Efficient Blockchain Scheme for IoT Data Storage and Manipulation in Smart City Environment

We describe an implementation of a data storage and manipulation system for the Internet of Things (IoT) networks based on blockchain and using a Practical Byzantine Fault Tolerance (PBFT)-like protocol to achieve consensus. In our proposed model, blockchain ledger consistency is ensured by leaders contending for the next available spot(s) in which the newly accepted blocks will be appended to the blockchain. The contention takes place on a shared overlay accessible to all leaders nodes. We use a multiple-entry PBFT to eliminate the need for a dedicated leader node and the delays involved in changing leaders in different rounds. Our model allowed the multiple leaders to work in parallel to propose blocks using dedicated overlay networks. The performance of the proposed scheme is analyzed through an analytical model that employs a discrete-time Markov chain and M/G/1 queuing model with exhaustive limited service. The results obtained from the model confirm the efficiency of the proposed model in a wide range of parameter values and show that the proposed model outperforms the multiple entry points of the PBFT protocol with single block insertion.