Blockchain Papers

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Yi Qing Lu

Bitcoin is a pure electronic money based on cryptographic proof instead of trust. The principle of Bitcoin can allow any two willing parties to transact directly with each other without the need for a trusted third party. Bitcoin can represent a totally new anarchy virtual currency and an innovation of digital currency. But its development also needs to face to the security of national policy risk, technology risk and trading risks.

Rui Filipe Vieira

This work project analyses the possibility for a company to trade their goods and services for bitcoins, by joining the Bitcoin network. It analyses the technological and business requirements to join the Bitcoin Network by looking at Bitcoin’s potential to act as a mean of exchange for trade, unit of account and store of value. The analysis points to the motives, benefits and risks for investors to use the Bitcoin as a traditional currency and recommends on strategies for addressing those risks and maximizing benefits. Other than companies this report, to a lesser extent, will also analyse the Bitcoin from an investor’s point of view, this is, should an investor buy bitcoins for trade and make savings on a regular and everyday basis? A major finding in this work project is that companies could start using the Bitcoin system as a legit form of payment since the benefits of using this technology outweigh the costs and risks, given the right approach. This form of payment will contribute for the upgrade of a company’s business’ image, attract a new pool of consumers and businesses that already trade in bitcoins and pressure existing financial institutions and electronic payment vendors to upgrade their service levels.

Matthias Petutschnig

No abstract is available for this record.

Joseph A. Akinyele, Gilles Barthe, Benjamin Grégoire, Benedikt Schmidt · 5 authors

Many algorithms admit very efficient batch versions that compute simultaneously the output of the algorithms on a set of inputs. Batch algorithms are widely used in cryptography, especially in the setting of pairing-based computations, where they deliver significant speed-ups. Auto Batch is an automated tool that computes highly optimized batch verification algorithms for pairing-based signature schemes. Thanks to finely tuned heuristics, Auto Batch is able to rediscover efficient batch verifiers for several signature schemes of interest, and in some cases to output batch verifiers that outperform the best known verifiers from the literature. However, Auto Batch only provides weak guarantees (in the form of a LaTeX proof) of the correctness of the batch algorithms it outputs. In this paper, we verify the correctness and security of these algorithms using the Easy Crypt framework. To achieve this goal, we define a domain-specific language to describe verification algorithms based on pairings and provide an efficient algorithm for checking (approximate) observational equivalence between expressions of this language. By translating the output of Auto Batch to this language and applying our verification procedure, we obtain machine-checked correctness proofs of the batch verifiers. Moreover, we formalize notions of security for batch verifiers and we provide a generic proof in Easy Crypt that batch verifiers satisfy a security property called screening, provided they are correct and the original signature is unforgeable against chosen-message attacks. We apply our techniques to several well-known pairing-based signature schemes from the literature, and to Groth-Sahai zero-knowledge proofs.

Víctor Mora Afonso

No abstract is available for this record.

Nan Guo, Yuanting Jin, Kangbin Yim

During the execution of a business process users need to be authenticated by multiple component service providers, while their identities need to be shared and propagated across multi-domain in a privacy-preserving fashion. An anonymous credential-based identity verification scheme is proposed to address privacy issue. Users establish trust relationship with the federation by running the enrollment protocol, which is based on zero-knowledge proof of a set of committed attributes. The IdP cannot learn identity-related information about the user. Anonymous credentials issued by the IdP allow users to selectively disclose attributes as required and prove them in an untraceable and unlinkable way, where the IdP cannot trace the showing of credential and component service providers cannot address multiple transactions to the same user even if they collude either. With the proposed attributes proof protocols, users can prove AND and OR relation over multiple attributes, and interval and inequality relation over a single attribute as well.

