Since the introduction of Bitcoin, numerous studies on Bitcoin mining attacks have been conducted, and as a result, many countermeasures to these attacks have been proposed. The reputation-based mining paradigm is a comprehensive countermeasure solution to this problem with the goal of regulating the mining process and preventing mining attacks. This is accomplished by incentivizing miners to avoid dishonest mining strategies using reward and punishment mechanisms. This model was validated solely based on game theoretical analyses and the real-world implications of this model are not known due to the lack of empirical data. To shed light on this issue, we designed a simulated mining platform to examine the effectiveness of the reputation-based mining paradigm through data analysis. We implemented block withholding attacks in our simulation and ran the following three scenarios: Reputation mode, non-reputation mode, and no attack mode. By comparing the results from these three scenarios, interestingly we found that the reputation-based mining paradigm decreases the number of block withholding attacks, and as a result, the actual revenue of individual miners becomes closer to their theoretical expected revenue. In addition, we observed that the confidence interval test can effectively detect block withholding attacks however, the test also results in a small number of false positive cases. Since the effectiveness of the reputation-based model relies on attack detection, further research is needed to investigate the effect of this model on other dishonest mining strategies. / Includes bibliography. / Thesis (MS)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

The Blockchain concept was originally developed to provide security in the Bitcoin cryptocurrency network, where trust is achieved through the provision of an agreed-upon and immutable record of transactions between parties. The use of a Blockchain as a secure, publicly distributed ledger is applicable to fields beyond finance, and is an emerging area of research across many other fields in the industry. This thesis considers the feasibility of using a Blockchain to facilitate secured information sharing between parties, where a lack of trust and absence of central control are common characteristics. Implementation of a Blockchain Information Sharing system will be designed on an existing Blockchain network with as a communicative party members sharing secured information. The benefits and risks associated with using a public Blockchain for information sharing will also be discussed. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

A review of digital forensics today shows that it could be exposed to threats jeopardizing the digital evidence integrity. There are several techniques to countermeasure this risk, one of which is the method that involves the use of blockchains. Blockchains use an advanced system to keep the data within it persistent and transparent, which makes it a natural candidate for everything integrity-sensitive. Several blockchain techniques and infrastructures have been described in this study, based on previous studies and other literature work. Interviews and experiments made a comparison between traditional digital forensic methodologies versus blockchains possible in later chapters. The results showed that blockchains could be the answer to securing digital evidence integrity. However, there is still a lot more work to be done before blockchains are ready to be implemented in production systems. The results of the blockchain analysis are presented such that they can be used as an aid to further research, either theoretically or practically, digital evidence blockchains.

Blockchains, like many “disruptive” digital media, continue to garner significant academic and popular attention about what they are. Recent critical provocations in geography and cognate disciplines shift lines of enquiry to interrogate the material realities of digital technologies, emphasizing instead how they are lived. Inspired by critical and feminist thinking, the primary task of this dissertation is to follow the latter mode of analysis and present a critical cartography of blockchains, loosely defined. The critical cartography presented in this study sketches a conceptual and methodological map of context-specific and intimate blockchains practices I participated in and experienced from 2013-2020, in a mostly Canadian context. I construct this cartography by using a variety of autobiographical and auto-ethnographic methods that are sometimes buttressed by more conventional qualitative methods. Research reveals that blockchains have the capacity to become economic in a diversity of ways, enacting multiple rowdy characteristics of capitalism, a phenomenon I term rambunctious capitalism. Rambunctious economic flows actualizing through blockchains rely on different situations of power to enact nomadic subject/ivities in a variety of spatial, temporal, and material contexts. Specifically, the blockchain practices addressed in this dissertation highlight the embodiment of joyful moments for a pregnant body working in Toronto’s crypto-economy, the algorhythmic impacts of blockchain hard fork events, where code participates in the instantiation of diverse temporalities that produce uneven geographies, and the materialization of Canadian policy discourses about blockchains that position and, in some cases, implement these media as smart solutions to civic service delivery. Findings presented throughout this study contribute to feminist and digital geographies by offering autobiographical, auto-ethnographic, and intimate accounts of blockchains, and how they are practiced as lived and multiple realities. In addition, this dissertation also adds ethnographic research to the now expansive multi-disciplinary scholarship on blockchains and cryptocurrencies to understand how these media operate in specific contexts. / Graduate

A research article submitted to the Faculty of Commerce, Law and Management, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Business Administration Johannesburg, 2018 / Blockchain technology is a foundational technology with various use cases that can significantly impact the manner in which banking is carried out in South Africa. The following paper seeks to put together a framework for understanding the potential effect of blockchain technology on the South African banking environment, with a specific focus on how blockchain technology will impact the South African banking environment (i.e. the applications and use cases) and when this impact will take place. A qualitative approach to addressing the problem statement was adopted, specifically in the form of focus interviews and strategic discussions with subject matter experts in both the blockchain and South African banking environment. Findings indicate that there are number of blockchain applications that can impact the South African banking environment namely, Private Digital Ledgers, Smart Contracts and Tokens/ Cryptocurrencies. Further to this, research indicates that the former is most likely in the short term, while the latter two applications are subject to a high-level stakeholder coordination, a high level of effort in educating the end customer and a high level of friction from existing systems and process, and will therefore only realise mass adoption in the long-term. As a result, this research contributes to providing an initial view of which applications are most likely to be adopted by South African banks and can form the foundation for further research in this area. / E.K. 2019

The amount of connected Internet of Things devices has seen a large growth during the last couple of years and shows no signs of slowing down. Considering the momentum of the technological advancement in our society with new technologies such as blockchains, AI and machine learning, a large amount of issues could occur if not prevented beforehand, especially within security. Therefore this thesis will examine how to maintain the information security in an Internet of Things network based on blockchains and user participation, by taking an exploratory approach to create an understanding of the issues and possible solutions when implementing a network of this type. By using a case developed together with Luleå Kommun this thesis takes a qualitative approach to the research. This is done by using solutions to issues which appeared during the development of this implementation to draw a conclusion on how to maintain the information security in an Internet of Things network based on blockchains and user participation.

