Blockchain Papers

Olivier Blazy, Céline Chevalier, Paul Germouty

No abstract is available for this record.

Pierluigi Cuccuru

No abstract is available for this record.

Michael Reeves

The methodologies used to transfer remittances to Sub-Saharan Africa are currently predisposing their citizens to be dealt unethically large surcharges which are relatively greater than any other location in the world. These African nation's average remittance transaction fees were greater than 13% in 2006 and could become the greatest benefactor if a more efficient methodology of remittance currency transferring were to be created. For instance, if Sub-Saharan African citizens began to utilize cryptocurrencies instead of standard transfer companies like Western Union and MoneyGram; transfer fees could be reduced to as little as (.025%) which would directly send more funds to the people that need it the most. The methodologies within this paper consist of a semi-log poverty regression that utilized an econometric structure similar to the previous literature. In addition to previous regression analyses conducted by Gupta (2009), Giuliano (2008), Adams & Page (2005), and Ravallion (1997); I attempt to include variables in attempt to determine the role that technological integration has towards poverty mitigation. My econometric semi log regression analyzes 18 nations with Africa. These nations were specifically chosen in reference to their relatively large association with remittance transfers. Within this analysis of poverty within Sub Saharan Africa, a strong correlation between remittance transactions and poverty reduction is found. More specifically, the results also suggest that remittances transactions directly assist the most impoverished citizens within a nation most efficiently and that an increased technological infrastructure played a significant role within poverty mitigation. These conclusions should further incentives developing nations across the world to investigate how cryptocurrencies could effectively mitigate poverty.

Christian Cachin

A blockchain is a public ledger for recording transactions, maintained by many nodes without central authority through a distributed cryptographic protocol. All nodes validate the information to be appended to the blockchain, and a consensus protocol ensures that the nodes agree on a unique order in which entries are appended. Distributed protocols tolerating faults and adversarial attacks, coupled with cryptographic tools are needed for this. The recent interest in blockchains has revived research on consensus protocols, ranging from the proof-of-work method in Bitcoin's "mining" protocol to classical Byzantine agreement. Going far beyond its use in cryptocurrencies, blockchain is today viewed as a promising technology to simplify trusted exchanges of data and goods among companies. In this context, the Hyperledger Project has been established in early 2016 as an industry-wide collaborative effort to develop an open-source blockchain. This talk will present an overview of blockchain concepts, cryptographic building blocks and consensus mechanisms. It will also introduce Hyperledger Fabric, an implementation of blockchain technology intended for enterprise applications. Being one of the key partners in the Hyperledger Project, IBM is actively involved in the development of this blockchain platform.

Emanuele Borgonovo, Stefano Caselli, Alessandra Cillo, Donato Masciandaro

No abstract is available for this record.

Zheng Nan, Taisei Kaizoji

No abstract is available for this record.

Joerg Osterrieder, Martin Strika, Julian Lorenz

Cryptocurrencies became popular with the emergence of Bitcoin and have shown an unprecedented growth over the last few years. As of November 2016, more than 720 cryptocurrencies exist, with Bitcoin still being the most popular one. We provide both a statistical analysis as well as an extreme value analysis of the returns of the most important cryptocurrencies. A particular focus is on the tail risk characteristics and we will provide an in-depth univariate and multivariate extreme value analysis. The tail dependence of cryptocurrencies is investigated (using both empirical and Gaussian copulas). For investors¡ªespecially institutional ones¡ªas well as regulators, an understanding of the risk and tail characteristics are of utmost importance. For cryptocurrencies to become a mainstream investable asset class, studying these properties is necessary. Our findings show that cryptocurrencies exhibit strong non-normal characteristics, large tail dependencies, depending on the particular cryptocurrencies and heavy tails. Statistical similarities can be observed for cryptocurrencies that share the same underlying technology. This has implications for risk management, financial engineering (such as derivatives on cryptocurrencies)¡ªboth from an investor¡¯s as well as from a regulator¡¯s point of view. To our knowledge, this is the first detailed study looking at the extreme value behaviour of cryptocurrencies, their correlations and tail dependencies as well as their statistical properties.