James L. Greer

THE POLICIES OF THE NEW DEAL DRAMATICALLY changed political economy of nations urban areas, initiating, as one urban historian aptly characterized, the overdevelopment of suburbs and underdevelopment of cities.1 In very quick succession, federal government adopted new and sweeping policies-regulation of financial industry, extensive public works programs building all manner of infrastructure, a dramatic increase in public employment, creation of nationally funded relief for unemployed, financial assistance to states and cities, a national industrial planning effort, an emergency program to refinance homes, development of a national housing program, and many others-each responding to one or more of host of daunting problems brought on by Depression.2 Many of these new federal programs became permanent fixtures in American administrative landscape, laying foundations for new (and different) patterns of economic development in future.Housing policy was especially important in creating basis for wide scale shifts of investments and population as well as dramatic changes in demography of urban core and its suburban rings. New Deal policies, designed to re-establish investment confidence in housing sector as well as to restore employment in home construction in depths of Depression3, achieved these objectives (sometimes, much later) but in so doing brought about large scale disinvestment from housing markets across urban cores of American metropolitan areas while at same time creating a powerful set of incentives for developers to construct, financial institutions to lend, realtors to sell, and large swaths of American social strata to purchase newly developed housing that were located in increasingly decentralized areas away from America's central cities.4One particularly important outcome of these policies is home mortgage redlining-the publicly created disinvestment of a surprisingly large portion of standing housing stock across wide swaths of central city neighborhoods. Historical redlining was geographic in character and resulted from public policies formulated at national level and actions of federal agencies that implemented these policies.5 Federal agencies established empirically based risk assessments of community housing markets based on both quality, amenities, basic structural features, and upkeep of housing stock as well as social class, ethnic, and racial makeup of residents of a neighborhood.6 On basis of these assessments, a large portion of nation's neighborhood housing markets were determined to pose too high a risk for newly established long term, fully amortized mortgages that were created by New Deal legislation. These areas were denied mortgage insurance and redlined. Relatively few neighborhoods, communities where housing at that time was relatively new, had a full complement of amenities and were in good repair, were deemed an acceptable risk. In these areas, mortgage insurance was granted and conventional mortgages were available to purchasers to facilitate exchange of real estate. Additionally, almost all newly constructed housing from this time forward-in suburban locations-would be beneficiaries of this federal insurance program.The New Deal Policy Sources of Mortgage RedliningTwo pieces of New Deal legislation transformed regulation of financial institutions and revolutionized housing financing in U.S. These were Banking Act (1933) and National Housing Act (1934) that respectively created a national system of deposit guaranty and mortgage insurance, and new agencies, Federal Deposit Insurance (FDIC) and Federal Housing Administration (FHA), to implement these programs. The FDIC (and later Federal Savings and Loan Insurance Corporation [FSLIC]) and FHA were established as public corporations that were financed not from appropriations from Congress but from fees these agencies were permitted to charge to financial institutions and mortgagees. …

David Bissessar, Carlisle Adams, Dong Liu

We present a technique that uses privacy enhancing technologies and biometrics to prevent the unauthorized lending of credentials. Current credential schemes suffer the weakness that issued credentials can be transferred between users. Our technique ensures the biometric identity of the individual executing the Issue and Show protocols of an existing credential system in a manner analogous to the enrollment and verification steps in traditional biometric systems. During Issue we create Pedersen commitments on biometrically derived keys obtained from fuzzy extractors. This issue-time commitment is sealed into the issued credential. During Show a verification-time commitment is generated. Correspondence of keys is verified using a zero-knowledge proof of knowledge. The proposed approach preserves the security of the underlying credential system, protects the privacy of the biometric, and generalizes to multiple biometric modalities. We illustrate the usage of our technique by showing how it can be incorporated into digital credentials and anonymous credentials.

Abhishek Sinha

No abstract is available for this record.

Melissa Chase, Markulf Kohlweiss, Anna Lysyanskaya, Sarah Meiklejohn

A signature scheme is malleable if, on input a message and a signature, it is possible to efficiently compute a signature on a related message, for a transformation that is allowed with respect to this signature scheme. In this paper, we first provide new definitions for malleable signatures that allow us to capture a broader range of transformations than was previously possible. We then give a generic construction based on malleable zero-knowledge proofs that allows us to construct malleable signatures for a wide range of transformation classes, with security properties that are stronger than those that have been achieved previously. Finally, we construct delegatable anonymous credentials from signatures that are malleable with respect to an appropriate class of transformations (that we show our malleable signature supports). The resulting instantiation satisfies a stronger security notion than previous schemes while also scaling linearly with the number of delegations.

Alberto Porto, Natalia Porto, Dario Tortarolo

This article examines the relationship between economic integration and fiscal decentralization for Argentina and Brazil. Economic openness adds costs and benefits to fiscal decentralization, beyond those analyzed in closed economies. The relationships among variables with panel data for the period 1988–2005 are estimated. The innovation of the article lies in considering decentralization at the level of states/provinces. In Brazil, the effect of openness on decentralization is negative and significant, both for expenditures and revenues; in Argentina, the effect is negative or not significant. This difference between countries is based on the different structure of subnational government financing.

