During the 51% attack on Firo, a single miner gained enough mining power to rearrange blocks in the network.
We are under 51% attack at the moment. We recommend not to make transactions during this time until the network returns to a normal state. We will post updates when we have them. Note this is not a coding error but a nature of PoW. $XZC $FIRO
— Firo (formerly Zcoin) (@firoorg) January 20, 2021
The attacker rearranged the blocks
The privacy-focused cryptocurrency Firo (previously ZCoin) was hit by 51%. During the attack, a single miner obtained the majority hash power and rearranged the network blocks.
Changpeng Zhao, CEO of cryptocurrency exchange Binance, reported that the attacker successfully retrieved 306 blocks to prevent transactions on the blockchain.
Most Proof-of-Work (PoW) blockchains, especially small to medium-sized projects like Firo, are 51% vulnerable to attacks.
Similar attacks have taken place against other PoW blockchains, including Ethereum Classic, Grin, and BCHA in the recent past.
The damage is being evaluated
The Firo team is currently assessing the damage in discussions with exchanges and will report soon. Meanwhile, the team recommended that no action be taken until the network stabilizes.
According to the team, it plans to implement ChainLocks, a blockchain security protocol developed by the Dash project to prevent future 51% attacks.
The attack caused a significant drop in the FIRO token price, and immediately after the attack the price dropped from $ 5.50 to $ 4.86.