Magnus Gausdal Find, Daniel Smith Tone, Meltem Sönmez Turan

Multiplicative complexity is a complexity measure defined as the minimum number of AND gates required to implement a given primitive by a circuit over the basis (AND, XOR, NOT). Implementations of cyphers with a small number of AND gates are preferred in protocols for fully homomorphic encryption, multiparty computation and zero-knowledge proofs. Fischer and Peralta (2002) computed the number of n-variable Boolean functions with multiplicative complexity 1. In this paper, we study Boolean functions that can be constructed with two AND gates. By characterising the structure of these functions in terms of affine equivalence relations, we provide a closed-form formula for the number of Boolean functions with multiplicative complexity 2.

Meilof Veeningen

Pinocchio is a practical zk-SNARK that allows a prover to perform cryptographically verifiable computations with verification effort potentially less than performing the computation itself. A recent proposal showed how to make Pinocchio adaptive (or “hash-and-prove”), i.e., to enable proofs with respect to computation-independent commitments. This enables computations to be chosen after the commitments have been produced, and for data to be shared between different computations in a flexible way. Unfortunately, this proposal is not zero-knowledge. In particular, it cannot be combined with Trinocchio, a system in which Pinocchio is outsourced to three workers that do not learn the inputs thanks to multi-party computation (MPC). In this paper, we show how to make Pinocchio adaptive in a zero-knowledge way; apply this to make Trinocchio work on computation-independent commitments; present tooling to easily program flexible verifiable computations (with or without MPC); and use it to build a prototype in a medical research case study.

Xuechao Yang, Xun Yi, Caspar Ryan, Ron van Schyndel · 7 authors

No abstract is available for this record.

Didi Nuryadin, Sri Suharsih

In the context of financial relations between the central and local governments, the central government has now allocated a Balancing Fund (Dana Perimbangan) to finance local needs in order to support the implementation of decentralization of governance and development as a form of political will to reform and democratize. The aim of this study is to evaluate the effectiveness of DAK allocation for financial year 2003-2013 and to analyze the impact of Dana Alokasi Khusus (DAK) allocation from 2003 to 2013 on various development indicators in the regions (districts / cities). DAK transfer design is the main cause of various issues related to the implementation of DAK. In addition, the problem of DAK allocation mechanisms in the determination of programs and activities, the calculation and use of DAK, budgeting and disbursement of DAK, reporting and monitoring and evaluation of DAK. DAK, as one type of Balancing Fund, has a positive impact on the fiscal capacity of the region, especially the district /city. In addition to regional fiscal capacity, DAK also plays a role in reducing the level of fiscal gap between districts / cities during the period 2003-2007. The result show that DAK allocation (in total) is not significant influence to PDRB per capita of Regency / City. In conclusion, DAK has not had a significant impact on public services and public welfare. This is because the direction of using DAK is not directly used to "build", but only to "maintain". Therefore, DAK is considered not effective enough in an effort to achieve the national priority target.

Vladimir Gužvić, Tarik Čatić, Marina Kostić

OBJECTIVES: The aim of this study was to describe the healthcare system and health financing in Bosnia and Herzegovina and recent trends in health technology assessment (HTA) placement in the system. METHODS: A short review of PubMed published literature has been conducted using key words related to reimbursement, HTA, and health policy. We also revised legislation in Bosnia and Herzegovina published in Official Gazettes related to healthcare financing and organization. RESULTS: A deecentralized system in Bosnia and Herzegovina led to high differences in health policy. HTA has been recognized in legislation in Bosnia and Herzegovina, but it still has not been introduced in practice in full capacity. A small number of publications are found in PubMed treating these issues, but generally the problem of introduction of HTA in Bosnia and Herzegovina is lack of experts, as well as the political environment and education in this field. CONCLUSIONS: HTA in the Federation of Bosnia and Herzegovina and the Republic of Srpska has a short history because of a huge political impact in the decision-making process, decentralized system, and multiple decision makers in these regions. Challenges remain in assessments, in development of more transparent approaches in different areas of the health system in these regions, and in consistent application of appropriate standards especially in education of professionals who will provide establishment of HTA in the health system of The Federation of Bosnia and Herzegovina and the Republic of Srpska.

