Blockchain Papers

Hisham S. Galal, Amr Youssef

No abstract is available for this record.

Antonio Welligton Abreu

Blockchain is considered an emerging technology, having aroused the interest of researchers
\nand industries on the world stage. After the success of this technology in the financial market
\nwith virtual currencies (such as Bitcoin and Litecoin), blockchain starts to be used by different
\ndomains, such as government and education, as it provides a reliable, scalable and immutable
\ndistributed environment for the realization and storage of transactions on a network. Smart
\ncontracts are one of the features of the Ethereum blockchain, which has the ability to run a
\nprogramming model for applications distributed in untrusted environments. These contracts
\nreside on the blockchain and enable process automation in several stages. Smart contracts have
\nbecome one of the most sought-after technologies due to the high customization they add to
\ntransactions, allowing to seek blockchain-based solutions to problems in industry and academia.
\nHigher education is a system with several challenges that can be solved with the adoption of
\nthis technology. Protecting data transactions involving student degrees is one of the challenges
\nconsidered by educational institutions. Thus, this work presents an architecture proposal based
\non blockchain technology to store and consult data from diplomas issued by higher education
\ninstitutions. Through this architecture, a new approach for the validation of diploma data with
\nthis emerging technology was evaluated. As a proof of concept, a prototype of the environment
\nwas implemented using smart contracts based on the Ethereum platform. After implementation,
\nan evaluation was carried out with specialists in the management of diplomas and an analysis
\nof the performance of the transactions carried out in the prototype was carried out. In view of
\nthe results obtained, the proposal proved to be adequate to the process of storing and consulting
\ndiploma data.

Juuso Ahtinen

The purpose of this thesis is to study the predictability of cryptocurrency returns by investor attention, the interconnections of the cryptocurrency market, and what causes attention to cryptocurrencies. This is done by examining Bitcoin, Ethereum and Ripple which are the three biggest cryptocurrencies by market capitalization in January 2020. The dataset is constructed from weekly returns, weekly changes in investor attention measured by Google trend data and weekly changes in average weekly trading volume between years 2016 and 2019. The empirical analysis is conducted by performing OLS regressions, vector autoregressions and Granger causality tests. Additional robust tests are conducted by dividing the sample in pre-bubble and post-bubble samples adding all of the investor attention proxies to individual Cryptocurrency regressions. The results suggest that the market phase for a cryptocurrency affects the predictability of returns as the statistically significant positive relationship between investor attention disappears in the post-bubble sample for Bitcoin and Ethereum but endures for Ripple in both samples. This provides more evidence for the earlier findings that cryptocurrencies become more efficient as the market matures. The interconnections of the cryptocurrency market are shown to exist as the returns of Bitcoin drive investor attention to Ripple which is shown to be a significant predictor for all of the three cryptocurrencies in the whole sample. The spillover effect is shown to take time confirming earlier findings and unfolding the herding effect via investor attention in cryptocurrencies. Additionally, investor attention is shown to be caused by earlier returns for the cryptocurrency as well as the returns of Bitcoin. These results explain the interconnections of cryptocurrencies, the changing market dynamics in the cryptocurrency market, and the predictability of cryptocurrency returns by investor attention.

Afees A. Salisu, Ahamuefula E. Ogbonna, Tirimisiyu F. Oloko

This study examines the effect of a pandemic-induced uncertainty on cryptocurrencies (specifically, Bitcoin, Ethereum and Ripple). It employs a predictive model by Westerlund and Narayan (2012, 2015) to examine the predictability of a pandemic-induced uncertainty as a predictor, as well as the forecast performance of our predictive model for cryptocurrency returns. We examine the role of asymmetry in uncertainty and the sensitivity of our results to alternative measures of uncertainty due to pandemics, using the recently developed Global Fear Index (GFI) by Salisu and Akanni (2020). Our results indicate that cryptocurrencies could act as hedge against uncertainty due to pandemics, albeit with reduced hedging effectiveness in the COVID-19 period. Accounting for asymmetry is found to improve the predictability and forecast performance of the model, which indicates that failure to account for asymmetry in modeling the effect of a pandemic-induced uncertainty on cryptocurrency may lead to incorrect conclusion. The results seem to be sensitive to the choice of measure of pandemic-induced uncertainty.

Moin Hussain Moti, Dimitris Chatzopoulos, Pan Hui, Boi Faltings · 5 authors

No abstract is available for this record.

