Enhancing IoT Security with Blockchain

This thesis explores the emerging technology of blockchain and its applications in IoT. Blockchain is an interdisciplinary technology build on top of Cryptography, Distributed Systems and Computer Network. It creates a secure environment that allows some certain types operations and interactions among participants to be trustworthy. It establishes security on top of objective cryptographic assumptions and security proofs, instead of subjective trust assumptions. In this thesis proposal, we first narrate our understanding on blockchain, then present our exploratory works on using blockchain to enhance IoT and real-life security. The first work is Normachain, where we allow the supervisors to search for illegal information on top of encrypted blockchain transactions without decrypting it, thus preserving the confidentiality of the transaction content at the same time. The second work is Tokoin, where we design a coin-based access control scheme to address the long-existing overprivilege challenge and weak auditability problem in the field of IoT access control. In the third work we extend on-chain trust to off-chain by achieving the real time data consistency between physical objects and their corresponding digital entities on blockchain. We also fully implement a trusted monitoring system to support our example of trustworthy physical vaccine shipping