Block withholding (BWH) attacks are a known threat to cryptocurrency mining pools. Classical analyses have focused on block-dependent reward schemes, where miners are paid only when the pool itself discovers a block. A new arXiv paper shifts attention to the pay-per-share (PPS) scheme, which the abstract notes is used by most contemporary mining pools.
The paper examines an "all-out" attack variant, in which a malicious miner deliberately withholds discovered blocks to damage the pool's revenue. Under PPS, payouts are based on submitted shares rather than block discoveries, so the attacker's incentives differ from those in older reward models. The authors derive an optimal strategy for conducting such an attack under this scheme.
The work provides a theoretical foundation for assessing the vulnerability of modern mining pools to block withholding. As PPS becomes increasingly common, understanding how rational attackers behave under this reward structure is important for both pool operators and participants seeking to secure their operations.