IBWH: An Intermittent Block Withholding Attack with Optimal Mining Reward Rate

Junming Ke, Pawel Szalachowski, Jianying Zhou, Qiuliang Xu, Zheng Yang

Abstract: A trend in clustering mining power into mining pools in proof-of-work (PoW) blockchain systems raises severe concerns on the stability and security of these systems. Such pools can misbehave by strategically withhold found solutions (i.e., blocks). It has been shown that the reward of a large malicious mining pool can be significantly increased by deviating from the honest mining strategy. Moreover, a malicious pool can launch the block withholding (BWH) attack making the target’s pool reward system unfair by letting malicious participants receive unearned shares while pretending to contribute work. Although these attacks are well-known, they are usually investigated in a simplified static reward model.