Navroop K. Sahdev

Blockchain, the technology behind Bitcoin, promises to be nothing less than Internet 2.0. The financial services industry, in particular, is preparing for the disruption blockchain/distributed ledger technology promises to cause. In the current business environment, the majority of startups and small businesses have to look for alternative sources of funding given that ‘going public’ is increasingly expensive. The crowdfunding space has seen tremendous growth as an alternative way to raise capital by businesses. However, these crowdfunded shares cannot be traded for 7-10 years on average on any given platform in the U.S. currently. To build a trading platform on the blockchain which is completely P2P, immutable, fully transparent and low cost presents some key design issues. In particular, the issue of liquidity - and price discovery - on the blockchain continues to be a puzzle. At the same time, the proposition of removing middlemen from equities trading is a very attractive one, streamlining the process of capital formation with higher market efficiency. The current paper addresses the following key questions: How can a DLT trading platform ensure adequate liquidity? What would be the process of price discovery? While some recent studies hail blockchain technology as a boom for market liquidity, it is not immediately clear what the impact of P2P trading would be on the prices of various stocks. There are no ‘solutions’ just yet. At the same time, the lack of regulation around trading on the blockchain creates an environment of uncertainty for all players. In particular, the implementation of such a platform can revolutionize capital formation and build robust markets in both developing and developed countries where crowdfunding has proven to be a successful model. While my research is targeted at solving a very specific pain point for both researchers and companies working on distributed ledger technology, ultimately, it would be a significant step forward towards onboarding underserved communities across the world who don’t have access to financial services.

Daniel Heller

Bitcoin is the first digital currency to have received widespread recognition and interest from users, developers, investors, central banks, and regulators, largely because of its “distributed ledger” technology, which allows it to provide relatively low-cost peer-to-peer transfers of money. Users own the bitcoin system and can make changes to the rules and protocol only by consensus or a supermajority of 95 percent. This communitarian ownership model and the fact that payments in bitcoin can be easily made from one end of the globe to another have led many to believe and hope that bitcoin will one day replace sovereign currencies—and the central banks that issue them. In addition, some observers see bitcoin as the origin of a fundamental transformation of the financial system toward a more decentralized structure. As a medium of exchange, bitcoin is still small compared with traditional channels, and it is held largely for speculation rather than transactions. Its lack of a mechanism for dampening the price effect of an increase in demand or reducing supply in case of a demand slump means that adopting bitcoin as a currency would be like reverting to a currency based on gold coins. As long as central banks continue to pursue stability-oriented monetary policies, they will have little reason to fear that the bitcoin system will replace them.

Boris DDdder, Omri Ross

No abstract is available for this record.

