This thesis proposes an implementation for a decentralized version of the Git version controlsystem. This is achieved using a simple distributed DAG ledger. The thesis analyzeshow the decentralization of Git affects security. Use and misuse cases are used to compareand evaluate conventional Git web services and a decentralized version of Git. Theproposed method for managing the state of the Git project is described as a voting systemwhere participants in a Git project vote on changes to be made. The security evaluationfound that the removal of privileged roles in the Git version control system, mitigated thepossibility of malicious maintainers taking over the project. However, with the introductionof the DAG ledger and the decentralization, the possibility of a malicious actor takingover the network using Sybil attack arises, which in turn could cause the same issues as amalicious maintainer.

The original FlexiChain and its descendants are a revolutionary distributed ledger technology (DLT) for cyber-physical systems (CPS) and their embedded systems (ES). FlexiChain, a DLT implementation, uses cryptography, distributed ledgers, peer-to-peer communications, scalable networks, and consensus. FlexiChain facilitates data structure agreements. This thesis offers a Block Directed Acyclic Graph (BDAG) architecture to link blocks to their forerunners to speed up validation. These data blocks are securely linked. This dissertation introduces Proof of Rapid Authentication, a novel consensus algorithm. This innovative method uses a distributed file to safely store a unique identifier (UID) based on node attributes to verify two blocks faster. This study also addresses CPS hardware security. A system of interconnected, user-unique identifiers allows each block's history to be monitored. This maintains each transaction and the validators who checked the block to ensure trustworthiness and honesty. We constructed a digital version that stays in sync with the distributed ledger as all nodes are linked by a NodeChain. The ledger is distributed without compromising node autonomy. Moreover, FlexiChain Layer 0 distributed ledger is also introduced and can connect and validate Layer 1 blockchains. This project produced a DAG-based blockchain integration platform with hardware security. The results illustrate a practical technique for creating a system depending on diverse applications' needs. This research's design and execution showed faster authentication, less cost, less complexity, greater scalability, higher interoperability, and reduced power consumption.

Organizations in the financial services industry are coming under increasing pressure. Regulatory compliance, operational inefficiencies, and the higher cost of capital are all forcing incumbents to adapt. As such, there are strong incentives for technological innovations that either reduce costs or generate new revenue. Distributed ledger technology (DLT), the foundation of bitcoin, is one of the latest innovations that appear to be the source of an imminent solution. An identified area with great potential for DLT is the post-trade market where market players, such as central securities depositories (CSDs), are heavily investing in pilot studies of how DLT may affect their business activities. In fact, the practical potential of adoption has been demonstrated by experiments and proof of concepts. However, while technological and regulatory aspects have been more frequently discussed in academia, the business dimension of the adoption of DLT within CSDs has received less attention. In this thesis, the business opportunities and challenges of the adoption of DLT within CSDs were explored, coupled with an analysis of the contextual factors affecting the rate of adoption. Further, this thesis compares the throughput performance between a centralized system and a private permissioned network. By performing a multiple-case study with a mixed-methodology approach, the researcher analyzed the literature, conducted a performance evaluation, and interviewed several industry experts. The conclusions suggest that the main business opportunities are the incorporation of digital assets and CSDs potential role as the gatekeeper of private networks. The main identified challenges related to adoption were interoperability, standardization, collaboration, scalability, defining applicable use cases, and governance and regulatory frameworks. Further, the performance evaluation suggests that the throughput performance of the centralized system outperforms the private permissioned network by an average of 6.5 times. The findings have both practical and academic implications. In academics, this thesis lays the foundation for further studies and provides new insights into the business dimensions of the adoption of DLT within CSDs. For practitioners, this thesis provides a basis for discussion and assessment of the entailed challenges related to the adoption of DLT within the post-trade market. / Organisationer inom finansbranschen utsätts för ökande press. Regelverksefterlevnad, operationell ineffektivitet och den högre kapitalkostnaden tvingar aktörer att anpassa sig. Som sådan finns det starka incitament för tekniska innovationer som antingen minskar kostnaderna eller genererar nya intäkter. Distribuerade liggare (DLT), grunden för bitcoin, är en av de senaste innovationerna som visar stor potential. Ett identifierat område med stor potential för DLT är post-trade-marknaden där marknadsaktörer, såsom centrala värdepappersförvarare (CSD), har investerat i pilotstudier av hur DLT kan påverka deras affärsverksamhet. Faktum är att den praktiska potentialen har demonstrerats genom experiment och bevis på koncept. Men även om tekniska och regulatoriska aspekter har diskuterats mer frekvent i den akademiska världen, har affärsdimensionen med införandet av DLT inom CSD:er fått mindre uppmärksamhet. I det här examensarbetet utforskades affärsmöjligheterna och utmaningarna med införandet av DLT inom CSDs, tillsammans med en analys av de marknadsmässiga faktorerna som påverkar spridningen av teknologin. Vidare jämför denna avhandling genomströmningsprestandan mellan ett centraliserat system och ett private permissioned nätverk. Genom att utföra en flerfallsstudie med en blandad metodologi analyserade forskaren litteraturen, genomförde en prestandautvärdering och intervjuade flera branschexperter. Slutsatserna tyder på att de huvudsakliga affärsmöjligheterna är integreringen av digitala tillgångar och CSD:s potentiella roll som gatekeeper för privata nätverk. De främsta identifierade utmaningarna i samband med införandet av DLT var interoperabilitet, standardisering, samarbete, skalbarhet, definition av tillämpliga användningsfall samt styrning och regelverk. Vidare antyder prestandautvärderingen att genomströmningsprestandan för det centraliserade systemet överträffar det private permissioned nätverket med i genomsnitt 6,5 gånger. Resultaten har både praktiska och akademiska implikationer. Inom akademin lägger denna avhandling grunden för fortsatta studier och ger nya insikter om affärsdimensionerna av införandet av DLT inom CSDs. För praktiker ger detta examensarbete ett underlag för diskussion och bedömning av de medförda utmaningarna relaterade till införandet av DLT inom post-trade-marknaden.

