A blockchain-based integrated and interconnected hybrid platform for Smart City ecosystem

There has been an increasing demand for shaping the world’s cities into smart cities by adopting modern technological solutions. In recent times, Blockchain has emerged as a most promising technology with a wide range of applications, and its adoption to several smart city solutions is also observed. However, these existing blockchain-based smart city solutions are restricted to individual sectors only, and there is a lack of connectivity and composability among them. This makes them incapable of providing hassle-free services which involve multiple sectors. In fact, a fully-fledged smart city solution demands the integration of different solutions pertaining to different sectors, leading to a seamless interaction among its stakeholders across the boundary. To this aim, in this paper, we propose a hybrid blockchain-based platform to foster a complete smart city solution with the integration of different crucial sectors involved in the functioning of the smart city. We design an architecture for multiple blockchain networks to connect and share information among themselves through intra- and inter-blockchain communication, enabling citizens to avail inter-blockchain services as well. We also address the security and privacy aspects of intra- and inter-network transactions. We present our working prototype using Hyperledger Fabric and Node.JS. The empirical evidence acquired from system benchmarks and load testings is encouraging, with an enhanced throughput for intra-blockchain transactions on Hyperledger Fabric, compared to the Ethereum blockchain platform. To the best of our knowledge, this is the first proposal of its kind, addressing the integration of different smart city sectors through interconnected blockchain networks.