Enhancing data security in the Internet of Things with blockchain Enhancing data security in the Internet of Things with blockchain Ενίσχυση της ασφάλειας δεδομένων στον Διαδίκτυο των Πραγμάτων με αλυσίδες συναλλαγών Διπλωματική Εργασία Diploma Work 2022-10-182022enThe Web of Things (WoT) initiative aims at unifying the world of interconnected devices over the Internet. With the significant increase of IoT, there is a great need for easy, fast, and secure access to data that can be exploited and offer useful information to users with the responsibility or authority to handle this data. However, current blockchain-backed IoT systems use the blockchain to store access control policies for sensor data stored in a database. In this Thesis, we propose iBot, a blockchain architecture that validates and verify the identity of IoT devices, data, and applications. The difference with current blockchain-backed IoT systems is that the iBot creates a safe environment to develop applications based on data produced by IoT devices. We use blockchain technology to protect the data of the devices, users, and services from unauthorized access. We use Decentralized Identifiers (DID) and Verifiable Credentials (VC) that W3C proposes for User/IoT Authorization & Authentication to achieve this. The architecture encompasses different functionalities to serve a 3-tier architecture model, each serving different functionality for different types of users (Infrastructure Owners – System Administrators, Application Developers, Customers). It supports storage for subscriptions to sensors and their data for real-time updates, and with the help of the blockchain, there is a reliable recording of the use of the system by each user. iBot uses the Hyperledger Fabric framework as the blockchain back-end and also extends the idea that devices have OpenAPI descriptions, adding to the description and the smart contract definition to protect the device's data. The experiments show that the architecture can cope with a large workload in real time without losing information.Προπτυχιακή Διπλωματική Εργασία που υποβλήθηκε στη σχολή ΗΜΜΥ του Πολ. Κρήτης για την πλήρωση προϋποθέσεων λήψης Προπτυχιακού Τίτλου Σπουδώνhttp://creativecommons.org/licenses/by/4.0/Πολυτεχνείο Κρήτης::Σχολή Ηλεκτρολόγων Μηχανικών και Μηχανικών ΥπολογιστώνPateritsas_Anastasios_Dip_2022.pdfChania [Greece]Library of TUC2022-10-17application/pdf2.6 MBfree Pateritsas Anastasios Πατεριτσας Αναστασιος Petrakis Evripidis Πετρακης Ευριπιδης Ioannidis Sotirios Ιωαννιδης Σωτηριος Samoladas Vasilis Σαμολαδας Βασιλης Πολυτεχνείο Κρήτης Technical University of Crete Cloud computing