The Bitcoin Gold network reportedly underwent a ‘long-chain attack,’ also known as a 51 percent attack. But the development team claims that it promptly fended off the hostile takeover. The team also supplied mining pools and crypto exchanges with the latest version of BTG Core.
On Friday, July 10, the Bitcoin Gold team detected an ‘extremely long chain of over 1300 blocks’. The attackers had been mining this counterfeit chain since July 1 this year.
As per the emergency update, BTG folks sensed this 51 percent attack attempt on July 2. They alerted all crypto exchanges and Bitcoin Gold mining pools about it the very same day, and also supplied them with the latest version of the BTG Core software (version 0.17.2). The checkpoint stopped the attacker in their steps, and it came at block height 640650.
Apparently, the miscreant(s) had been renting power from NiceHash to mine the spurious chain. But as per the Bitcoin Gold developers,
Because those attacking blocks are anchored at a block mined on July 1st (before the checkpoint), the honest pools and exchanges who are running the updated code automatically rejected the attacker’s chain.
The Bitcoin Gold team released the information yesterday with a warning to everyone to upgrade nodes to the latest BTG Core version. For their timely response and effective management of this crisis, the devs received accolades on Twitter.
Public blockchains operate with ‘honest nodes’ harboring more than 51% of the network’s computational power. All these nodes contribute to keeping the correct version of the chain alive.
They do so by keeping themselves updated with the latest version of the blockchain containing all the latest transactional records.
But sometimes, ‘dishonest miners or nodes’ jack up their hash power to rewrite the original records and create a new blockchain. In this way, they make the cryptocurrency already spent available to them ‘again,’ thereby compromising the underlying consensus protocol.
Yesterday’s 51% attack on Bitcoin Gold is not the first such act. Ethereum Classic experienced a brutal 51% attack in January last year. A series of double-spend transactions led to pilferage of 88,500 ETC (~USD 460,000 at that time).
Coinbase was the first to detect Ethereum Classic’s deep chain reorganization, after which the cryptocurrency exchange reported it on their official blog.