Carlos Pinzón, Camilo Rocha, Jorge Finke

A blockchain is a distributed hierarchical data structure. Widely-used applications of blockchain include digital currencies such as Bitcoin and Ethereum. This paper proposes an algorithmic approach to analyze the efficiency of a blockchain as a function of the number of blocks and the average synchronization delay. The proposed algorithms consider a random network model that characterizes the growth of a tree of blocks by adhering to a standard protocol. The model is parametric on two probability distribution functions governing block production and communication delay. Both distributions determine the synchronization efficiency of the distributed copies of the blockchain among the so- called workers and, therefore, are key for capturing the overall stochastic growth. Moreover, the algorithms consider scenarios with a fixed or an unbounded number of workers in the network. The main result illustrates how the algorithms can be used to evaluate different types of blockchain designs, e.g., systems in which the average time of block production can match the average time of message broadcasting required for synchronization. In particular, this algorithmic approach provides insight into efficiency criteria for identifying conditions under which increasing block production has a negative impact on the stability of a blockchain. The model and algorithms are agnostic of the blockchain’s final use, and they serve as a formal framework for specifying and analyzing a variety of non-functional properties of current and future blockchains.

Andreas Masuhr, Mark Trede

Abstract This paper proposes a Bayesian estimation algorithm to estimate Generalized Partition of Unity Copulas (GPUC), a class of nonparametric copulas recently introduced by [18]. The first approach is a random walk Metropolis-Hastings (RW-MH) algorithm, the second one is a random blocking random walk Metropolis-Hastings algorithm (RBRW-MH). Both approaches are Markov chain Monte Carlo methods and can cope with ˛at priors. We carry out simulation studies to determine and compare the efficiency of the algorithms. We present an empirical illustration where GPUCs are used to nonparametrically describe the dependence of exchange rate changes of the crypto-currencies Bitcoin and Ethereum.

Moa Hermansson

Banking is considered only one of many industries that could benefit from using blockchain technology. A promising area in blockchain technology is so-called smart contracts, which is automated, decentralized and programmable contract solutions. Smart contracts can control the transfer of currencies or assets between parties under given conditions. The thesis work shows how blockchain technology could be applied to real estate transactions and minimize the need for third party involvement. The purpose of this paper is to provide an overview of the blockchain technology and its possible applications in the real estate market. The focus was on exploring the process of real estate transactions and problems that could be resolved by using smart contracts and blockchain technology. Witha qualitative research approach and a case study analysis, a proposition of a solution was made and discussed with its benefits and drawbacks. The goal was to in the process find the answers for the research questions such as: How can real estate transactions benefit from blockchain technology? What would it cost to store the necessary data on the main chain of Ethereum? How could blockchain technology be used for managing the transaction of the down payment? Even though a collaboration of systems and smart contracts could handle almost every aspect of a real estate transaction, there are still legal boundaries to it being legally enforceable. The blockchain technology could contribute to more efficient and transparent systems compared to traditional centralized solutions.

Fan Yuan

The phenomenon of isolated value in each blockchain system has become adistinct issue of the blockchain field. To address this problem, the demandof cross-chain intercommunication came up. In a narrow sense, cross-chainrefers to the process of asset interoperability between relatively independentblockchains. In this thesis, we mainly analyze the design principles, technicaldifficulties, and solutions of cross-chain intercommunication in this narrowsense. With the introduction of distributed ledger technology(DLT), we describethe interaction with other ledgers as the fundamental problem of currentblockchain technology.The implementation of cross-chain is mainly manifested as asset swap and assettransfer. So far, there are many existing application scenarios and projectsadopted from these manifestation. This paper will focus on these two implementations,illustrate their principles, locate the realization difficulties, andput forward corresponding possible solutions. Then we elaborated on eightpopular cross-chain projects underlying mechanism listed with three maincategories. A detailed comparison according to their interoperability level,consensus algorithm and application scenarios of the overall overview of 20cross-chain projects is presented as a table in the Appendix A.During the implementation process, we performed a simple atomic swap crosschainframework based on Hash Time Lock Contract between Bitshares andEthereum, then compare the performance with a wallet application presentby Ripple using Interledger Protocol. These two applications are representedthe two different use case of cross-chain realization.With limited number of projects to test out, our conclusion was reached aftera discussion with the relative merits of the two approaches. Interledger protocolhas a better solution from the aspects of the decentralization, scalability,and whether it supports traditional ledgers.