With the invention of the cryptocurrency Bitcoin in 2009, the world's first blockchain application was developed. While academic research gradually investigates blockchain more closely and attempts to understand its functioning in the financial sector, the technology is rapidly evolving, and eco-systems grow exponentially. Blockchains are now seen as an emerging field of digitization, possessing challenges to achieving sustainability. The research is still scattered and has not presented a common guideline for understanding what features of blockchains enable the development of financial trading markets sustainably. Therefore, the question remains: how do blockchains facilitate the development of sustainable financial trading markets and services? A qualitative and iterative study was conducted to summarize the priori concepts available in the literature into a conceptual framework consisting of four themes of sustainability and eleven categories of affordances to answer this question. Semi-structured interviews were conducted to understand what features of blockchains facilitate achieving these eleven categories of affordances and to test and modify the conceptual framework. The findings from the interviews confirmed seven categories summarized from literature to be creditable, while the rest of the affordances were left with a neutral view. Importantly, the findings reveal that these categories are highly interconnected, creating tensions between different themes of sustainability.

Blockchain has become the most revolutionary technology in the 21st century. In recent years, one of the concerns of world energy isn't just sustainability yet, in addition, being secure and reliable also. Since information and energy security are the main concern for the present and future services, this thesis is focused on the challenge of how to trade energy securely on the background of using distributed marketplaces that can be applied. The core technology used in this thesis is distributed ledger, specifically blockchain. Since this technology has recently gained much attention because of its functionalities such as transparency, immutability, irreversibility, security, etc, we tried to convey a solution for the implementation of a secure peer-to-peer (P2P) energy trading network over a suitable blockchain platform. Furthermore, blockchain enables traceability of the origin of data which is called data provenience. In this work, we applied a secure blockchain technology in peer-to-peer energy sharing or trading system where the prosumer and consumer can trade their energies through a secure channel or network. Furthermore, the service management functionalities such as security, reliability, flexibility, and scalability are achieved through the implementation. \\ This thesis is focused on the current proposals for p2p energy trading using blockchain and how to select a suitable blockchain technique to implement such a p2p energy trading network. In addition, we provide an implementation of such a secure network under blockchain and proper management functions. The choices of the system models, blockchain technology, and the consensus algorithm are based on literature review, and it carried to an experimental implementation where the feasibility of that system model has been validated through the output results.

We aim to identify factors that are critical in determining whether or not blockchain adoption arises in various market structures, and give guidance for addressing the challenges of blockchain implementation. In Chapter 2, we construct an economic framework for understanding the incentives of the firms in a supply chain to form a blockchain consortium. We find that blockchain reduces information asymmetry for consumers, thereby enhancing consumer welfare. Consumer welfare gains can be sufficiently large that blockchain adoption is socially beneficial; nonetheless, we find that blockchain adoption does not arise in equilibrium. This situation arises because blockchain adoption costs are borne by manufacturers, and manufacturers cannot extract consumer gains through prices due to the competitive nature of the manufacturing sector. We offer a system of transfers to generate blockchain adoption in equilibrium when it is socially beneficial. In Chapter 3, we investigate a variation of the model described in Chapter 2. Our analysis incorporates the blockchain’s ability to trace shipments and generate cost savings for the manufacturers who join the blockchain. Although the blockchain enables early recalls of defective goods with higher probability, and thus, reduces expected unit costs for all the manufacturers on the blockchain, such gains are still competed away and blockchain adoption does not arise in equilibrium. This result strengthens our earlier findings on the incentive misalignment in a perfectly competitive setting. The associated welfare implications of this model are similar to those in Chapter 2. In Chapter 4, we study a setting in which the consumer prices are determined exogenously. With this setting of sticky price, there exists a certain level of competition but it is not perfect. As a result, the manufacturer gains from blockchain adoption may be strictly positive, in contrast to two results in Chapters 2 and 3 where the gains are always competed away. We find that blockchain unequivocally benefits consumers but has an ambiguous effect upon the welfare of manufacturers. There exist conditions under which, although the blockchain improves global welfare, blockchain adoption does not arise in equilibrium. We refer to such a scenario as an adoption failure, and again a system of transfers is proposed to resolve that failure. In Chapter 5, we examine whether blockchain adoption arises in equilibrium for a supply chain in which a single risk-averse manufacturer sells directly to consumers; thus, the manufacturer possesses market power. In this setting, we find that blockchain adoption always enhances manufacturer welfare when the adoption cost is zero. While two results in Chapters 2 and 3 demonstrate that blockchain adoption does not arise when the manufacturing sector is perfectly competitive, our findings clarify that the failure of blockchain adoption is not generic across all market structures. Rather, blockchain adoption arises in equilibrium for supply chains when the manufacturer possesses market power and when the adoption cost is sufficiently small.

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