MC Sharding: An Efficient Blockchain Sharding Based on Minimum Cut

Hui Wang, Wei Xiao Zhang, Yu Zhen Yang, Lan Yan Hu, Donghui Hu

Abstract: The application of sharding is of significant help to improve the scalability of blockchain. The existing sharding system puts too much emphasis on the isolation of zones, which to a certain extent increases the isolation between zones and brings additional load. In this paper, we propose a sharding approach based on the Minimum Cut Method (MC sharding), which is a complete sharding. The number of connections inside each zone is essentially the same. The evaluation results show that MC sharding is more secure and scalable than the existing system, with 1.5 times higher transaction throughput and significantly lower stale block rate in a blockchain system with 4000 nodes and 6 shards. Most importantly, MC sharding can be applied in practice very quickly because it does not change the main procedure of Bitcoin and the block data structure.