The rapid advancement in encryption and network computing gave birth to new tools and products that have influenced the local and global economy alike. One recent and notable example is the emergence of virtual currencies, also known as cryptocurrencies or digital currencies. Virtual currencies, such as Bitcoin, introduced a fundamental transformation that affected the way goods, services, and assets are exchanged. As a result of its distributed ledgers based on blockchain, cryptocurrencies not only offer some unique advantages to the economy, investors, and consumers, but also pose considerable risks to users and challenges for regulators when fitting the new technology into the old legal framework. This paper attempts to model the volatility of bitcoin using 5 variants of the GARCH model namely: GARCH(1,1), EGARCH(1,1) IGARCH(1,1) TGARCH(1,1) and GJR-GARCH(1,1). Once the best model is selected, an OLS regression was ran on the volatility series to measure the day of the week the effect. The results indicate that the TGARCH (1,1) model best fits the volatility price for the data. Moreover, Sunday appears as the most significant day in the week. A nontechnical discussion of several aspects and features of virtual currencies and a glimpse at what the future may hold for these decentralized currencies is also presented.

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 10.0px Helvetica} Blockchain is a distributed ledger technology enabling digital transactions without the need for central governance. Once transactions are added to the blockchain, they cannot be altered. One of the main challenges of blockchain implementation is how to create a scalable network meaning verifying many transactions per second. The goal of this thesis is to survey different approaches for scaling blockchain technologies. Scalability is one of the main drivers in blockchain development, and an important factor when understanding the future progress of blockchain. The energy sector is in need of further digitalisation and blockchain is therefore of interest to enhance the digital development of smart grids and Internet of Things. The focus of this work is put on a case study in the energy sector regarding a payment system for electrified roads. To research those questions a qualitative method based on interviews with blockchain experts and actors in electrified roads projects was applied. The interviews were processed and summarised, and thereafter related to map current developments and needs in the blockchain technology. This thesis points to the importance of considering the trilemma, stating that blockchain can be two of three things; scalable, decentralised, secure. Further, Greenspan’s criteria are applied in order to recognise the value of blockchain. These criteria together with the trilemma and understanding blockchain’s placement in the hype cycle, are of value when implementing blockchain. The study shows that blockchain technology is at an early stage and questions remain regarding future business use. Scalability solutions are both technical and case specific and it is found that future solutions for scaling blockchain are emerging.

Proyecto de Actividad formativa equivalente a tesis (AFET) / Programa de magíster en derecho tributario / El objetivo del presente trabajo es determinar el régimen tributario aplicable a las criptomonedas. Para ello, se analizará la normativa administrativa y legislación comparada en la materia, como también la legislación nacional civil vigente. Como resultado, determinaremos la naturaleza jurídica de las criptomonedas y las consecuencias tributarias que de ello derivan. / The purpose of this work is to determine the cryptocurrencies’ applicable tax regime. For this purpose, we will analyze the relevant legal and administrative regulation, as well as the Chilean civil legislation. As a result, we will determine the legal nature of cryptocurrencies and the proper tax treatment derived from it.

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Data ownership is of fundamental importance in the digital economy of today. Commercializing academic research, whilst maintaining ownership of it, is a task that can now be accomplished due to the strengths of blockchain technology, which allows data to be registered, made unique, and traced to its origins. We propose a blockchain use-case for licencing academic research, based off an academic project named UniCoin. In this thesis, we discuss how to fairly attribute credit between all sources of knowledge that contribute to new pieces of academic research, using citation network analysis and centrality measures. Katz centrality, in-degree centrality, and PageRank are three potentially useful centrality measures, with varying results: these are compared using case studies based on three papers co-authored by Andrei Shleifer. We use these centrality measures to guide how to fairly attribute credit, and thus how to distribute licencing revenues generated through UniCoin.

