Vitalik Addresses Concerns on Ethereum's Security after Merger
Let me fill you up if you are new.
Ethereum is one of the largest smart contracting networks in the world. It is Turing complete, meaning developers can deploy code whose execution is automated once certain conditions are met.
As active as Ethereum is, it is now facing scalability challenges. At the same time, there are energy-efficiency questions, tasking operators of proof-of-work chains like Ethereum, Bitcoin, and others.
Ethereum has initiated plans to shift to Proof-of-Stake, a consensus algorithm without miners. It will be several folds more energy efficient than any protocol using Proof-of-Work.
In this period of transition, there were concerns that malicious miners could compromise the Ethereum primary chain by running custom clients. These could be allegedly bribed to shortly organize the canonical order of the chain, causing chaos.
Vitalik, in a post on July 20, said this wouldn't be possible because miners are often community members. As such, their interests are aligned, incentivizing good behavior. The co-founder says attacking the primary chains from which they draw benefits is counter-productive.
Second, after the merger, it would be incredibly hard for a small group of isolated miners running modified clients to reorganize a block on their own. There would be cost, risk, and difficulty limitations rendering such futile actions economically unfeasible.