Ethereum co-founder Vitalik Buterin proposed three ways to address what he described as potential system complexities at the heart of Ethereum’s proof-of-stake consensus mechanism.
He posted on
The main problem is that the validators who keep the network running must produce a large number of signatures - digital signatures using cryptography - as part of the process of keeping the network running. This is already a considerable amount of work for the network, but as more validators join the network, this will increase the number of signatures and place a greater burden on the system. According to current plans, subsequent upgrades will significantly increase signature requirements. (The Block)