Richard L. Davis

Reviewed by: Negotiated Power: The State, Elites, and Local Governance in Twelfth- to Fourteenth-Century China by Sukhee Lee Richard L. Davis Negotiated Power: The State, Elites, and Local Governance in Twelfth- to Fourteenth-Century China by Sukhee Lee. Cambridge, MA: Harvard University Asia Center, 2014. Pp. xiii + 347. $49.95. For four decades, historians of China’s middle period have tried to run before they walked, ruminating on the evolution of the country’s political and social elites at a macro level before building the necessary foundation in empirical research, especially in the realm of local history. Sukhee Lee’s impeccably researched and deftly executed book delivers a major salvo to prevailing assumptions in the field, while providing alternative ways of reading some of the same texts that informed earlier scholarship. This is the rare book where the footnotes are nearly as meaty as the text itself, due to the author’s tendency to consign his most biting criticism to the notes. Lee addresses elite development at Mingzhou 明州, modern Ningbo 寧波, from the Southern Song (1127–1279) through the Yuan (1271–1368), when the fortunes of Mingzhou’s elite families soared to dizzying heights, in pace with Ningbo’s growing economic and cultural development. This is terrain familiar to me as a political historian of the Southern Song. Court and Family in Sung China, my 1986 book on the Shi of Yin county 鄞縣史氏, examines the crème of the region’s political crop—a lineage that produced three generations of chief councilors, five generations of assistant councilors, and hundreds of lesser officials in the course of two centuries. 1 I knew that my limited focus on the political story would prompt later writers to take up the many social history issues not addressed there, such as kinship organization, marriage strategies, and community leadership. Since then, new primary sources have come to light and archeological discoveries made, including a cluster of several dozen tombs dating from the twelfth to fourteenth centuries in the Ningbo suburbs. 2 At the same time, interest in the wider history of China’s coastal development has been on the rise at home and abroad, especially in Japan. [End Page 227] Robert Hartwell’s seminal 1982 article, “Demographic, Political, and Social Transformations of China, 750–1550” posited a vast chasm between the Northern Song (960–1127) and its successor in the south. His argument presented the elite devolving from its primary focus on political office to a narrow concern with local activities and networks, a trend that continued into the Yuan and early Ming (1368–1644). As the imperial imprint shrunk, the upper classes became increasingly autonomous and self-perpetuating, while the state’s involvement with local society declined. And the examination degree, rather than providing the path for official advancement, became merely a marker of social status. 3 Hartwell focused on marriage networks and community activism in particular to identify the “localist strategies” of the twelfth and thirteenth centuries. He also pointed to certain institutions as markers of this trend toward decentralized governance during Southern Song times, including the Grand [fiscal] commissariat (zonglingsuo 總領所) (p. 14). Unfortunately, Hartwell’s strengths as an economic historian often proved his greatest weakness when venturing into social and political history. A succession of Hartwell students at the University of Pennsylvania would attempt to apply his thesis to individual locales starting from the late 1970s, including Hugh Clark, Paul Smith, and Linda Walton-Vargo, but his most industrious acolyte is Robert Hymes, author of two books on Fuzhou 撫州, Jiangxi, books loyal to the overall outlines of Hartwell’s work. 4 Hymes also coedited a symposium volume on the “Song–Yuan transition,” while Smith coedited a volume on the “Song–Yuan–Ming transition.” 5 I have long referred to the group as the “Penn School,” though it has expanded to include Columbia University, where Hymes has taught for the past three decades and has produced students with similar interests. Later, Peter Bol at Harvard University, the adviser of Sukhee Lee, the [End Page 228] author of the book under review, succumbed to the sway of Hartwell, whose argument about elite evolution dovetails nicely with Bol’s own work in intellectual history. In “This...

