51% attack; majority attack
A blockchain attack where an entity controlling more than 50% of the network's computing power can disrupt transactions, such as double-spending or blocking confirmations.
The possibility of a successful 51% attack on the Bitcoin network is extremely low.
Small-scale cryptocurrencies are vulnerable to 51% attacks.
Standard technical spelling using the percent sign.
Spelling with パーセント written out; less common but still seen.
From English '51% attack', a term in cryptocurrency and blockchain technology.