Padraig Flood, Michael Schukat

With an estimated 50 billion internet-enabled devices deployed by 2020, the arrival of the Internet of Things (IoT) or Internet of Everything (IoE) raises many questions regarding the suitability and adaptability of current computer security standards to provide privacy, data integrity and end entity authentication between communicating peers. In this paper we present a new protocol which combines zero-knowledge proofs and key exchange mechanisms to provide secure and authenticated communication in static machine-to-machine (M2M) networks. This approach addresses all of the aforementioned issues while also being suitable for devices with limited computational resources and can be deployed in wireless sensor networks. While the protocol requires an a-priori knowledge about the network setup and structure, it guarantees perfect forward secrecy.

Asuman Sönmez

2008 yilinda bir makale ile ortaya cikan, 2009 yilinda ilk islemini gerceklestiren bilgisayar algoritmalariyla tasarlanmis Bitcoin, son iki yilda onemli kullanici kitlesi yakalayarak, talebini artirmis, piyasa degerini hizla yukseltmis online bir satin alma birimi ya da sanal para olarak tanimlanabilir. Isminin gercekligi bile supheli anonim bir kisi tarafindan aktif hale getirilen sistemde bir devlet, merkez bankasi gibi klasik para birimlerinin sahip olduklari otoriteler ve garantorler yer almadigi gibi denetim de soz konusu degildir. Islemler network uzerinde direkt olarak iki taraf arasinda herhangi bir araci kurum olmaksizin gerceklestirildiginden maliyeti yok denecek kadar azdir. Sozkonusu durum herhangi bir devlet otoritesinin kontrol ve sorumlulugunun olmamasindan dogabilecek handikaplari da icinde barindirmaktadir. Bununla birlikte sistemin bircok disiplini bir araya getirerek calisan bir yapiya sahip olmasi disiplinlerarasi isbirligi ile ne gibi yeniliklerin ortaya cikabileceginin gorulmesi acisindan oneme sahiptir. Bu calismada; Bitcoin’in dogusu, ozellikleri, Dunya’da ve Turkiye’deki gelisimi ve ekonomisi icindeki yeri, isleyis yontemi arastirilmis, yeni sanal para birimi ile ilgili mevcut durum analizi yapilmistir.

Asuman Sönmez

Bitcoin created as an academic article in 2008 and realized first transaction in 2009 is a digital/electronic currency which is designed on computer and built from calculating an algorithm. It developed rapidly and skyrocketed its market value in last two years by increasing its number of users and demand. The system designed by the pseudonymous person is not depend on neither any government nor a guarantor or an audit institution that the classical monetary system has. The transactions are realizing peer-to-peer network system and the cost of transaction is almost nothing. On the other hand Bitcoin inholds some of problems stemming from its uncontrollable features by any authority such as government, central banks etc. However the system which can be defined as a interdisciplinary study is a good sample in respect of digital innovations. In this study; emerge of Bitcoin, its features, place in World and Turkish economy, transaction methods are researched and worked on a SWOT analysis for new digital currency.

Victor Dostov, Pavel Shust

Purpose – The purpose of the article is to look closely at the phenomenon of the cryptocurrencies such as and bitcoin to identify their potential vulnerabilities to money laundering and financing of terrorism. It also explores their specific characteristics relevant to ML/FT risks. Design/methodology/approach – Using digicash and bitcoin protocols as primary cases for centralized and decentralized cryptocurrencies we analyse their characteristics against cash and cashless payments. We also draw on “bundle of attributes” that may define their attractiveness for common public or criminals. Findings – Our research shows that characteristics of the cryptocurrencies are unlikely to make them popular among the consumers, as demand for anonymity seems to be overrated. Cryptocurrencies can also be classified as payment instrument rather than private currencies; therefore their embededdness in the financial system minimizes the ML/FT risks. Research limitations/implications – Some decentralized cryptocurrencies operate within informal communities. Therefore, relations within these communities are constantly evolving and need to be monitored further. Practical implications – The paper provides an insight into the mechanics and classification of cryptocurrencies as payment instruments. Place of cryptocurrencies within the broader payment ecosystem defines their potential vulnerabilities to being abused by the criminals. Originality/value – The paper fills the gap in research on cryptocurrencies as payment instruments rather than private currencies and also provides an overview of their relevance for the Anti-money laundering and combating financing of terrorism (AML/CFT) regime.

