#️⃣ [Analysis] Selfish mining in Ethereum - Jianya Nin and Chen Feng

Jianya Nin and Chen Feng of the University of British Columbia analyze selfish mining in Ethereum ($ETH), claiming through both theory and empirical research that Ethereum is more vulnerable than Bitcoin ($BTC). Selfish mining is the pooling of hashing power to increase rewards. In Proof-of-Work (PoW) systems like Bitcoin and Ethereum, a certain threshold of mining power must be reached before rewards are large enough to justify selfish mining. Selfish mining, furthermore, can have different ends: controlling the ledger to allow double spending--as in a 51% attack--or pooling hashing to gain extra rewards versus other miners. While Bitcoin has only to worry about the former, Ethereum has both problems. Nin and Feng find Ethereum's uncle and nephew reward system, which was designed to limit centralization in mining, actually do the opposite. Simulating a system of 1000 miners in 10 mining sessions of 100,000 blocks, Nin and Feng show that miners have an incentive to mine selfishly at just 16.3% of the total hashing power. While not against uncle and nephew rewards per se, Nin and Feng argue that a change to the reward structure is necessary to decrease the probability of selfish mining.