Smart contracts are software systems that monitor and control the execution of legal contracts to ensure compliance with the contracts' terms and conditions. They often exploit Internet-of-Things technologies to support their monitoring functions, and blockchain technology to ensure the integrity of their data. Ethereum and business blockchain platforms, such as Hyperledger Fabric, are among the most popular choices for smart contract development. However, there is a substantial gap in the knowledge of smart contracts between developers and legal experts. Symboleo is a formal specification language for legal contracts that was introduced to address this issue. Symboleo specifications directly encode legal concepts such as parties, obligations, and powers. This thesis proposes a tool-supported method for translating Symboleo specifications into smart contracts. Its contributions include extensions to the existing Symboleo IDE, the implementation of the ontology and semantics of Symboleo into a reusable library, and the Symboleo2SC tool that generates Hyperledger Fabric code exploiting this library. Symboleo2SC was evaluated with three sample contracts. Experimentation with Symboleo2SC shows that legal contract specifications in Symboleo can be fully converted to smart contracts for monitoring purposes. Moreover, Symboleo2SC helps simplify the smart contract development process, saves development effort, and helps reduce risks of coding errors.

Yes / Insurance claims processing involves multiple entities and data sources, necessitating communication between human agents. Consequently, vehicle insurance claims have traditionally required significant human effort and time. Daily vehicle-related transactions, including those managed by transportation authorities, pose challenges for tracking. Centralised systems have been utilised for national solutions, but trust management, transparency, and access control issues arise. There is potential for further integration of vehicle-related transactions. This article proposes a blockchain framework for vehicle insurance to streamline the reporting of accidents and filing of insurance claims. Blockchain-based automation platforms can enhance the scale and response time of claims processing, providing users with control over additional transactions, inspection, and insurance. For experimental purposes, a blockchain was created using Hyperledger Fabric to store information about vehicles, owners, and insurance. Efficient querying of this blockchain requires specific participants, assets, and transactions. The consensus algorithm can identify invalid claims if a transaction request contains an error. By deploying blockchain technology and smart contracts, this architecture has the potential to address trust and security concerns associated with traditional insurance policies and claims.

Blockchain technology is a booming new field in both computer science and economicsand other use cases than cryptocurrencies are on the rise. Permissioned blockchains are oneinstance of the blockchain technique. In a permissioned blockchain the nodes which validatesnew transactions are trusted. Permissioned blockchains and distributed databasesare essentially two different ways for storing data, but how do they compare in terms ofperformance? This thesis compares Hyperledger Fabric to Apache Cassandra in four experimentsto investigate their insert and read latency. The experiments are executed usingDocker on an Azure virtual machine and the studied systems consist of up to 20 logicalnodes. Latency measurements are performed using varying network size and load. Forsmall networks, the insert latency of Cassandra is twice as high as that of Fabric, whereasfor larger networks Fabric has almost twice as high insert latencies as Cassandra. Fabrichas around 40 ms latency for reading data and Cassandra between 150 ms to 250 ms, thusit scales better for reading. The insert latency of different workloads is heavily affected bythe configuration of Fabric and by the Docker overhead for Cassandra. The read latency isnot affected by different workloads for either system.

