Bitcoin SV (BSV) was reportedly hit by a so-called 51% attack in the late afternoon yesterday. As a result of the attack, three chains mined at the same time. Coin Metrics took to Twitter to report on the attack.
Lucas Nuzzi of Coin Metrics explains in a tweet that an attempt was already made the day before yesterday to attack the network. The next attempt yesterday succeeded after a huge amount of hash power, or computing power, was unleashed on the network. Nuzzi explains:
“BSV is going through a massive 51% attack.
After an attempted attack yesterday, a serious amount of hash power was unleashed at 11:46 AM today and the attackers are now succeeding.”
FARUM has identified a 51% attack today on the BSV network at around 11:45AM EDT.https://t.co/Oy19UDw53t https://t.co/T3MMRHqPe8
— CoinMetrics.io (@coinmetrics) August 3, 2021
The attack would have lasted at least three hours. As a result of a 51% attack, there is a chance that BSV has been spent twice. “All BSV deposits exchanges received during the attack may have been spent twice,” Nuzzi said.
Shortly after the attack, there was great uncertainty at the BSV mining pools. At that time it is unclear which chain is the right one. In addition, the attackers would have managed to reorganize up to 14 blocks.
51% attack
A 51% attack is something where a lot proof-of-work (PoW) fans fear. Although in networks like Bitcoin (BTC) virtually impossible due to the costs involved, smaller networks like Bitcoin SV are more vulnerable due to less computing power.
The 51% refers to the proportion of computing power that the attackers need to take over the network. Once the bad miners have the majority, 51%, of the hash rate, they can mine faster than the good miners.
Bitcoin SV protocol dictates that the longest chain is the real one. So if the bad miners secretly mine faster in the background than the good miners, and suddenly broadcast their chain over the network, the ‘bad’ chain will become the real one. The attackers can thus reverse the transactions made during the attack and reissue the BSV.
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