High-Bandwidth Node Selection in Compact Block Relay

Blockchain has a scalability issue of low throughput. Improving throughput is in a trade-off relationship with an increase in the fork rate, which is an indicator of security. It is known that reducing the block propagation time is effective in solving this trade-off. In fact, a protocol called Compact Block Relay has been proposed and implemented for Bitcoin to reduce the block propagation time. In this study, we propose a method to select high bandwidth node in Compact Block Relay in order to reduce block propagation time. The result of the simulation shows that our proposed method improves the average block propagation time by 7.3% compared to what is implemented in Bitcoin Core. Furthermore, the proposed method is more resistant to attacks such as Eclipse Attack and TendrilStaller compared to existing Bitcoin Core implementations.