August 4, 2021, | AtoZ Markets – Yesterday, August 3, a 51% attack was made on the Bitcoin SV cryptocurrency network. According to analysts, 14 blocks were reorganized. The attack was initially reported by CoinMetrics analyst Lucas Nuzzi on the evening of August 3.
BSV is going through a massive 51% attack.
— Lucas Nuzzi (@LucasNuzzi) August 3, 2021
After an attempted attack yesterday, some serious hashing power was unleashed today at 11:46AM and attackers are succeeding.
Over a dozen blocks are being reorgd & up to 3 versions of the chain being mined simultaneously across pools.
According to his words, yesterday at about 11.45 am on the network suddenly appeared "serious hashing power." CoinMetrics later confirmed this information and stated that its FARUM blockchain security monitoring tool recorded the reorganization of 14 blocks in the Bitcoin SV network. CoinMetrics noted that the attack is over, but the impact on mining pools is still there. As of the evening of August 3, the pools were mining coins at "completely different" block heights, Nuzzi said.
What is a 51% attack?
A 51% attack allows an attacker to gain partial control of the blockchain. It can be used for a double-spend attack, with the attacker's chance of success being maximized. Another possibility of a 51% attack is disruption of the blockchain through full or partial stopping of transaction confirmation.
The essence of the attack is that an attacker obtains more than 50% of the hash rate in blockchains using PoW, or 50% of coins in blockchains using PoS. The greater the percentage of control he can get, the faster and more successful the attack will be. Having an advantage over other miners or validators, an attacker can create an alternative blockchain and overwrite a certain number of recent blocks with the transactions he needs.
On the evening of August 3, The Bitcoin Association recommended that node operators mark the attacker's blockchain as invalid. The Bitcoin SV blockchain, which emerged as a result of the Bitcoin Cash hard fork, was subjected to four attacks in July. It is not yet clear who is behind the attack. CoinMetrics is examining a chain of attackers looking for “traces of double spending on exchanges,” Nuzzi said.
According to him, the main Bitcoin SV mining pools are still trying to get work done and mine blocks on the same chain.
According to Bitinfocharts, from Monday to Tuesday Bitcoin SV hash rate fell by almost 50%.
However, Nuzzi believes that this is a consequence of the confusion after the reorganization of the blocks. Last spring, analysts reported that Bitcoin Cash and Bitcoin SV became vulnerable to a 51% attack after halving the reward to miners.
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