Jeremiah Bohr, Masooda Bashir

Many cryptocurrencies have come into existence in recent years, with Bitcoin the most prominent among them. Although its short history has been volatile, the virtual currency maintains a core group of committed users. This paper presents an exploratory analysis of Bitcoin users. As a virtual currency and peer-to-peer payment system, Bitcoin may signal future challenges to state oversight and financial powers through its decentralized structure and offer of instantaneous transactions with relative anonymity. Very little is known about the users of Bitcoin, however. Utilizing publicly available survey data of Bitcoin users, this analysis explores the structure of the Bitcoin community in terms of wealth accumulation, optimism about the future of Bitcoin, and themes that attract users to the cryptocurrency. Results indicate that age, time of initial use, geographic location, mining status, engaging online discourse, and political orientation are all relevant factors that help explain various aspects of Bitcoin wealth, optimism, and attraction.

Iulian Stănescu

This study features an analysis of the regionalization – decentralization process, on three dimensions: public policy, the relationship over time between decentralization and the development gap between the different areas of Romania, and the public opinion on this issue. The public policy dimension focuses on the content of the regionalization – decentralization process through the analysis of social documents, in this case, the three official documents issued by the Cabinet and parliament. The aim of the decentralization process is a substantial transfer of public services, areas of responsibility and funds from the central Government to the local government – regional, county and local councils. A secondary objective, but with maximum visibility, emerges through the regionalization component: the creation of administrative regions. This entails a change of the territorial administrative structure of Romania and requires a revision of the Constitution. The second dimension of decentralization deals with the results up to this point, as revealed by a longitudinal analysis over more than a 15-year period public financing and development indicators, at national and administrative unit level. During this timeframe, development gaps increased dramatically. Through the mechanism governing local budgets, decentralization acted as a accelerator for increasing inequality. Public opinion represents a third dimension on decentralization. The secondary analysis of a nationwide opinion poll on this issue focused on its notoriety, the general attitude of the population and the public opinion depth of the support for decentralization. The general attitude regarding the decentralization bill could be summed up as conformist and positive. The vulnerability of the support for decentralization comes from several sources, such as: the association with the corruption and “local barrons” metaphor, its lack of priority on the public agenda, and the polarization potential of regionalization.

A Bertrand, Sigrid Aubert, P. Montagne, AC Lohanivo · 5 authors

Les auteurs dressent une rétrospective de la mise en oeuvre de la politique environnementale et forestière 1990-2013 qui repose sur quatre lois, à savoir la Charte de l’environnement (loi 90-033 du 21 décembre 1990), la GELOSE (loi 96-025 du 30 septembre 1996), la loi forestière (loi 97-017 du 8 août 1997) et le Code des Aires protégées (loi 2001-005 du 11 février 2003). Vingt ans après l’adoption de la Nouvelle Politique Forestière, un bilan est possible. Ces textes ont connu un début d’application avec un bilan décevant dans un contexte surtout marqué par une extension de la superficie des aires protégées. Dans le même temps, des évolutions importantes et positives sont apparues. Avec la décentralisation, l’.é.tat de droit s’est construit quotidiennement au niveau des communes à travers les guichets fonciers, les contrats de transferts de gestion et les expériences positives de contrôle forestier décentralisé. Ont également été réalisées des expériences concluantes de valorisation économique des ressources forestières exploitées dans le cadre des transferts de gestion : bois d’oeuvre, bois énergie, raphia, huiles essentielles. Il est donc possible, en novembre 2013, d’envisager de façon réaliste une relance vigoureuse de la politique forestière en tenant compte des invariants comme les faibles effectifs de l’administration et la modicité des financements extérieurs aléatoires. Il est d’abord nécessaire de répondre aux urgences : décrets à publier et à appliquer ; mise en oeuvre systématique des avantages économiques prévus pour les communautés de base signataires des contrats de transfert de gestion. . . . ; sécurisation des espaces communs sous contrats de transfert de gestion. Il faut enfin et surtout faire de la valorisation conservatoire des ressources des produits forestiers ligneux et non ligneux le moteur du développement local.This paper presents a retrospective on the implementation of Malagasy environmental and forest policy between 1990 and 2013 on the basis of four laws, namely the Environmental Charter (Law 90-033 of 21 December 1990), GELOSE (Law 95-025 of 30 September 1996), the Forest Law (Law 97-017 of 8 August 1997) and the Protected Areas Code (Law 2001-005 of 11 February 2003). Twenty years after the adoption of the new forest policy, an assessment is possible. These texts have started to be applied but with disappointing results, primarily centered on the increase of protected area coverage. Nevertheless, important and positive changes have occurred. With decentralization, the reach of the law has increased day by day in communes through land offices, management transfer contracts, and positive experiences of decentralized forest control. Successful experiences of the economic valorization of forest resources (such as timber, fuelwood, raphia palm and essential oils), have also been gained within management transfers. It is therefore possible, in December 2013, to realistically envisage a strong revival of forest policy, even accounting for permanent constraints such as the weakness of the forest administration and the uncertainty of external funding. It is first necessary to respond to urgent needs; to publish and apply un-finalized decrees, to systematically establish the economic benefits anticipated for the community signatories of management transfer contracts, and to secure common property areas within management transfers. Most importantly, the sustainable economic valorization of woody and non - woody forest products should be used as a tool for local development.

