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.

This study discusses the acceptance level of cryptocurrency in countries of the world. Study takes a deep dive on what does affect the acceptance level of cryptocurrency and what should be expected if same changes would to happen in countries income level, technological level, financial level, and education level. The study gives an overview of current up to date situation of cryptocurrency. In this research we have conducted a cross-sectional data analysis of cryptocurrency acceptance level for year 2021. Study is focused on both decentralized and centralized acceptance level thus why the research has treated both transactions volume on exchanges and Defi. The study found that countries with higher income could have higher acceptance level of cryptocurrency, but the effect is not that immense. Other factors such as education, financial access and internet access had an inconclusive effect on the acceptance level. The study also shows that there is no prove of that pervious qualitative research result upholds or have any systematic relation with quantitative research results.

No description available.

This thesis is one in a group of several theses that are researching different subjects in the development of a new cryptocurrency. For a few years now, the cryptocurrency market has grown dramatically, in the lead of the original cryptocurrency Bitcoin. Today, most cryptocurrencies' validation-technology, including Bitcoin's, are based on Proof-of-Work (PoW), i.e., a system where transaction validation is made by servers calculating mathematical problems. PoW results in high energy consumption and slow transaction speed. In this cryptocurrency, the validation mechanism will build on a technology called Proof-of-Stake (PoS). PoS does not yield as high energy consumption and often leads to faster transaction speed. The specific technique for validation in this system is that validators bet their coins to validate transactions and get rewards in the form of transaction fees if they end up conforming the transactions that reach consensus among the validators. In particular, the purpose of this report is to research the risk and reward for validators in the betting process and from this develop a reward policy which yields a fast and secure validation. The methods used for solving the problems are simulations based on Monte Carlo methods. From the simulations, the results are discussed and compared. Also, this report will cover economic theories behind cryptocurrencies, mainly focusing on monetary policy and the transaction markets. The findings of this report are several risk functions for different topologies and winning conditions considered during the development of the cryptocurrency. Further, a conclusion was that the expected value of profit for validators need to be constant, independent of when the bets are made with regard to previous bets. From this, a reward function which distributes rewards between winning validators was formed. Another, economical conclusion from this was that, in the long run, the expected value of profit of betting should converge to zero due to a perfect competition market. / Denna kandidatuppsats är en av era uppsatser som analyserar olika områden i utvecklingen av en ny kryptovaluta. Under de senaste åren har kryptovalutamarknaden vuxit dramatiskt, där Bitcoin har varit ledande. Idag bygger de flesta kryptovalutors valideringsteknik, inklusive Bitcoins, på Proof-of-Work (PoW), d.v.s. ett system där transaktionsvalideringen görs av servrar som beräknar komplicerade matematiska problem. Detta resulterar i en hög energiförbrukning och i många fall långsamma transaktionshastigheter. I denna kryptovaluta kommer valideringsmekanismen baseras på en teknik som kallas Proof-of-Stake (PoS) vilket leder till en substantiellt lägre energiförbrukning och högre transaktionshastigheter. Tekniken för valideringen i det här systemet är baserat på att validerare i systemet satsar sina egna mynt för att validera transaktioner och får belöningar i form av transaktionsavgifter om de validerar den transaktion som når konsensus i blockkedjan. I synnerhet är syftet med rapporten att formulera riskerna och de möjliga belöningarna för validerare i bettingprocessen och därmed hitta ett belöningssystem som leder till en snabb och säker kryptovaluta när det gäller validering. De metoder som används för att lösa problemen är simuleringar baserade på Monte Carlo metoder. Slutresultatet av denna rapport är era riskfunktioner för olika topologier och villkor för de vinnande validerarna, beräkningar för väntevärde och belöningsfunktioner för validering. Vidare har slutsatsen dragits att väntevärdet av att göra ett bet måste vara konstant med avseende på när bettet görs. Från detta togs en belöningsfunktion fram som fördelar belöningar mellan vinnande validerare. En annan, ekonomisk slutsats, var att i det långa loppet kommer väntevärdet av vinsten för att betta konvergera till noll på grund av att en perfekt konkurrensmarknad antas.

