It has been reported that Vitalik Buterin, co-founder of Ethereum, stated that the core security property of the blockchain is that "even in the event of a 51% attack, it cannot turn invalid blocks into valid ones"; therefore, even if validators collude, they cannot steal user assets. However, he pointed out that this characteristic does not apply to off-chain trust scenarios—when validators are granted powers that exceed the control of the chain itself, if 51%.