The Ethereum Classic (ETC) blockchain has experienced a second 51% attack in a week.
Bitfly, the parent company of Ethermine mining pool, reported the attack on Thursday morning. Binance also confirmed the reorganization of more than 4,000 blocks on ETC at block number 10935622. As a result, both Bitfly and Binance have halted ETC payouts, withdrawals and deposits.
A 51% attack or reorganization of a blockchain occurs when a group of miners controls more than 50% of the network's hash rate or computing power. This allows them to prevent new transactions from gaining confirmations, halt payments between users, as well as reverse transactions that were completed, meaning they could double-spend coins.
Today's attack is the second 51% attack on ETC in just five days, followed by the one …