The fourth largest cryptocurrency BitcoinCash (BCH) blockchain apparently hit by 51% attack by two miners. Guy Swann one of the crypto community member and a podcast host of Cryptoconomy tweeted on May 24.
As per the tweet, the attack was functioned by the two mining pools BTC.top and BTC.com as they possess the majority control (a majority of the hash rate) of the BCH network. So, to stop the unidentified miner who was trying to take the coins which were transferred to the address “anyone can spend”. The two miners in an ostensible effort tried to reverse another miner’s transactions to undo the attackers’ transaction attempt.
Reportedly, during the bitcoin cash hard fork (system upgrade) the BCH network got split into two and due to this chain split the new software at block no. 582,679, as per BitMEX Research’s Forkmonitor tool got a bug. This bug further affected the bitcoin cash mempool. After that seemingly the new code released by the developers to fix the bug.
“When the unknown miner tried to take the coins themselves, http://BTC.TOP & http://BTC.COM saw & immediately decided to re-org & remove these [transactions] TXs, in favor of their own TXs, spending the same P2SH coins, + many others … So just 2 miners, in secret & w/ no trouble, took it upon themselves to remove 2 blocks w/ another’s TXs, & replace with their own.”
Another tweet came from Steinberg while expressing his views which states that decentralized systems can also be affected because they are some way of the other depends on the single codebase. The programmers can also make the mistakes and this can further affect the rest of the blockchain and its related software in an unexpected way.
The statistics and cryptocurrency services website Coin.Dance shows the stats of BTC.top and BTC.com which are holding approx. 44% of bitcoin cash hashing power when combined together.
51% attack Implies:
On proof of work blockchain like bitcoin (BTC), bitcoin cash (BCH) also involves miners to validate the transactions and join new blocks. Here 51% attack happens when somebody has the majority of the mining power on a proof-of-work which give access and maximum control to the block verifier. The maximum access to the miner enables him to reverse the transactions and this hashing power can also further prevent the other users from mining.
Attack on Ethereum Classic (ETC) Jan 2019
Allegedly, this year in Jan, the Ethereum Classic (ETC) blockchain also underwent a 51% attack, consequently followed in a loss of 54,200 ETC. Gate.io, the cryptocurrency exchange, and its researchers acknowledged that an attacker had proficiently reversed four transactions. However, the exchange indicated to pay the damages to the affected users. The platform also recommended other trading platforms to block the transactions instigated by the attacker’s address.