Glossary
Selfish Mining
A PoW attack where a miner hides newly mined blocks to mine on top of them privately, then releases the longer private chain to invalidate honest competitors' blocks.
Selfish mining, introduced in a 2013 Cornell paper by Ittay Eyal and Emin Gün Sirer, undermines the assumption that the honest chain always wins. A miner with significant — but not majority — hashrate withholds blocks they find, mines on their private fork, and releases the longer fork later to invalidate honest blocks.
The attack increases the miner's share of rewards relative to their hashrate. Bitcoin's design partially mitigates it through random tie-breaking, but selfish mining remains a theoretical risk that scales with hashrate concentration.