Vitalik Buterin: Celestia-backed L2s are Validiums, Not Genuine Rollups

Ethereum co-founder Vitalik Buterin has initiated a discussion on classifying various layer-2 scaling solutions. He contends that the validiums on the blockchain are not authentic rollup solutions. In an X (previously Twitter) exchange this week, Buterin agreed with Daniel Wang, Taiko founder, that the rollup solution on Ethereum is Ethereum’s caladiums are not a bona fide rollup solution.

Rollup Realities: Buterin’s Unconditional Security Standard

Wang’s remarks on Ethereum rollups and their inclusion of external data chains, including the proposed modular blockchain Celestia, elicited agreement from Buterin. ‘That’s right,’ replied Vitalik Buterin in response. “At the heart of what it means to be a rollup is an unconditional security guarantee: you can always get your assets out even if everyone else colludes against you.”

“You can’t get that if data availability has its availability depend on some external system,” he said.

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Validiums are Ethereum scaling solutions using zero-knowledge proofs, allowing for off-chain transactions while leaning on the security and verification of Ethereum’s mainnet. Unlike zero-knowledge rollups, which process transactions on an L1 verification layer-2 network like Ethereum, validium networks adopt a distinct strategy.

They refrain from posting the actual transaction data to an L1. Instead, they cryptographically prove that transactions are valid, aiming to attain higher scalability by not storing full transaction data on-chain.

However, one disadvantage of validiums is the dependence on operators to faithfully post proofs, possibly lowering data availability compared to rollups. Celestia and similar platforms utilize a modular blockchain designed with data availability and validation layers. These systems incorporate validiums to facilitate rapid and private transactions.

On January 16, Buterin proposed adjustments to industry terminologies in a post in Warpcast, suggesting that the wordings “strong” vs. “light” could be used as opposed to “security-favoring” and “scale-favoring” to make it more concise.

Validium Vortex: Discord Emerges Over Layer-2 Definitions

Not all members of the Ethereum community agree with Buterin’s stance. Ryan Berckmans, an Ethereum community participant, emphasized that validiums should be regarded as layer-2 networks. He added,

“A layer-2 is a chain that settles on Ethereum.” I’ll debate anyone who insists the DA [data availability] has to be on Ethereum for it to be an L2.”

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According to L2Beat, a layer-2 industry analytics platform, validiums are not actual layer-2 solutions despite what Berckmans has in mind. As L2Beat puts it,

“Validiums and Optimiums are not L2s: by not publishing data on L1, they introduce additional trust assumptions on top of it.”

The ongoing argument highlights the constantly evolving nature of the blockchain space. Its participants are actively shaping the fundamental terms of their transactions.

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