When the Internet was created it did not include any protocol for identifying the person behind the computer. Instead, the act of identification has primarily been established by trusting a third party. But, the rise of Distributed Ledger Technology has made it possible to authenticate a digital identity and build trust without the need of a third party. The Swedish Maritime Administration are currently validating a new maritime digital infrastructure for the maritime transportation industry. The goal is to reduce the number of accidents, fuel consumption and voyage costs. Involved actors has their identity stored in a central registry that relies on the trust of a third party. This thesis investigates how a conversion from the centralized identity registry to a decentralized identity registry affects the usability and the risk for compromised data integrity. This is done by implementing a Proof of Concept of a decentralized identity registry that replaces the current centralized registry, and comparing them. The decentralized Proof of Concept’s risk for compromised data integrity is 95.1% less compared with the centralized registry, but this comes with a loss of 53% in efficiency.

This thesis aims to explore the compliance of blockchain technology and the GDPR. The GDPR was implemented for the EU member states in May 2018 with the purpose of harmonizing data protection regulation. However, the regulation is based on the notion that data is stored and processed in a centralized system. This causes an issue when it comes to distributed networks, and in particular with the distributed ledger technology (DLT), the underlying technology of blockchain. For this thesis, a literature review has been conducted to investigate the problems of GDPR compliance for blockchain projects, and what technical solutions exist to make a blockchain solution more GDPR compliant. In addition, interviews have been conducted to investigate the technical and legal perspectives on the current and future situations of regulation and technology. Compatibility problems mainly concern the immutability and transparency of a blockchain and examples of technical solutions that handle those problems can be found in the literature. Nevertheless, none of the discussed solutions are yet to guarantee full GDPR compliance. The technical and legal perspectives share ideas of the main compliance issues. However, differences such as interpretation of technical details can be identified, indicating problems to arise when regulating blockchains in the future. Further interdisciplinary work on guidelines for the GDPR is necessary for blockchain projects to be successful in complying with the regulation as well as to strengthen the technology neutrality of the GDPR.