Faiza Loukil, Chirine Ghédira, Benharkat Aïcha-Nabila

No abstract is available for this record.

Eric D. Chason

Having recently celebrated its ten-year anniversary, Bitcoin should be considered a qualified success. In October 2020, each unit1 was worth about $10,700, and the entire market capitalization was approximately $200 billion.2 Bitcoin is a significant economic force with sizable market value. Despite this success, however, Bitcoin has not been widely adopted as a method of payment, which was its intended use.3 By providing a template for a durable cryptocurrency, Bitcoin also blazed a path for other cryptocurrency projects. In terms of market capitalization and current importance, Ethereum is comfortably in second place.4 In October 2020, it had a market capitalization of approximately $40 billion.5 Unlike Bitcoin, however, Ethereum was not designed primarily to serve as a method of payment. Ethereum supports a system of sophisticated “smart contracts” that would not work on the Bitcoin system. Smart contracts and cryptocurrencies have sparked considerable interest among legal scholars in recent years, and a growing body of scholarship focuses on whether smart contracts and cryptocurrencies can sidestep law and regulation altogether.6 Bitcoin is famously decentralized, without any central actor controlling the system. Its users remain largely anonymous, using alphanumeric addresses instead of legal names. Ethereum shares these traits and also supports smart contracts that can automate the transfer of the Ethereum cryptocurrency (known as ether). Ethereum also supports specialized “tokens” that can be tied to the ownership of assets, goods, and services that exist completely outside of the Ethereum blockchain. The goal of this Article is to evaluate the degree to which cryptocurrencies and smart contracts can operate outside the reach of law and regulation. By some accounts, cryptocurrencies and smart contracts will revolutionize private law.7 Some argue they have the potential to displace contract and property law. For example, in a previous article, I argued that Bitcoin represents a system of private property that exists wholly outside of traditional legal structures.8 In this Article, I will argue that a complete revolution is not inexorable.9 Facing the technical and complicated nature of this subject, we should keep in mind a simple fact: cryptocurrencies and smart contracts are computer data and computer programs. To a large extent, they will have legal force only if given force by judges, regulators, and legislators. Part II describes Bitcoin and how it creates a system of property that exists outside of legal structures. Bitcoin is special because it controls no external assets (like securities, dollars, or gold). It is purely “notional” property that exists only on a computer file. Part III describes Ethereum and how it builds upon the principles of Bitcoin. The primary innovation of Ethereum is smart contracts, which allow for variable and conditional transfers of cryptocurrency. To be of commercial value, however, smart contracts must incorporate economic or financial information (e.g., interest rates or exchange rates). Ethereum allows users to incorporate this information using third party “oracles.” While oracles allow for sophisticated transactions, their presence illustrates some of the limits of smart contracts. Part IV extends the discussion of Ethereum and explains how many developers use it as a way to effectuate property transactions. Tokens are specialized smart contracts used to represent ownership of assets or certain privileges. Conceivably, ownership in any asset— homes, cars, etc.—could be represented by Ethereum tokens. Rather than using a deed of transfer, owners could simply transfer the representative tokens. Part V develops what this Article calls a “remote-computer model” of Bitcoin and Ethereum. Because Bitcoin and Ethereum are computer programs and computer data, we can view each as constituting a single computer. This hypothetical computer is remote in the sense that judges, regulators, and legislators can exercise little control over it directly. The remote computer controls ownership of cryptocurrency units, leaving direct cryptocurrency transactions outside the scope of traditional legal institutions. That being said, smart contracts often purport to control external resources and rights. For example, a smart contract might purport to control the transfer of land or stock in a corporation. These transactions have effects outside the hypothetical remote computer and can potentially be subject to control by legal institutions.

Donal O’Mahony, Sijia Zhao

The emergence of e-commerce has changed the way people trade. However, merchants are charged high fees for their use of the platform and for payment services. These costs are passed on to customers in the form of higher prices. Blockchain technology can provide lower transaction fees with high security and privacy level but is incapable of delivering the number of transactions per second demanded by real e-commerce. Establishing a layer above the blockchain to manage transactions which we called Blockchain Layer2 technology, has the potential to solve these issues. In this article, we focus on the effect that layer2 technology can provide in reducing fee costs and improving transaction volumes. We introduce the problems that the e-commerce industry is facing currently and how blockchain layer2 technology can help to address these issues. We list and describe the main layer2 mechanisms based on the Bitcoin and Ethereum blockchains. We discuss issues that arise when applying layer 2 technology to e-commerce. We analyse the costs associated with difference e-commerce payment network topologies and investigate the funds-capacity needed to support high levels of value transfer.

