A rare “51% attack” on the cryptocurrency blockchain may have been successful, raising huge questions about its security and future.
Crypto exchange Coinbase suspended Ethereum Classic trading after detecting a potential attack on the tokens underlying technology.
According to Coinbase, the reorganisation of the blockchain has led to the attacker taking control of tokens worth £460,000.
The blockchain is intended to be a distributed, transparent, and immutable ledger which uses cryptography to mathematically verify transactions and ensure everyone’s trust in the currency.
However, it has long been theorised that an attacker who controlled more than 51% of the mining on the network could purposefully choose to double-spend certain coins.
Dr Patrick McCorry, assistant professor of computer science at King’s College London, said of the attack: “The issue in a 51% attack is that a single person has more than half the network’s computational power (i.e. they have a much bigger warehouse of computers) and they can create blocks faster than everyone else.
“What happened in Ethereum Classic is that a single person managed to repeat the entire network’s effort for 100 blocks, create a longer blockchain and reverse a transaction that paid out around $460,000”.
One mining group controlled up to 60% of the Ethereum Classic network during the course of the supposed attack, although investigations are ongoing as to the results of it.