Two Bitcoin Cash (BCH) pools reverse the transactions of another miner with the attack known as “51% Attack”.
In the 51% attack, the attackers successfully obtain more than 51 percent of total hash power and ability to manipulate the public ledger (Blockchain).
The attack was done after the hardfork of Bitcoin Cash (BCH) on 15 May. BTC.com and BTC.top mining pools carried out the attack to stop a miner to transfer the coins that are not supposed to be there. That day the attack was initiated Bitcoin Cash (BCH) chain was split into two chains.
Cryptocurrencies like Bitcoin Cash (BCH), where the majority of hash power is controlled by a single entity or a group, allows them to manipulate the public blockchain, change the transactions and carried out new transactions.
51% attack is a serious topic for a cryptocurrency, nowadays it’s easy to carry out a 51% attack on small crypto coins due to the decline in hash rates.
Earlier BTC.top alone have more than 50 percent of the total hash power which allow them to run the network on their demands. According to Coin.Dance the two mining pools now shares a 44 percent of total hash rate.
The 51% attack was done for the good of the community, not to steal the coins for themselves or introduce new code in the blockchain. Not everyone in the BCash (BCH) community agrees on that, Bitcoin Cash Developer Kiarahpromises, published in an article on May 17:
“To coordinate a reorg to revert unknown’s transactions. This is a 51% attack. The absolutely worst attack possible. It’s there in the whitepaper. What about (miner and developer) decentralized and uncensorable cash? Only when convenient?”
Bitcoin podcast host Guy Swann explains on twitter:
“Since the original split in 2017, there has been a significant number of coins accidentally sent to ‘anyone can spend’ addresses (due to [transaction] compatibility of sigs, but no #SegWit on #BCH), or possibly they’ve been replayed from #Bitcoin onto the #BCH network,”
The code was changed during the hardfork on 15 May, these coins become spendable. The unknown miner tries to take the coins that were stopped by BTC.top and BTC.com by reversing the transaction.
Swann Further added:
“When the unknown miner tried to take the coins themselves, [BTC.top and BTC.com] saw & immediately decided to re-organize and remove these [transactions], in favor of their own [transactions], spending the same P2SH coins, [and] many others,”
Some of the Bitcoin Cash users support the re-org of the Blockchain. Jonathan Silverblood Bitcoin Cash supporter said:
“This is a very unfortunate situation, but it is also what proof of work actually is. The miners in this case did choose to drop prohashes block and from what I heard, it is because they deemed a transaction within it to have been invalid”
Bitcoin is the most secure cryptocurrency available now. The decentralization of bitcoin also has questions “almost half of the Bitcoin total hash power is shared by three mining pools only.