):  
Elizabeth C. Crites ◽  
Anna Lysyanskaya

Abstract Mercurial signatures are a useful building block for privacy-preserving schemes, such as anonymous credentials, delegatable anonymous credentials, and related applications. They allow a signature σ on a message m under a public key pk to be transformed into a signature σ′ on an equivalent message m′ under an equivalent public key pk′ for an appropriate notion of equivalence. For example, pk and pk′ may be unlinkable pseudonyms of the same user, and m and m′ may be unlinkable pseudonyms of a user to whom some capability is delegated. The only previously known construction of mercurial signatures suffers a severe limitation: in order to sign messages of length ℓ, the signer’s public key must also be of length ℓ. In this paper, we eliminate this restriction and provide an interactive signing protocol that admits messages of any length. We prove our scheme existentially unforgeable under chosen open message attacks (EUF-CoMA) under a variant of the asymmetric bilinear decisional Diffie-Hellman assumption (ABDDH).


2021 ◽  
Vol 13 (23) ◽  
pp. 4853
Author(s):  
Dawei Wei ◽  
Ning Xi ◽  
Jianfeng Ma ◽  
Lei He

Unmanned aerial vehicle (UAV) plays a more and more important role in Internet of Things (IoT) for remote sensing and device interconnecting. Due to the limitation of computing capacity and energy, the UAV cannot handle complex tasks. Recently, computation offloading provides a promising way for the UAV to handle complex tasks by deep reinforcement learning (DRL)-based methods. However, existing DRL-based computation offloading methods merely protect usage pattern privacy and location privacy. In this paper, we consider a new privacy issue in UAV-assisted IoT, namely computation offloading preference leakage, which lacks through study. To cope with this issue, we propose a novel privacy-preserving online computation offloading method for UAV-assisted IoT. Our method integrates the differential privacy mechanism into deep reinforcement learning (DRL), which can protect UAV’s offloading preference. We provide the formal analysis on security and utility loss of our method. Extensive real-world experiments are conducted. Results demonstrate that, compared with baseline methods, our method can learn cost-efficient computation offloading policy without preference leakage and a priori knowledge of the wireless channel model.


1999 ◽  
Vol 26 (1) ◽  
pp. 31-51
Author(s):  
Samantha L. Wells ◽  
Scott A. MacDonald ◽  
Norman Giesbrecht

Sign in / Sign up

Export Citation Format

Share Document