Bitcoin SV has suffered another 51% attack beginning around 11:45 am EDT on Tuesday resulting in up to three versions of the chain being mined simultaneously, as initially reported by analytics firm It is the fifth such attack on the network since late June.

Fast facts

  • Further reporting by the firm reported all of Bitcoin SV FARUM nodes recorded “a deep reorg with a max depth of 14 blocks,” and while there haven’t been any further reorganization events, synchronization conflicts were still occurring on major mining pools.
  • A 51% attack refers to an attack on a blockchain by a group of miners who gain control of more than 50% of the hashrate — or computing power — of a proof-of-work blockchain. When functioning properly, new blocks of transactions are added when the network collectively agrees those transactions are valid.  If a single entity controls more than half of the total hashrate in the network, however, they are able to create their own blocks, regardless of the validity of the transactions as majority rules.
  • Attacks such as these on BSV pose a serious risk for proof-of-work blockchains, which includes Bitcoin as well as Ethereum in its current version. Ethereum Classic suffered a series of 51% attacks in quick succession in August 2020, disrupting more than 10,000 blocks and costing millions of dollars in losses. Furthermore, it was a significant reputational blow to such networks who many previously believed to be immutable and “unhackable.” These examples are far from the only 51% attacks to have occurred, as privacy-centric Grin was hacked in November 2020, and Bitcoin Gold, Verge and Monacoin fell victim in 2018.
  • A controversial hard fork of the Bitcoin Cash blockchain in November 2018, Bitcoin SV stands for “Satoshi’s Vision” — a reference to the pseudonymous creator of Bitcoin, Satoshi Nakamoto. BSV is led by Craig Wright, an Australian blockchain entrepreneur who claims he is Satoshi Nakamoto, but his claim were widely debated and debunked in the blockchain industry. In the wake of these attacks, Bitcoin SV was suspended from several crypto exchanges, including Huobi and OKEx, suggesting the possibility of further suspensions in the wake of this latest attack.