A Study of Orphan Blocks in Public Blockchain

Orphan blocks are blocks mined by miner compliance but not confirmed by other peers. Major public blockchain systems such as Bitcoin and Ethereum face damage from orphaned blocks, and a low orphan block is a crucial metric for blockchains. In this work, we analyze the main factors of orphan block generation and survey the damage to orphaned blocks. We built a real environment of Ethereum in a local cluster to verify the percentage of orphan blocks in the PoW protocol. We observed that the highest rate of orphan blocks in nodes reached 81.91%, and 76.45% of all blocks mined by the cluster nodes were orphan blocks. Finally, we investigate the specific solutions to solve orphan blocks.