Vitalik Buterin is turning his attention to a part of Ethereum that most users have never thought about, but that has quietly become one of its biggest pressure points: who decides which transactions go into a block.
In a new blog post on Monday, the Ethereum co-founder laid out a series of ideas aimed at preventing block construction (the process of assembling transactions before they are completed on-chain) from becoming too centralized.
While Ethereum’s upcoming “Glamsterdam” upgrade will officially implement the separation of proposers and builders, which will allow validators to outsource block construction to a competitive market, Buterin believes that simply creating a builder market will not solve all problems. If a few builders dominate, they can still censor transactions or extract huge profits from users.
One of the proposals, called FOCIL, would serve as an anti-censorship backstop. Under this design, a small group of randomly selected participants will each select the transactions that must be included in the next block. If these transactions are missing, the block will be rejected. The idea is that even if a single hostile builder controls the entire market, they cannot permanently exclude specific users.
Another focus of his post was so-called “toxic MEVs,” where traders exploit the visibility of pending trades to front-run or “flank” users’ trades. One potential solution is to encrypt transactions until they are finalized to prevent opportunistic actors from seeing them in advance.
Buterin also pointed to risks at the network layer, where transactions can be observed by intermediaries before they even reach a block, suggesting that anonymous routing systems could become an important line of defense.
In the longer term, he outlines a vision of a more distributed block building, where not every transaction requires full global coordination. He believes that most of Ethereum’s activity may not need to be processed in a single, tightly ordered package, which opens the door to designs that reduce central choke points.
Overall, Buterin seems to be focusing on the fact that as Ethereum scales, the decentralization challenge is shifting away from validators and towards the infrastructure that determines where user transactions actually take place on-chain.
Read more: Vitalik Buterin reveals his bold new plan to solve Ethereum’s scaling problems