Тетяна Майко

Thesis is devoted to scientific and theoretical explanation of the City Council functioning as an institution of local democracy in Ukraine. It is defined that in political foreign science, investigation of democracy institutions on the local level has its own tradition. In Ukrainian political science, there are two ways of the City Council investigation as an institution of local democracy. The first group of Ukrainian scientists carries out scientific researches devoted to the problems of the City Council institutional development. Another group of scientists discloses outlined problems due to the regional research. Researchers’ attention is paid on subjects of political process in regions. But the problem of lack amount of applied research, particularly devoted to the analysis of political practice in the interaction between the City Council and community, still exists. On the basis of analysis, generalization and systematization of scientific resources, the state of scientific research on the problem of local democracy institutions in Ukrainian literature, is highlighted. Basic methodology approaches of modern political science to the understanding of the City Council as an institution of local democracy are defined. It is proved that the research of methodological principles of the City Council as an institution of local democracy study requires a combination of several aspects. It is important to take into consideration that the City Council operates on the lowest territorial authorities’ level. Its main characteristics are autonomous authority formation from another administrative units and combination of representative direct forms of democracy and citizen participation in political process. The City Council is not only a form of state decentralization, but also a mechanism of social and political regime. As a result of interaction evolution between the City Council and community, institutions of local democracy which legalize their activity on certain territories and have a certain level of trust in society are established. The principles of subsidiary as a factor of system transformation of local selfgovernment in Ukraine. It is important to use the principal of subsidiary during the interaction between the City Council and community. It is found out that the mechanism of solving important problems on the level of their occurrence is necessary for democratization of Ukrainian political process. Special attention is paid on political and legal regulation of community participation in the process of local democracy through the prism of public authority functioning. It is proved that Ukraine has a powerful legislative framework for local democracy institutions functioning. It is found out that there are enough legislative basis for local democracy institutions functioning, but the problem of lack amount of mechanisms to regulate community participation in the processes of local democracy exists. Regulatory and legal framework in Ukraine defines basic powers of the City Council and its executive bodies in the sphere of its regulation. It doesn’t usually establish the procedure of these powers realization. That is why, procedural norms should be prescribed in the City Council’s legal documents (statutes, regulations) and their compliance will provide political and legal basis for interaction between the City Council and community. It is proved that the essence of reformation in the legal field depends on the City Councils empowerment concerning solving their vital problems, increasing their economic independence, optimizing the distribution of powers between local authorities and the City Councils and as a result ensuring required quantity and quality of social and administrative services for Ukrainian citizens.It is stressed on the fact that democracy and society take their beginning from community and the City Council is an important element of local democracy and society. At the same time, community is a solid foundation of society development. The City Council should meet community interests and needs. It is necessary in the case of spheres and competences division between state authority and the City Council on the principles of subsidiarity and political responsibility. It is found out that community performs protection, management, coordination and regulation functions on certain territories. Community can be defined as a certain community which is united within one territory in order to solve common political, economic, social and religious problems. It is explained that political management in the community should be realized concerning local population interests, development and territory conversation on the basis of efficient use of community resources. It is mentioned that the City Council needs certain bodies of community self-organization to diagnose community problems, attract additional resources for solving social problems and advocate community interests before state government. The attention is focused on the functions of community self-organization bodies: satisfying social interests and needs, informing authorities of their problems and needs, realization of public control over the City Council activities, assistance in solving common community problems. It is stressed that community self-organization bodies are a part of civil society and a system of local self-government that mobilize residents to solve their home, street, square and region problems. Bodies of community selforganization can be financed from the local budget and use their resources on their purposes within law determined by the City Council and accepted solution of community general meetings’ members. The peculiarities of public control in the City Councils are shown. It is mentioned that public control is becoming an important factor in the process of decision making on the local level. Public control has its own characteristics. Control itself is realized by community (organized, unorganized) and in the process of its realization, community controls authority’s implementation of its social obligations. It is observed a tendency of communication activation between the City Council and community through the system of electronic petitions. The problem of trust between subjects of local democracy realization (state and community) is very topical when we talk not only about using funds, but openness and responsibility for decision implementation as well. The efficiency of public control should take into account two levels of evaluation. The first level concerns public opinion. The second one – processing of local decisions among experts. To solve the most topical problems of local community life, we should understand how these main forms of local democracy as local initiatives, general meetings, local referendums, public hearings and activities of community self-organization bodies were used. It is mentioned that an important part of the City Council democracy understanding in Ukraine is the index of publicity. Measuring this index, we can understand how open political decision making on the local level is and what involvement of local policy subjects in this process is. It is mentioned that the index of publicity contains an integrated system of indicators which give a possibility on the regularly basis to evaluate and compare the quality of bodies and local officials’ governance in the context of their activity. Defining the index of the City Council publicity, it is important to take into account such criteria as: the existence of community statute and the City Council regulations; the existence and analysis of local initiatives; public hearings and public expertise; mayors and the City Council deputies reports; general meetings of citizens; electronic petitions; public consultations. These criteria give a possibility to define the level of the City Council publicity in Ukraine. In order to increase the level of community social involvement, the state has to become an active participant in common projects devoting to partnership development among public organizations, bodies of local self-governing and community in the sphere of services provision. To implement community initiatives, it is necessary to monitor the compliance with the community rights law on realization of direct democracy mechanisms. It is stressed on the fact that internal and external factors influence on the realization of community initiatives on the City Council level. The first group of factors contains objective conditions, such as: peculiarities of political regime transformation; social and economic state development; specifics of state policy implementation and powers division between the center and regions; state of legal and regulatory functioning framework of such organizations. Among internal factors, subjective conditions can be distinguished: level of local institutional development of local democracy institutions; presence of real leaders in this organizations; existence of necessary resources (political, economic, social, demographic etc.) for policy implementation.