Oleksii Konashevych

The blockchain is a technology that was initially designed as an alternative to the banking system aimed to decentralize money circulation. It has become apparent that the invention has a vast potential to improve various industries and fields of human activities. The blockchain industry generated a variety of ideas of how to use this technology: to crowdfund business with Initial Coin Offerings (ICO), to tokenize and manage assets online, to improve public administration and state-owned registries, or even to use it for electronic voting. Multiple applications of this technology became possible since the industry started experimenting with overlay technologies on blockchains, for example, Colored Coins, known as tokens on Bitcoin; Namecoin, a blockchain as a decentralized infrastructure for Top-Level Domain “.bit,” but the significant step forward happened when Ethereum proposed their concept of smart contracts on blockchain. There are several platforms that offer users the ability to design their own private and public distributed ledgers (Hyperledger, Azure). It is not easy to mention all of the projects in the field of blockchain industry; however, at this stage, it has become clear that the technology (along with some other innovations, like Artificial Intelligence) is penetrating spheres that are traditionally highly regulated and centralized with a high level of human participation: securities and exchanges, public registries (notary, real estate, business entities and other registries), public finances, elections, etc. This discussion is devoted to the issues of regulations for the activities that arise from the blockchain.

Marin Thiercelin, Chen-Mou Cheng, Atsuko Miyaji, Serge Vaudenay

By design, smart contracts' data and computations are public to all participants. In this paper, we study how to create smart contracts with parameters that need to stay secret. We propose a way to keep some of the parameters off-chain, while guaranteeing correctness of the computation, using a combination of a commitment scheme and a zero-knowledge proof system. We describe an implementation of our construction, based on ethereum smart contracts and zk-SNARKS. We also provide a small example and a cost analysis of our approach.

Taurai Muvunza

No abstract is available for this record.

Jiahao He, Guangyuan Zhang, Jiheng Zhang, Rachel Zhang

No abstract is available for this record.

Yinan Pei, Kazumasa Oida

The Onion Router (Tor) is one of the major network systems that provide anonymous communication and censorship circumvention. Tor enables its users to surf the Internet, chat, and send messages anonymously; however, cyber attackers also exploit the system for circumventing criminal activity detection. Recently, various approaches that prevent or mitigate abuse of Tor have been proposed in the literature. This paper, which presents one of the approaches, addresses an IP traceback problem. In our model, onion routers that voluntarily participate in attacker tracing detect attack packets (packets carrying an attacker's code or data) recorded in the log files by sharing necessary information with an attacked server over an Ethereum blockchain network. The detection algorithm in this paper uses the statistics of packet travel and relay times and outputs attack-packet candidates. The proposed method attaches a reliability degree to each candidate, which is based on the upper bounds of its Type I and II error rates. A smart contract running on the blockchain network ranks the detection results from onion routers according to the reliability degrees.

Tushar Dhiman, Vidit gulyani, Bharat Bhushan

No abstract is available for this record.

Blaž Podgorelec, Marjan Herieko, Muhamed Turkanović

Currently, developers and researchers are dedicated to finding better ways to achieve greater scalability of various blockchain platforms. Focused on the Ethereum blockchain platform, the state channels are currently the only maturely researched and implemented a solution for achieving scalability. However, there are still several problems, such as transparency of state channel networks, transaction traceability, and the incapability that the off-chain state is transferred back on the blockchain network in an ad-hoc manner. To solve the aforementioned problems, we propose a novel state channel solution in the form of a State Channel as a Service, which, although off-chain, still incorporates a secure distributed and decentralized network. This solves the challenge of transparency and traceability while giving users the confidence that only the valid last off-chain state is transferred back on the blockchain network. With the proposed solution, there is no need for users to monitor state channel activities for possible malicious actions. Implementation was performed in the form of a payment channel system, presenting a potential use case for the SCaaS. Furthermore, we performed a security and performance analysis, which shows that the solution is secure and by a factor of 12 more efficient than the classical on-chain payment systems. To evaluate and prove the contributions of the proposed solution, quantitative, and qualitative comparisons with selected related works (i.e., Raiden and Celer) were also performed.