The adoption of Blockchain technology looks promising in many areas. However, it is still a relatively new area of research, and implementations are not entirely free of challenges. This study focuses on the potential benefits of blockchain adoption in the public sector, with the potential to enhance democratic processes. Blockchain technology is, by design, apt at managing several significant challenges regarding communication and security in digital networks. This includes maintaining data integrity, enhancing security and privacy, and to mitigate fraud and manipulation. Possible issues that might arise when applied to the public sector is regarding law and regulation compliance. To cover the current state of the field, an exploratory literature review has been conducted. Among the results are several interesting blockchain projects around the world with emphasis on civic dialogue. Studying possible network architectures it appears that Hyperledger Fabric is the most prominent when it comes to implementations in the public sector. Based on this study, and on input from experts within the field, a proposed model that could be implemented and tested on a smaller scale is presented. The purpose is to record and track expenditures on public sector projects and make them available to the public. / Antagandet av Blockchain-teknik ser lovande ut på många områden. Det är dock fortfarande ett relativt nytt forskningsområde, och implementeringar är inte helt fria från utmaningar. Denna studie fokuserar på de potentiella fördelarna med blockchain-tillämpningar i den offentliga sektorn, och dess potential att förbättra demokratiska processer. Blockchain-tekniken är designad för att hantera flera viktiga utmaningar när det gäller kommunikation och säkerhet i digitala nätverk. Detta inkluderar upprätthållande av dataintegritet, förbättrad säkerhet och integritet för att minska risken för bedrägerier och manipulation. Möjliga problem som kan uppstå när de tillämpas på den offentliga sektorn handlar om efterlevnad av lagar och förordningar. För att täcka fältets nuvarande tillstånd har en undersökande litteraturstudie genomförts. Bland resultaten finns flera intressanta blockchain-projekt runt om i världen med tonvikt på medborgardialog. När man studerar möjliga nätverksarkitekturer verkar det som att Hyperledger Fabric är den mest framträdande när det gäller implementeringar i den offentliga sektorn. Baserat på denna studie och på input från experter inom området presenteras en föreslagen modell som kan implementeras och testas i mindre skala. Syftet är att registrera och spåra utgifter för projekt inom den offentliga sektorn och göra dem tillgängliga för allmänheten.

This thesis presents an extension to Hyperledger Fabric, a private blockchain system, allowing historic transactions to be pruned without peer coordination. The feature is facilitated via pruning predicate functions, provided along any smart contracts a given system is desired to host. An evaluation of the extension demonstrates its impact, in terms of memory saved, for a specific asset delivery use case. It is concluded that the gains of pruning historic transactions from blockchain systems could yield significantly reduced storage requirements for some categories of applications, especially such with low transaction interdependency. It is also suggested that the deterministic consensus algorithms used by Hyperledger Fabric makes the transaction histories it may maintain not strictly required, meaning that the particular set of transactions that must survive pruning depend on what properties a blockchain is expected to maintain.

