Speeding up Block Propagation in Bitcoin Network: A Cut-through Relaying Scheme

Abstract

We design and validate a new block propagation protocol for the peer-to-peer (P2P) network of the Bitcoin blockchain. Despite its strong protection for security and privacy, the current Bitcoin blockchain can only support a low number of transactions per second (TPS). In this work, we redesign the current Bitcoin's networking protocol to increase TPS without changing vital components in its consensus-building protocol. In particular, we improve the compact-block relaying protocol to enable the propagation of blocks containing a massive number of transactions without inducing extra propagation latency. This improvement is achieved by replacing the existing store-and-forward compact-block relaying scheme with a cut-through compact-block relaying scheme. Since our protocol only needs to rework the current Bitcoin's networking protocol and does not modify the data structures and crypto-functional components, it can be seamlessly incorporated into the existing Bitcoin blockchain. To validate our design, we implement a Bitcoin network simulator on Network Simulator-3 (NS-3) to run different block propagation protocols. The experimental results confirm that our new block propagation protocol could increase the TPS of the Bitcoin blockchain by 100x without compromising security and consensus-building.