Food is vital to human life. Therefore, ensuring its safety as it moves from producer to consumer in food supply chains (FSCs) is essential. This can be achieved through the use of food traceability technology which enables track and trace of produce within a FSC. Recently, blockchain technology (BCT) has shown great potential to enhance traceability in FSCs, owing to its ability to securely store data in a decentralised and tamper-evident manner. However, it appears that research on blockchain-enabled food traceability exists primarily within the context of large FSCs, whilst scarce for local FSCs in which traceability is often an inefficient and manual process. Given this background, this exploratory research is carried out, to investigate whether a blockchain-enabled system can be used to improve traceability in local FSCs. To do this, we (i) collaborate with Oranjezicht City Farm Market (OZCFM) - a farmers market in Cape Town, the smallholder farmers that supply OZCFM with fresh local produce and the OZCFM patrons that purchase the produce; (ii) map out the local FSC by conducting observations and running surveys with the aforementioned actors; (iii) design, develop and pilot FoodPrint - a web based and blockchain-enabled food traceability application. During the pilot within the OZCFM-related local FSC, FoodPrint is used to capture data on the harvest, transportation and storage of produce; and reveal produce provenance at destination by scanning of supplier-produce specific quick response (QR) codes. We find that FoodPrint provides tamper-evident traceability and authentic transparency of produce related data to the local FSC actors. Further, we note that scanning a FoodPrint QR code for produce provenance does not enhance the consumers trust of the local FSC, as it pre-exists. This implies that local FSCs with existing and functional trust mechanisms do not benefit from trust-enhancing mechanisms such as blockchain-enabled traceability. Future work may consider data privacy in FSCs and automating FSC data entry to reduce the risk of fraud.

<div>This dissertation consists of three essays that study problems that decision-makers face when hitherto niche technologies scale up. Typically, scaling up involves market expansion with participation from a variety of agents with complex preferences, using the technology to maximize their utility. A major problem for the decision maker then is either one or a combination of the following: deciding policy for optimal business or social outcomes, implementing effcient demand allocation mechanisms or improving market design.</div>

This thesis examines methods which could be used for developing MMORPG games so that there is no single entity that could arbitrarily control game mechanics, virtual assets or other game aspects. The theoretical part systematically analyzes the usual aspects of MMORPG games, then the principles of decentralized cryptocurrencies are presented, and one of them, Ethereum, is analyzed in more detail. Based on this theoretical knowledge, methods are proposed on how to use Ethereum to implement the identified aspects of MMORPG games, and the restrictions which must be imposed on these aspects are recognized. The practical part then introduces a specific implementation of MMORPG game on Ethereum, which demonstrates the above methods. In conclusion, the chosen approach is compared to the games with a common client-server architecture, especially in terms of complexity and gaming costs. 1

The thesis deals with the creation of the application solution for device localization using blockchain.The first part of the thesis is an overview of blockchain platforms and existing projects working with localization and description of technologies used in the implementation. The second part deals with the creation of the solution which is divided into the mobile application, the server application and the blockchain part. The last part describes testing, results, evaluation of the whole solution and its use.

Blockchain is a technology that allows the decentralization of data stored in a way that there is no single central actor to control or modify the data. Bitcoin is the first successful blockchain application implemented with the concept known as cryptocurrency that allows a transaction flow without any bank or government to control it. Blockchain is associated with benefits including high level of transparency, integrity, trust and confidence for the participants. Blockchain is still at early stage but it is a promising technology that has the potential to impact many more areas in the future. However, its security area is still the weakest part of it which still needs improvement. Therefore, this thesis aims to make a review of the blockchain security issues using the past published literature between 2010 and 2021. This thesis conducts a review on 20 articles to provide a scientific input that gives an overall view of existing security threats and their respective impacts on blockchain system. This thesis starts with an overview of how blockchain system works and briefly discuss on the information security of blockchain. The collection of security attacks from the literature has been carried out by using concept centric matrix approach. This process resulted to security attacks that were classified based on four layers of blockchain system architecture. Then, the security attacks are mapped to common security impacts including double spending, unauthorized code execution, denial of service, unfair income and privacy key leakage. These security impacts were analyzed which led to the conclusion that the major security issues on blockchain result from its P2P network architecture and its consensus mechanism. Besides, some possible solutions to mitigate the security threats were discussed though, more effort in developing new security measures and protocol framework is still required.