Ayana T. Aspembitova

Decentralized Finance is the new socioeconomic system growing with an extremely fast pace and changing the way financial interactions are being conducted. In comparison with the growing importance of digital assets and blockchain technology, there is still little understanding of Decentralized Finance as a system. In this thesis we analyze transaction datasets from Bitcoin and Ethereum blockchains to obtain a comprehensive understanding of digital assets -from studying the behaviour of each part to investigating the whole structure and deriving the relations between micro and macro properties of the cryptocurrency systems. Using the Complex Networks approach we explained the system's overall structure and dynamics, and uncovered the mechanism behind network formation. It was found that there is fitness preferential attachment among nodes in the bitcoin network that leads the system to scale-free behaviour. We proposed the quantifiable definition of fitness and supported our finding by simulating a synthetic network and reproducing the main properties of the bitcoin network. After having a good understanding about the structure of the system, we zoom in into its parts by studying the behavioral patterns among the system's users (people). We develop the methodology based on Machine Learning models to define distinct behavioral types in the cryptocurrency systems and find that despite differences between the bitcoin and ethereum systems, there are four common strategies that users follow in both markets. Based on our finding, we model the dynamics of people's behaviour in market as an Absorbing Markov Chain. This approach allowed us to present the behavioral switches in a comprehensive and intuitive way. Moreover, we were able to obtain the predictions on the longevity of users in the system according to their behaviour. Finally, we use the Granger causality test to derive the relations between all system characteristics. We attempt to explain the effect of behavioral switches on the structural properties and price; we find that indeed, switches of users from certain behavioral groups causes a change in price which affects the size of the network as well. We hope that the work and results presented in this thesis will advance the understanding of the new field of Decentralized Finance and expect that the research approach and methodologies developed for this study will be helpful to investigate various complex systems as well.

Asma Khatoon

WHO was informed on 31 December 2019 of cases of unknown cause pneumonia in Wuhan City, China. On 7 January 2020 Chinese authorities reported a novel coronavirus as the cause and was temporarily labeled "2019-nCoV." Coronaviruses (CoV) are a wide family of viruses which cause diseases ranging from common cold to more serious illnesses. A novel coronavirus (nCoV) is a new strain not previously found in humans. Countries around the globe have stepped up their surveillance to quickly detect any new 2019-nCoV cases. Blockchain is developing into a safe and efficient network for secure data sharing in applications such as the financial industry, operations management, food industry, energy market, the Internet of Things and healthcare. In this paper, we are using blockchain technology as a mean to share authentic data, tracking of relevant information and help speed up the treatment process. At the same time it will preserve person’s identity. Timely deployment and suitable implementation of the proposed model have the opportunity to curb COVID-19 transmissions and associated mortality, especially in environments with inadequate access to testing facilities. This work will also facilitate in the treatment of other infectious diseases. Smart contract have been designed and implemented using the ethereum blockchain platform which has been presented in this paper. This work would facilitate multiple stakeholders who are involved within the medical system to curb the transmission of this disease.

Ashwini Chaudhari

Blockchain and cryptocurrencies have risen to popularity in the recent years to a great extent due to its increasing trading volumes and huge capitalization in the market. These cryptocurrencies are being used not only for trading but are being accepted for monetary transactions as well these days. As the prices fluctuate and return on investment increases investors, traders and general public are showing increased interest towards bitcoin and altcoins. This research focuses on implementing forecasting models that will return accurate price predictions for cryptocurrencies. Prices for Bitcoin, Ethereum and Litecoin are predicted using the traditional forecasting model for timeseries ARIMA, the Prophet Model and deep learning algorithm LSTM. The results of the three models were evaluated and the LSTM Model was found to outperform the Prophet as well as the ARIMA model.

Vikram Kanth, Ashley McaAbee, Murali Tummala, John McEachen

As the threat of cyber attack grows ever larger, new approaches to security are required. While there are several different types of intrusion detection systems (IDS), collaborative IDS (CIDS) offers particular promise in identifying distributed, coordinated attacks that might otherwise elude detection. Even for CIDS, there are unresolved issues associated with trusting participants and aggregating data. Blockchain technology appears capable of addressing those issues if practical implementation strategies can be developed. To that end, we implement an Ethereum blockchain-based CIDS leveraging pluggable authentication modules. Our system is specifically crafted to detect doorknob rattling attacks by immutably recording login activity in a blockchain-protected ledger.

Abhay Goel, Abhishek Sharma, Deepak Gupta, Ashish Khanna

No abstract is available for this record.