Ayala Grefa, José Luís

The design of the hostel will be located in a privileged area, it will be a company that will strengthen tourism as it has catering and accommodation services, becoming important activities to increase tourism in Tena Canton, helping to promote new jobs for society and generating direct and indirect income. This project will allow to know and describe the existing natural, human and physical resources within the study area that are of vital importance for the development of the project, as well as identifying some needs that the area has. Four objectives were set in the project: The first objective: To diagnose the current situation of the study area, it was possible to gather information through field work and bibliographic research, necessary data that were systematized through the use of the following techniques: Inventory and ranking sheets of tourist attractions prepared by the Ministry of Tourism. In the diagnosis, the following data were taken into account: General, economic, population, culture, education, tourist attractions, tourist facilities, basic services, roads, among other characteristics of the Canton. For the second objective: a market study, the analysis and interpretation of 10 questions prepared and designed with different questions related to the topic was carried out, which were reflected in a survey answered by 144 people, represented by 57% of the inhabitants of the place, 33% by national tourists and 10% by international tourists, supply and demand were analyzed in which an explanation of the direct competitors was made, the profile of the visitor was determined, their tastes and preferences, detailed explanation of the SWOT in their respective nuances for know their strengths, opportunities, weaknesses and threats, proposing strategies for the use of the products and services offered. The third objective: Technical study, taking into account important aspects of the company such as; name, executive summary, description of the business, vision, mission, objectives, value, logo, slogan, organizational structure of the company, functions that employees must meet, flow of the productive process of food and lodging, architectural design and advertising important aspects 5 that allowed to establish the operability of the research achieving optimal results. The fourth objective: the financial study. The financial study takes into account labor, fixed assets, deferred assets, current assets or working capital, depreciation, amortization, financing, total costs, classification of costs, income, profit and loss statement, point of equilibrium, cash flow, RBC (1, 39), VAN (26790.73), IRR (13.92), PRC (4.69) and sensitivity analysis. In the research work methods were used, such as analytical, synthetic, inductive and deductive through which the respective conclusions and recommendations could be elaborated. The techniques used were the observation in situ, to collect necessary information and establish the current reality of the canton. The research formulates the conclusions and recommendations as well as highlighting the total support from the municipal GAD to promote this proposal. It is recommended that the Tena Municipal Decentralized Autonomous Government promote tourism activities and promote dissemination and promotion.

Quezada Cruz, Miryam de Lourdes

The present thesis project has as general objective to make the diagnosis and proposal for the elaboration of a manual of valuation of positions for the workers of the Autonomous Government Decentralized of the Province of Sucumbios during the year 2015, that allows an efficient Administration in the GAD, To fulfill the purpose it became necessary to use the deductive, inductive and bibliographic methods, within the techniques used was conducted direct observation and the survey to 347 workers who are under the labor law of the Organic Law of Public Service, the same as Allowed to gather information about the development of human talent. In the results, a Situational Diagnosis was carried out, analyzing the History of the GAD, the current organization, the business philosophy, the location, the services it provides and the departmentalization. Subsequently, the tabulation and interpretation of data was done to the staff survey to propose the manual of functions for the 59 positions governed by the Labor Code. In addition, the valuation of posts was elaborated, where the points system was applied with its respective stages from the definition of factors to the valuation of jobs, where the following results were obtained: the total of points according to the valuation is 17,830, the Salaries received by GAD employees amounts to $ 40,389.35, with these data the straight-line equation was applied which resulted in a slope of 2.21, based on the aforementioned value, the salary adjustment was made with An upgrade factor of 2.27, in order to determine the new wages. It should be noted that the valuation was performed that were below the salary adjustment line, which totaled 31 positions and they are: Sailor, Garden Assistant, Welder's Assistant, Motorist's Assistant, General Service Assistant, Service Assistant Maintenance Assistant, Chaspitero Assistant, Technical Assistant and Workshop Assistant, Chaspitero, Worker, Driver, Plumber, Guard, Machinery Assistant, Warehouse Assistant, Operator, Mechanic Assistant, Asphalt Plant Assistant, Safety Inspector, Operator Barge, electrical assistant, engineering assistant, topography assistant, chauffeur, tanker assistant, warehouse assistant, lab assistant, caddy, electromechanical, dump truck driver and track assistant. Finally the conclusions and recommendations of the work are presented being the most relevant that the human talent that works in the provincial GAD of Sucumbios do not know the tasks or functions of the position and the requirements that the position requires and as far as refers to the recommendations is suggested Consider the GAD job evaluation manual, in order to systematically assess the performance of the staff in charge, which will determine if it meets the requirements that are required to fill the different positions.

