- The Ethereum Classic network has experienced two 51% chain attacks in just 6 days
- Consecutive 51% attacks on the network exposes the fragility of Ethereum Classic’s blockchain architecture
- A Bitquery investigation revealed that a massive amount of $1.68 million worth ETCs were double spent by the attacker.
In just a span of 6 days, the Ethereum Classic network has already experienced two 51% chain attacks. In the first 51% attack which took place on 1st of August, an enormous chain organization of 3693 blocks took place. However, a report revealed that the offender was offline for a period of 12 hours during which the 3000 blocks were inserted.
Although the first attack was considered a technicality of the mining software, another 51% attack that took place on 6th August rocked the Ethereum Classic network. A Bitquery investigation revealed that a massive amount of $1.68 million worth ETCs were double spent by the attacker. However, the attacker tried to double spend $3.3 million in which he ultimately failed. The investigation also revealed that the hashpower that was used for the attack had the same source as that of the first one.
Consecutive Attacks Exposed Fragility of ETC’s Design
However, in a recent Core Devs meeting the Ethereum developer team took up the recent attacks and discussed the effective measures to stop these 51% attacks from occurring in future. Consecutive 51% attacks on the network exposes the fragility of Ethereum Classic’s blockchain architecture. In order to exploit funds the attacker had only spent $20000 dollar. The security team was not alerted immediately and it took the ETC team days to recover from the attack.The developers also questioned the need of additional measures to protect the network and ETC’s funds from these attacks.
Blockchains Beyond the Specified Checkpoint Would be Rejected
The developers proposed to set several checkpoints at specific node levels. By doing so the history of each block would get stored and the blocks with higher levels beyond the specified checkpoint would be rejected by the nodes. Higher hashpower mining is commonly required for chain reorganization.
According to the Nakamoto’s Proof of Work consensus the blockchain with higher magnitude of PoW automatically supplants the original chain. Hence by setting up checkpoints, the threshold for the nodes would be reduced and there is a possibility of averting such attacks. However lowering this threshold to extremely low levels can have entirely different consequences, warned Ethereum Foundation’s Alexei Akhuniv.
ETC should just switch to proof of stake. Even given its risk-averse culture, at this point making the jump seems lower-risk than not making it.
— vitalik.eth (@VitalikButerin) August 6, 2020
Ethereum’s CEO Vitalik Buterin, advised ETC that they should switch to Proof of Stake consensus which is risk averse by nature.