Speeding up block propagation in Bitcoin network: Uncoded and coded designs

This paper designs and validates new block propagation protocols 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). Besides the PoW consensus protocol, the other key aspect of Bitcoin that limits TPS is its networking protocol. In this work, we aim at redesigning the current Bitcoin's networking protocol to increase TPS without changing the vital components in its consensus-building protocol. In particular, this work improves the compact-block relaying protocol to enable the propagation of blocks containing a massive number of transactions without inducing extra propagation latencies. The improvements of this work consist of (i) replacing the existing store-and-forward compact-block relaying scheme with a cut-through compact-block relaying scheme; (ii) exploiting rateless erasure codes for P2P networks to increase the block-propagation efficiency. Since the protocols designed in this work only need to rework the current Bitcoin's networking protocol and do not modify the data structures and cryptofunctional components, they can be seamlessly incorporated into the existing Bitcoin blockchain. To validate the designs, we perform analysis on the protocols and implement a Bitcoin network simulator on NS3 to run different block propagation protocols. Our analysis and experimental results confirm that the new block propagation protocols could increase the TPS of the Bitcoin blockchain by 100x without compromising security and consensus-building.