  We design and validate 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). 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 latencies. Our
improvements 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
block-propagation efficiency. Since our protocols only need to rework the
current Bitcoin's networking protocol and does not modify the data structures
and crypto-functional components, they can be seamlessly incorporated into the
existing Bitcoin blockchain. To validate our designs, we perform analysis on
our protocols and implement a Bitcoin network simulator on NS3 to run different
block propagation protocols. The analysis and experimental results confirm that
our new block propagation protocols could increase the TPS of the Bitcoin
blockchain by 100x without compromising security and consensus-building.
