Security of dynamic authorisation for IoT through Blockchain technology

Sammanfattning: The use of Internet of Things devices is an integral part of our modern society. Communication with internet of things devices is secured with asymmetric key encryption that is handled by the centralized certificate authority infrastructure. The emerging Blockchain technology now provides a safe way to change ownership of digital resources through a decentralized system that challenges the traditional centralized view of trust in digital systems. This project studies the security of building public key infrastructures and access communication protocols on Blockchain technology for IoT devices. An informal cryptographic analysis that used proof by contradiction showed that it is cryptographically safe to build Blockchain based Public Key Infrastructures. The analysed Blockchain based public key infrastructure was implemented with smart contracts and tested on the Ethereum platform along with a dynamic access control protocol ensuring dynamic authentication and distributed logging. The project also concluded that advancements in the software clients of nodes are required before Blockchain can be used in Internet of Things devices. This is due to the high storage demands required by currently available nodes.