Product certificates are sent throughout the supply chain of Swedish heavy industry in order to show provenance and physical characteristics of objects such as screws. The data management of the certificates has been, and still is, a very manual process. The process requires extensive work in order to maintain a correct record of the certificates. In particular, tracing causes of errors and establishing compliance takes a long time and effort. The company Chaintraced is developing an application to automate the process by acting as a third party to digitalize and manage the certificates. Introducing a third party into a business-to-business process requires that data integrity is preserved and that information reaches its expected destination. Recent research has indicated that distributed ledger technologies showpromise to fulfill these requirements. In particular, blockchain-based systems offer immutability and traceability of data, and can reduce the trust needed between different parties by relying on cryptographic primitives and consensus mechanisms. This thesis investigates the application of distributed ledger technology to further automate the Swedish heavy industry supply chain and reduce the trust needed in a third party managing the certificates. Requirements for an industrial strength system is set up and several distributed ledger technology solutions are considered to fit the use case of Swedish heavy industry. A proof of concept based on the findings is implemented, tested and compared with a centralized database to explore its possible usage in the supply chain with regard to feasibility, immutability, traceability and security. The investigation resulted in a prototype based on Hyperledger Fabric to store product certificates. The solution provides certain guarantees to immutability and security while being developed with feasibility for deployment in mind. The proposed solution is shown to be slow compared to a centralized solution but scales linearly with number of certificates and is considered within bounds for the use case. The results also show that the proposed solution is more trustworthy than a centralized solution, but that adopting blockchain technology is an extensive task. In particular, trustworthiness and guarantees provided by the solution is highly dependent on the feasibility aspect and the investigation concludes that adoption of blockchain technology within the Swedish heavy industry must take this into consideration. / Hanteringen av produktcertifikat inom den svenska tungindustrin är en mycket manuell process vilket resulterar i att ett enormt arbete krävs för att upprätthålla en korrekt hantering av certifikaten. Att spåra orsaken till fel och att kontrollera efterlevnaden av krav inom industrin tar lång tid. Chaintraced har utvecklat en applikation som automatiserar hanteringen av certifikaten genom digitalisering och att som tredje part lagra informationen. Att introducera en tredje part i affärsverksamheter kräver att integriteten av datan bibehålls och att information anländer till korrekt mottagare. Ny forskning har visat att distribuerade liggare har möjligheten att uppfylla dessa krav. Framförallt gällande blockkedjetekniken med dess många egenskaper och garantier som företag letar efter, så som oföränderlig och spårbar data. Blockkedjetekniken reducerar också förtroendet som behövs för parter inom nätverket genom att förlita sig på kryptografi och konsensus mekanismer. Den här rapporten utreder användningen av distribuerade liggare för att ytterliggare automatisera den svenska tungindustrins leveranskedja och minska tilliten som krävs för en tredje part som hanterar certifikaten. Krav ställs upp för ett system och flertalet distribuerade databastekniker undersöks för att passa in i fallet angående den svenska tungindustrin. En prototyp är utvecklad baserad på kraven, prototypen är testad och jämförd med en central databas för att undersöka hur implementationen står sig vad gäller genomförbarhet, oföränderlighet, spårbarhet och säkerhet. Undersökningen resulterade i en prototyp baserad på Hyperledger Fabric. Prototypen lagrar produktcertifikaten och ger vissa garantier till oföränderligbarhet samt säkerhet. Möjligheten för aktörer i kedjan att använda prototypen hade stor inverkan på hur systemet utvecklades. Prototypen visar sig vara långsammare än en centraliserad lösning men mätningarna kan anses vara inom kraven för ett system inom tungindustrins leveranskedja. Skalbarheten av lösningen är beroende av kraven på säkerhet men är linjär i antalet certifikat som skickas och lagras. Resultaten visar också att den föreslagna lösningen inger mer tillit än en centraliserad lösning men att introducera blockkedjetekniken är en komplex process. Trovärdighet och garantier som ges av lösningen är till stor del beroende av komplexiteten vilket rapporten kommer fram till är det viktigaste för svensk tungindustri att ha i åtanke vid eventuell antagande av blockkedjeteknik.

A smart contract is a recently emerging technology which enables agreement to be automatable by computers and enforceable by legal enforcement or tamper-proof execution of code. A majority of smart contracts are run on the blockchain which enables smart contract transactions without a central authority. Smart contract implementation contains several challenges which makes implementation more difficult. The problem is that organisations struggle to implement smart contracts due to the absence of documentation, standardisation, and guidelines making it difficult to know how a smart contract should be implemented. Additionally, it is unclear what capabilities and tools are required for smart contract implementation. Therefore, it is challenging for organisations to assess their own competence of smart contract implementation. This thesis aims to develop a Smart Contract Maturity Model (SCMM). The purpose of the model is to clarify the functionalities and capabilities required to implement a smart contract while also offering organisations the ability to assess the smart contract implementation competency. This improves the adoption of smart contracts. Through the help of the design science framework, the SCMM emerged from the thesis. Applying design science included explicating the problem, defining requirements, designing and developing the artefact, demonstrating and evaluating the artefact. A literature survey was used to explicate the problem and to define requirements for the maturity model. Furthermore, a case study including interviews were used to refine the requirements and to demonstrate and evaluate the SCMM. The SCMM includes maturity levels, generic goals and practices, specific goals, key processing areas and practices, tools, glossaries and smart contract examples. Inspired by the Capability Maturity model Model Integration for Development (CMMI-DEV), the maturity levels of the SCMM consisted of initial, foundation, managed, defined, quantitatively managed and optimising. The identified key processing areas were stakeholder capabilities, resources and tools, platform, contract implementation, standards, laws and terminology and security. Although there were several limitations, the SCMM contributed to the field of smart contracts by closing the gap of previous research and improving the adoption of smart contracts.