Nazmul Islam, Kazi Md. Rokibul Alam, Shinsuke Tamura, Yasuhiko Morimoto

This paper proposes a new electronic voting (e-voting) scheme that exploits confirmation numbers (CNs) and revised simplified verifiable re-encryption mixnet (R-SVRM). R-SVRM is a recently introduced mechanism of mixnet also used to develop an e-voting scheme where a vote is decomposed to protect its voter from being coerced to cast a particular vote. Though the scheme avoids complicated zero knowledge proof (ZKP), the verification procedures of its cryptographic operations are still cumbersome. Again, another e-voting scheme based on CNs comes with benefits of vote verifiability and unlinkability between the vote and its voter, lags behind in adopting public keys for encryption and signature verification. Also its exploited mixnet is not verifiable; therefore requires a pair of signatures on each encrypted vote to ensure the verifiability of mixnet. Hence, the computation and communication overhead of the scheme becomes weighty, though ZKP is avoided. In contrast, the proposed scheme deploys both CNs and R-SVRM to eliminate these limitations. Hence, any coercer cannot force the voter to cast a specific vote as well as cryptographic operations and their verifications become simpler. Also the computation and communication overheads for involved entities get decreased. Finally, the security requirements of e-voting are achieved more elegantly.

Daniel Genkin, Yuval Ishai, Mor Weiss

No abstract is available for this record.

Wulf A. Kaal, Craig Calcaterra

No abstract is available for this record.

Dominik Krause, Nga Pham

Bitcoin is a peer to peer (p2p) payment cash system and an unregulated digital currency that is primarily designed and developed in 2008 without tender legal status. Bitcoin is so-called cryptocurrency because it uses the cryptographic function in order to secure the creation and transfer of money. During recent years, Bitcoin has been emerging as the well-known electronic currency and gaining popularity worldwide as well as caught the media attention in the area of volume trading. Therefore, Bitcoin will be a potential financial asset for investors due to its extraordinary returns. The purpose of this research is to find out how Bitcoin returns correlate with stock markets and to assess the risk that the electronic currency bears, to conclude whether Bitcoin is a favourable instrument for investors that want to diversify their portfolios. Therefore, daily data from 2013 to 2017 is used to measure correlations with major global stock markets and analyse in a regression to what extend Bitcoin is integrated into financial systems. In addition, Bitcoin’s risk has been measured by estimating value at risk, as well as the volatility and a regression analysis with explanatory variables has been performed to identify the driving factors of the unusually high volatility. Finally, the researchers constructed models to forecast expected returns to identify whether Bitcoin is rather a short or long term instrument. The researchers came to the conclusion that Bitcoin is a favourable instrument to diversify a portfolio as it correlates negatively with most of the analysed stock market indices and the research result showed that Bitcoin is not yet integrated into financial systems. It has however been paid attention to the new types of risk and the questionable image the electronic currency has as it is often used to support criminal activities. The fact that no authority, clearing house or central bank's involvement is present, creates uncertainty for many investors.

Christoffer Koch, Gina Pieters

This article gives a very general introduction to the technology, promises and limitations of blockchain technology --- popularized by the digital currency Bitcoin and a key force behind the surge of cryptocurrencies. Blockchain acts as a distributed database or joint global register of all transactions --- a decentralized digital ledger --- and has the potential to become a disruptive force in the financial industry and elsewhere, bypassing traditional, centralized channels such as banks.