Jermain Kaminski

This paper analyzes correlations and causalities between Bitcoin market indicators and Twitter posts containing emotional signals on Bitcoin. Within a timeframe of 104 days (November 23rd 2013 - March 7th 2014), about 160,000 Twitter posts containing "bitcoin" and a positive, negative or uncertainty related term were collected and further analyzed. For instance, the terms "happy", "love", "fun", "good", "bad", "sad" and "unhappy" represent positive and negative emotional signals, while "hope", "fear" and "worry" are considered as indicators of uncertainty. The static (daily) Pearson correlation results show a significant positive correlation between emotional tweets and the close price, trading volume and intraday price spread of Bitcoin. However, a dynamic Granger causality analysis does not confirm a statistically significant effect of emotional Tweets on Bitcoin market values. To the contrary, the analyzed data shows that a higher Bitcoin trading volume Granger causes more signals of uncertainty within a 24 to 72-hour timeframe. This result leads to the interpretation that emotional sentiments rather mirror the market than that they make it predictable. Finally, the conclusion of this paper is that the microblogging platform Twitter is Bitcoin's virtual trading floor, emotionally reflecting its trading dynamics.

Abdu Muwonge, Robert D. Ebel

Provides the basic foundation for understanding intergovernmental finances by (1) discussing why getting municipal finance right remains key to achieving a nation’s broader goals of economic growth, macroeconomic stabilization, and, for some countries, national cohesion among diverse populations; (2) summarizing the key considerations of alternative governance structures, as well as fundamental questions related to what role municipalities should play in a country’s revenue and expenditure systems; and (3) examining the role of government-to-government grants policy and the tools for ensuring accountability between the various levels of government and between the municipality and its citizens. A strong correlation exists between decentralization and growth in gross domestic product (GDP), though findings relating to macroeconomic stability and the relationship between fiscal decentralization and public sector size remain mixed. Case studies from Nepal, Poland, Egypt, Bosnia and Herzegovina, Sudan, South Africa, and Saudi Arabia show the wide variety of decentralization models utilized world-wide.

Lukáš Okruhľanský

Predmetom bakalárskej práce je analýza problematiky virtuálnej meny Bitcoin. Teoretická časť sa zaoberá vysvetlením podstaty tejto virtuálnej meny, jej technickou implementáciou, problematikou bezpečnosti, priblížením právneho hľadiska, ďalej sa praktická časť venuje teoretickému vysvetleniu technickej a fundamentálnej analýzy a približuje aj základy psychologickej analýzy. V praktickej časti je analyzovaný vývoj kurzu bitcoinu od jeho vzniku po súčasnosť prostredníctvom fundamentálnej, technickej a psychologickej analýzy. Napokon sa práca venuje tvorbe predikčného modelu na základe uvedených analýz.

Emil Teșliuc, Lucian Pop, Margaret Grosh, Ruslan Yemtsov

Outlines the institutional and financing arrangements of the last-resort income support (LRIS) programs in seven country cases and distills lessons from the programs’ various approaches to administrative and financial decentralization. The implementation arrangements of LRIS programs in Eastern Europe and Central Asia were shaped, to different degrees, by two factors: (1) the legacy of the social protection systems of the former socialist regimes and (2) the decentralization reforms affecting all transition countries during the 1990s. Most countries in the Eastern Europe and Central Asia region have several tiers of administration involved in the management and implementation of LRIS programs, and in general, the institutional map of the programs is complex. An important issue in almost all countries reviewed in this study is the lack of clear procedures for program administration. Lessons include a prominent warning against decentralized funding, which runs the risk of creating inequities and may lead to serious resource constraints.

Taimur Samad

No abstract is available for this record.