Ethereum Classic (ETC) experienced a 51% attack from 9 p.m. Jan. 6 to just after midnight on Jan. 7, resulting in a blockchain reorganization hundreds of blocks deep. The news of the attack has pushed ETC’s price down by 7 %, shaving off $40 million off its market cap.
We can confirm that there was a successful 51% attack on the Ethereum Classic (#ETC) network with multiple 100+ block reorganization. We recommend all services to closely monitored the chain and significantly increase required confirmations.
— Bitfly (@etherchain_org) January 7, 2019
The number of double spends during this 51 percent attack, if any, is unknown at this time. For now, it is recommended to wait for 400 plus confirmations before accepting any Ethereum Classic (ETC) transaction.
To all exchanges and mining pools please allow a significantly higher confirmation time on withdrawals and deposits (+400)
— Ethereum Classic (@eth_classic) January 7, 2019
ETC in trouble
Ethereum’s Constantinople hard fork
— Big Red Machine ??? (@xrpizzle) January 7, 2019
It is interesting to note the timing of this 51 percent attack, just a week before Ethereum Constantinople hard fork. Enough time for the developers to block ASIC miners by including ProgPoW in the fork.
Left as nearly stranded as possible, the new upgrade on ETH will not only leave ETH miners faced with slashed block rewards, but the ASICs may be blocked with ProgPoW all thanks to the ETC 51% attack.