Many applications and protocols on blockchain platforms are reliant on real-world data which exists outside the blockchain, something which is not directly accessible through these platforms. To bridge this gap, blockchain oracles help these applications and protocols by providing them with this data. As different data used by these applications and protocols can result in different outcomes occurring, one way for attackers to attack these applications and protocols is to attack the oracles they rely on. This thesis investigates what types of fundamental attacks are possible on oracles hosted on Ethereum, potential ways to protect against them and how these attacks can be categorized. It also investigates if the different attributes of Solana or Corda provides any protection against these attacks in some way. In order to answer these questions, the different blockchain platforms are researched and investigated, along with different oracles and attacks on oracles. A framework which describes the different states data in a oracle can be in was also created in order to help find attacks. In total, eleven different fundamental attacks on Ethereum oracles were found along with different methods to protect against them. A majority of these attacks were deemed to be able to be done in full capability by both independent and nation-state attackers. Both Solana and Corda were found to provide some inherent protection against some of these attacks. Solana was found to be able to almost fully eliminate one type of attack due to its execution environment. Corda was found to make many of the found attacks harder to execute for an attacker, mainly due to its lack of anonymity. / Många applikationer och protokoll på blockkedje-plattformar är beroende av verklig data som existerar utanför blockkedjan, något som inte är direkt nåbart genom dessa plattformar. I syfte att göra denna data nåbar, så hjälper orakel på blockkedjor dessa applikationer och protokoll genom att tillhandahålla dem denna data. Eftersom dessa applikationer och protokoll kan ha olika utfall beroende på vilken data de använder sig av, så är en metod att attackera dem genom att attackera dem orakel som de använder sig av. Denna avhandling undersöker vilka typer av fundamentala attacker som är möjliga mot orakel som körs på Ethereum, potentiella sätt att skydda mot attackerna samt hur dessa attacker kan kategoriseras. Den undersöker även ifall de olika attributen som finns hos Solana eller Corda ger något skydd mot dessa attacker på något sätt. För att besvara dessa frågor har de olika blockkedjeplattformarna undersökts. Även olika orakel samt attacker mot orakel har undersökts. Ett ramverk som beskriver de olika tillstånden som data i ett orakel kan befinna sig i skapades med syfte att underlätta hittandet av attacker. Totalt så hittades elva olika fundamentala attacker mot orakel som körs på Ethereum tillsammans med tillhörande skyddsmetoder. Majoriteten av dessa attacker bedömdes kunna genomföras i full förmåga av både självständiga angripare samt nationssponsrade angripare. Både Solana och Corda visade sig ge skydd mot vissa av de elva attackerna genom sina attribut. Solana kan genom sin exekveringsmiljö nästan helt eliminera möjligheten av en av attackerna. Corda visade sig göra flera av de olika attackerna svårare att genomföra för angripare, främst på grund av sin avsaknad av anonymitet i plattformen.

The main purpose of a vehicle information system using blockchain is to create a transparent and reliable information system which will help consumers buy a vehicle; it is a vehicle information system. The blockchain system will create a time sequence chain of events database for each vehicle from the original sale. It will include insurance, vehicle repair, and vehicle resale. This project is mainly divided into three parts. Part one is used by the administration who will create the blockchain and will give authentication to a different organization to create the blockchain. Part two will be used by the Organization to create a block in the blockchain. Part three will be used by customers who want to get information about the vehicle.

Blockchain technologies have gradually gained popularity since the beginning of 2010. As of 2018, many companies and financial institutions are redesigning and building new sys-tems with blockchain technologies as major foundation. On paper, the blockchain has nu-merous advantages over the traditional centralized approach, however, this study showed, that there are some large drawbacks, which are associated with usage of blockchain. Themost significant downsides are blockchain’s low performance, enormous cost and highenvironmental impact, compared to traditional client-server based systems. Therefore, the overall goal of this study was to highlight the importance of consider-ing these drawbacks and discuss, how performing of a detailed feature analysis during the design phase, might guide application developers to the correct path, during theimplementation phase of a system, when blockchain is considered being an alternativeto the traditional client-server approach. As the result of this study, it turned out, thatboth client-server and blockchain based approaches do have their respective use casesand disadvantages. A conclusion was drawn, that the best approach would be eitherto use a mix of both technologies, or to use the blockchain as a verification mechanismbehind a client-server backend, in order to improve its data integrity and persistencequality attributes.

With the explosion of Bitcoin, various cryptocurrencies are beginning to garner incredible amounts of attention from speculators and institutional investors alike. Simultaneously, the rise in the number of occurrences of cyber ransom attacks has proven to be an increasingly relevant part of the conversation in the formative years of the Bitcoin ecosystem, as hackers demand payments be in the form of bitcoin. To test the relative impact of these different ransom events on the price of bitcoin, this paper conducts an event study to quantify the reaction by investors upon revelation of the news. In addition, it examines differences between Bitcoin and two other cryptocurrencies, Ethereum and Litecoin, to control for any liquidity effects of victims buying up large sums of bitcoin. The findings of the study indicate that following the ransom events there is a positive price reaction, supporting the claim that investors in Bitcoin generally perceive these events as good news. This could have a profound effect on the development and further adoption of cryptocurrencies, as regulators try to determine whether or not to intervene.

In this paper, we analyse the relation between financial system and financial crises. Our goal is to find how, on the one hand, changes in the financial system affect the prospects for financial crises and, on the other hand, how the occurrence of financial crises shape the core elements of the financial system. We start by defining the financial crisis from three different perspectives. After it, we present the comprehensive history of financial crises that will allow us to continue by drawing some common patterns that are universal. Universal patterns in crises give us the ground for contemplating on some universal policy responses where we again follow different approaches. Taking into account the specifics of modern times and using the young and promising economy based on the blockchain, we are asking the question is this time different?. Analysis of initial development steps in the digital, trustless world gives us the basis for drawing parallels with the reality and the history. Our results suggest that there are many similarities throughout history and between the real and digital world. Instead of providing an exact answer on the question is this time different we conclude that there is a present strong feeling of Deja vu.