Shrec: bandwidth-efficient transaction relay in high-throughput blockchain systems.

The success of Bitcoin and Ethereum has attracted many efforts to build high-throughput blockchain systems. This paper focuses on transaction dissemination --- a rather overlooked issue in these systems. We argue that efficient transaction dissemination is the key for a blockchain system to sustain at high-throughput --- usually thousands of transactions per second --- and the existing solutions fell short at doing so.This paper presents Shrec, a novel transaction relay protocol for high-throughput blockchain systems built around a hybrid transaction hashing scheme that has a low hash collision rate, is resilient to collision attacks, and is fast to construct. Our experiments demonstrate that when propagating transactions, Shrec utilizes network efficiently: compared to alternative designs, Shrec reduces the bandwidth consumption by 60% at modest CPU overhead and improves the system throughput by up to 90%.