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.

In today’s centralized identity systems, large companies control and store user datain a centralized manner, which poses a risk to users’ privacy and personal data. Self-sovereign identity (SSI) decentralizes digital identity management and gives individu-als full control over which personal data is shared and with whom. Furthermore, SSIenables verifiable credentials, allowing companies, authorities and individuals to buildnetworks of trust among themselves. This thesis discusses SSI, as well as a project whereSSI is practically applied in a mobile software application project for the distribution ofdigital drink tickets. The goal of the project is to develop a prototype to demonstratehow SSI can be applied in a general application, that involves issuing a verifiable cre-dential in the form of a drink ticket. To realize the project goal, an application has beendeveloped in React Native, where several frameworks for SSI have been studied. ”AriesCloud Agent Python” (ACA-Py) has been integrated with a REST API to provide SSIfunctionality to the project. The project has resulted in a working mobile applicationthat can issue and verify digital drink tickets, stored in the digital wallet application ofthe ticket holder. Minimal personal data is shared with the application, and only withthe exclusive approval of the ticket holder. The result confirms the potential of SSI fordecentralized identity management. / I dagens centraliserade identitetssystem är det stora teknikföretag som lagrar och kon-trollerar användardata, vilket medför en risk för användarnas integritet och personligadata. ”Self-sovereign identity” (SSI) decentraliserar digitala identiteter och ger indivi-den full kontroll över vilka personliga data som delas och till vem. Vidare möjliggörSSI verifierbara legitimationer, där förtroendenätverk byggs mellan företag, myndig-heter och individer. Denna uppsats avhandlar SSI, samt ett projekt där SSI appliceratspraktiskt i en mobilapplikation för distribution av digitala dryckesbiljetter. Målet medprojektet är att utveckla en prototyp för att visa hur SSI kan appliceras på en generellapplikation som innebär utgivande av en verifierbar legitimation i form av en dryckesbil-jett. För att realisera målet har en applikation utvecklats i React Native, där flera ramverkför SSI har studerats. ”Aries Cloud Agent Python” (ACA-Py) har integrerats genomREST API för att tillhandahålla SSI-funktionalitet till projektet. Projektet har resulterati en fungerande mobilapplikation som kan utfärda och verifiera digitala dryckesbiljetter,som lagras på en biljettinnehavares digitala plånboksapplikation. Minimal personligdata delas med mobilapplikationen och med innehavarens exklusiva tillstånd. Resultatetbekräftar potentialen av SSI för decentraliserad digital identitetshantering.