Novel Lightweight Consensus Protocol for Reaching Blockchain Consensus in Low Bandwidth Network Environment

As blockchain technology makes rapid progress, attempts to use it in various environments are also increasing. Especially home networks and smart factories consisting of a small network of Internet of Things (IoT) devices with singlehop or a few hops are trying to adopt blockchain systems to guarantee the integrity of data and to protect privacy. However, in such low-bandwidth network environments, they encounter challenges because of the network cost for block consensus. This study proposes a lightweight blockchain consensus protocol suitable for these environments. The proposed protocol improves the existing PBFT protocol to reduce the network cost required for consensus. The main innovation is to reduce the number of phases for consensus from three phases to two phases while preserving Byzantine failure tolerance. These two phases guarantee the total order of clients’ transactions in the same view. And the simple viewchange process in the proposed protocol enables the change of the primary node for new block generation. The experimental result shows a significant performance improvement of block consensus over the PBFT. Using the proposed protocol can contribute to operating blockchain systems in various lowbandwidth network environments. Keywords—blockchain, consensus protocol, lightweight protocol, low bandwidth network, PBFT