First time accepted submitter stanga writes "Cornell researchers unveiled an attack on the Bitcoin mining protocol that enables selfish mining pools to earn more than their fair share. In a technical report the authors explain this attack can be performed by a pool of any size. Rational miners will join this pool to increase their benefits, creating a snowball effect that may end up with a pool commanding a majority of the system's mining power. Such a pool would be able to single-handedly control the blockchain, violating the decentralized nature of the increasingly successful Bitcoin. The authors propose a patch to the protocol that would protect the system from selfish mining pools smaller than 25% of the system. They also show that Bitcoin can never be safe from selfish mining pools larger than 33% of the network, whereas it was previously believed that only groups larger than 50% of the network were a threat to the system. The question is — can the miners operating today adopt the suggested fix and dismantle too-large pools before a selfish mining pool arises?"