Is The Future of Ethereum Centralised and Censored?

**Friederike Ernst** (0:00)
Welcome to Epicenter, the show which talks about the technologies, projects and people driving decentralization in the blockchain revolution. I'm Friederike Ernst, and today I'm speaking with Thomas Thiery, who is a researcher at the Ethereum Foundation.

**Thomas Thiery** (0:11)
I think being very careful that Ethereum preserves the permissionlessness and social resistance properties that it has is very important to me. Every slot, you select 16 validators randomly, and these validators just have to look at the public mempool basically and make lists of transactions. The attesters will basically see the inclusion list, they take the union of all transactions in it, and then they check whether the builder block includes these transactions or not. And if it doesn't, based on what they saw, just like don't vote for the block. And the block like never makes it on train basically. So it's sort of a valid condition for the block. There was also a very meaningful intent in the design of Fossil not to involve MEV. The whole Fossil design was like, OK, if we want this to be forced and social resistance, we have to prevent it from being crowded out by MEV transactions.

**Friederike Ernst** (1:08)
I'm Friederike Ernst, and today I'm speaking with Thomas Thiery, who is a researcher at the Ethereum Foundation and one of the authors of EIP 7805, which is Folk Choice Enforced Inclusionists, abbreviated to Focil. Focil makes censorship stop working by letting validators flag transactions that must be included. So blocks that leave them out simply don't get included into the chain. Hey Thomas, it's so good to have you on.

**Thomas Thiery** (1:35)
Hello, thanks for having me.

**Friederike Ernst** (1:39)
Cool. Maybe we'll dive right in. So if you had to summarize Focil in one sentence for people who are familiar with the Ethereum core protocol, how would you characterize it?

**Thomas Thiery** (1:53)
Yeah, very briefly, I think Focil helps to drastically improve inclusion guarantees for public transactions by letting multiple validators that are selected randomly basically to force include lists into Ethereum blocks. So each validator is selected randomly and they are going to make list of transactions and these transactions basically have to go in the block. Otherwise, the block is not made canonical, so it just won't be voted on by attestors. And so by using this sort of like mechanism, you ensure that transactions that are like basically pending in the mempool are included, which is very good for improving transaction inclusion guarantees, I guess, and just reduce vectors of censorship.

**SPEAKER_3** (2:51)
This episode is brought to you by Gnosis, building the open Internet one block at a time. Gnosis was founded in 2015 and it's grown from one of Ethereum's earliest projects into a powerful ecosystem for open user owned finance. Gnosis is also the team behind products that had become core to my business and that of so many others like Safe and Cowswap. At the center is Gnosis Chain. It's a low fee layer one with zero downtime in seven years and secured by over 300,000 validators. It's the foundation for real world financial applications like Gnosis Pay and Circles. All of this is governed by Gnosis DAO, a community run organization where anyone with a GNO token can vote on updates, fund new projects and even run a validator from home. So if you're building a Web3 or you're just curious about what financial freedom can look like, start exploring gnosis.io.

**Friederike Ernst** (3:43)
What made you passionate about this topic in particular? And how big a problem do you think censorship is today on Ethereum?

**Thomas Thiery** (3:54)
So what made me passionate about it is, I feel like that's one of the core, very sort of like central properties of what Blockchains are made for. Before MEV basically came into the scene, we like validators were all doing everything. Like they were building blocks, proposing blocks, attesting like all the sort of duties a validator is supposed to do. Then there was MEV and basically there was a big centralization force caused by MEV. And so we were basically worried that validators that were decentralized would sort of like centralize because of that force. The solution to this was PBS, so Proposer Builder Separation. You have like, you separate sort of like the validating, validator role from the builder role. And that was good for so many reasons. But like one of the reasons that was not anticipated maybe enough is that like builders were actually very centralized. I feel like we lost a bit of this property because now you have very dominant builders building most of the blocks on Ethereum. There are like no checks and balances to make sure these builders don't censor. They can basically censor freely without like any checks and balances, which is sort of like not exactly what blockchains are for. Yeah, I think sort of like being very careful that Ethereum preserves the permissionlessness and censorship resistance property that it has is very important to me.