The issue of food traceability is one that affects a great number of sectors and policy areas. Within the EU, there is increasing demand from consumers, businesses and institutions to have more direct access to information about how food is produced, transformed, and distributed. Currently, however, practices in the industry are very much open to human error. Databases are highly vulnerable to inaccuracies and hacking, as well as deliberate faults caused by corruption or fraudulent conduct. With food traceability being so closely related to trade and public health issues, there is arguably increasing incentive for the EU to seek alternative tools to increase transparency and accountability throughout supply chains. Consequently, this paper will examine a possible alternative to current practices by evaluating the applicability of 'blockchain' technology, namely a system of digitised, decentralised ledgers, which could allow key stakeholders to access information about the provenance of food immediately, comprehensively and securely. The analysis will focus specifically on Extra Virgin Olive Oil (EVOO), one of the most adulterated products in the food industry, identifying gaps and opportunities in current traceability systems. The research question tackled in this paper, therefore, may be formulated as follows: how and to what extent could blockchain technology constitute a sustainable solution for improving the traceability of EVOO within the EU? The paper begins with a brief overview of the issue and an explanation of the research methodology used, followed by an elaboration of key terms and concepts and a detailed explanation of the principles underlying blockchain technology. Subsequently, the key challenges and opportunities associated with blockchain-based traceability systems are examined through a case study, followed by an analysis aimed at assessing the sustainability of blockchain solutions for the EVOO sector. The conclusion, lastly, provides an overview of relevant findings and proposes a final assessment.

Creating standardized infrastructures for new technologies has become a frequent event in recent years, forcing competing firms to together collaborate in order to develop and mutually agree on a common standard. This is due to technologies such as blockchain (distributed ledger) technology that need interoperability to reach its full potential, making the collaboration aspect crucial for organizations that want to adapt to the technology. Therefore, this study’s purpose is to identify and analyze the challenges of creating such a standardized infrastructure. A case study was used to analyze these challenges, which involved experts of blockchain technology and three Nordic banks connected to the blockchain consortium R3. First, a pre-study took place with the help of blockchain experts, who helped identify potential problems regarding blockchain (distributed ledger) technology. Secondly, a main study was conducted consisting of four interviews with key persons representing the banks, in addition to collecting secondary data via news articles, and press releases. With the help of co-opetition theory and a technical description of blockchain (distributed ledger) technology, an analytical model was developed to support the analysis of the data collection. The analysis focus on aspects of co-opetition drivers, co-opetition capabilities, co-opetition dynamics and blockchain aspects, which were used to showcase the challenges of collaborating on creating a standardized infrastructure. The result of this study highlights the importance of learning and educational aspects, the size of a cooperation and threats from other competing solutions, which generates challenges. In addition to the identified challenges, this study has also contributed to an understanding of how these aspects can come to affect a collaboration.

Inspired by the digital revolution to the financial industry, the discussion around central bank digital currency also attract attention from academics and central banks. The People’s Bank of China (PBOC) is also researching on China’s CBDC: digital currency electronic payment (DCEP) and announced that DCEP would be issued as soon as possible.  However, the PBOC does not systematically disclose the information of DCEP. The characteristics and mechanism design are still obscured and need to be explored deeply. This thesis analysed the classification and mechanism design choices of DCEP from the perspective of two different demands: general demand and central bank demand. Based on pragmatism philosophy, we use a mixed-methods approach that is a combination of qualitative and quantitative research. Through the interview and surveys, we identified the demands from the PBOC and the general public in China and the characteristics of DCEP from official claims. Then generate the design choices via the money flower and the pyramid of CBDC models and compare the result with the demand. The analysis shows that the DCEP belongs to type B general-purpose CB digital tokens, and it would adopt a complex multi-layer hybrid architecture design, with the support from both DLT and conventional way. In conclusion, the current mechanism design choices can meet the demands from each side to a certain extent and reached a delicate balance under the trade-off between privacy and security issues. This thesis provides an insightful view on the classification and design choices of DCEP, fulfils the lack of systematic research relating to the demand and design choices of DCEP, and reveals the public’s insufficient knowledge in DCEP.

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. / Fenomenet isolerat värde i varje blockchain-system har blivit en distinkt frågaom blockchainfält. För att hantera detta problem kom kravet på interkommunikationmellan kedjor upp. I en smal mening hänvisar tvärkedjantill processen för interoperabilitet mellan tillgångar mellan relativt oberoendeblockchains. I denna avhandling analyserar vi huvudsakligen designprinciper,tekniska svårigheter och lösningar för interkommunikation mellan kedjor ien smal bemärkelse. Med introduktionen av distribuerad huvudboksteknologi(DLT) beskriver vi interaktionen med andra bokar som det grundläggandeproblemet med den nuvarande blockchain-tekniken.Tvärkedjans implementeringsform manifesteras huvudsakligen som tillgångsbyteoch överföring av tillgångar. Hittills finns det många befintliga applikationsscenarier och Pro projekt som antagits från dessa manifestation. Dettadokument kommer att fokusera på dessa två implementeringar, illustrera derasprinciper, lokalisera förståelsessvårigheterna och lägga fram motsvarandemöjliga lösningar. Sedan utarbetade vi åtta populära tvärkedjeprojekt underliggandemekanism listade med tre huvudkategorier. En detaljerad jämförelseberoende på deras driftskompatibilitetsnivå, konsensusalgoritm och tillämpningsscenarierav den övergripande översikten över 20 tvärkedjeprojekt presenterassom en tabell i Appendix A.Under genomförandeprocessen genomförde vi en enkel atomisk swap Cross-Chain ram baserad på hash Time lock kontrakt mellan Bitshares och Ethereum,sedan jämföra prestanda med en plånbok program som finns med Ripplemed Interledger Protocol. Dessa två applikationer föreställs de två olika användningsfallenav Cross-Chain genomförande.Med begränsade projekt att testa, nåddes vår slutsats efter en diskussion medrelativa fördelar med två metoder praktiskt taget. Interledger-protokollet haren bättre lösning med avseende på decentralisering, skalbarhet och huruvidadet stöder traditionella bokar.

Handeln med finansiella instrument har effektiviserats avsevärt under de senaste decennierna tack vare den tekniska utvecklingen och internationaliseringen. Pappersbaserade värdepapper har ersatts av digitala finansiella instrument och investerare kan numera på ett enkelt sätt skapa värdepappersportföljer innehållande komplexa värdepapper från hela världen. En välfungerande och effektiv handel med finansiella instrument förutsätter att förtroendet existerar mellan aktörer på finansiella marknader. Idag säkerställs förtroendet inom finansiella marknader av ett antal olika finansiella intermediärer, vilka ansvarar för olika funktioner såsom clearing, avveckling och kontoföring. Transaktionskedjan avseende finansiella instrument består därmed av flera nivåer och varje enskild transaktion måste genomgå samtliga nivåer. Den finansiella handeln har ökat betydligt i omfattningen och ett betydande antal transaktioner är numera gränsöverskridande. Detta har resulterat i ett tämligen komplext, sammanlänkat och sårbart system, vilket bland annat har synliggjorts under den senaste finanskrisen år 2008.     Blockkedjeteknologi, vilken är en typ av Distributed Ledger Technology, kan något förenklat ses som en databas eller ett transaktionsregister. Till skillnad från traditionella transaktionsregister, vilka i regel är centraliserade och förvaltas av olika intermediärer, bygger den nya teknologin på ett decentraliserat nätverk av aktörer utan att någon tredje part är ansvarig för verifiering av transaktioner. Blockkedjeteknologin introducerar därmed ett nytt sätt att genomföra transaktioner med digitala tillgångar, genom att förtroendet säkerställs med hjälp av kryptografiska lösningar och ett decentraliserat nätverk. Blockkedjeteknologin anses av många ha en betydande potential att effektivisera transaktionskedjan avseende finansiella instrument genom att exempelvis automatisera förandet av transaktionsregister samt integrera de olika nivåerna inom transaktionskedjan. Tekniken är dock fortfarande i en utvecklingsfas och många olika utmaningar återstår innan tekniken kan komma till användning. I Sverige präglas transaktionskedjan avseende finansiella instrument dessutom av strikta regleringar, varför frågan uppstår om huruvida lösningar baserade på blockkedjetekniken är förenliga med dagens rättsliga ramar.   I denna uppsats diskuteras huruvida och på vilket sätt blockkedjeteknologin skulle kunna effektivisera vissa funktioner inom transaktionskedjan avseende finansiella instrument samt vilka rättsliga frågeställningar som uppstår i samband med tillämpning av den nya tekniken utifrån dagens rättsläge i Sverige.