In a recent Twitter exchange, Ethereum co-founder Vitalik Buterin stirred up a conversation regarding the classification of various Layer 2 (L2) scaling solutions within the Ethereum ecosystem.
Specifically, Buterin contended that Ethereum’s “validiums” should not be considered genuine rollup solutions. This assertion has ignited a debate among blockchain enthusiasts and experts regarding categorizing L2 solutions and their underlying security models.
Validiums vs. Rollups in Ethereum’s scaling landscape
The discussion began when Daniel Wang, the founder of the Ethereum roll-up solution Taiko, posted a comment on Twitter. Wang argued that if an Ethereum rollup relies on another data chain, such as Celestia, for data availability, it should be categorized as a “validium.”
Validiums, unlike traditional ZK-rollups, do not post transaction data to Ethereum’s Layer 1 (L1) but instead rely on cryptographic proofs to validate transactions off-chain. This approach aims to enhance scalability by reducing the need to store full transaction data on the mainnet.
Vitalik Buterin supported Wang’s perspective, asserting that the core characteristic of a rollup is the provision of an unconditional security guarantee, ensuring that users can withdraw their assets even if all other participants conspire against them.
In contrast, this security guarantee cannot be maintained if data availability relies on an external system. Hence, Buterin believes such solutions should be categorized as validiums.
Validiums, like Celestia, use a modular blockchain structure composed of data availability and validation layers. These networks employ validiums to enable swift and private transactions. However, they do come with the caveat of relying on operators to post cryptographic proofs honestly, which may result in reduced data availability compared to traditional rollups.
Proposed terminological adjustments
Vitalik Buterin took to the decentralized social media platform Warpcast to share a diagram suggesting adjustments to some terminologies used in the blockchain industry. He proposed replacing terms like “security-favoring” and “scale-favoring” with “strong” and “light,” respectively, in an effort to make the terminology more concise.
This proposal met with mixed reactions within the Ethereum community. While some, like Ryan Berckmans, asserted that validiums should be considered Layer 2 networks, Buterin’s proposal challenged the conventional definitions.
Berckmans maintained that a Layer 2 chain should settle on Ethereum, regardless of the location of data availability. He expressed his readiness to debate anyone who insisted that data availability had to be on Ethereum for a solution to be categorized as L2.
Divergent views on the classification of Validiums
The debate surrounding the classification of validiums has not reached a consensus within the blockchain community. L2Beat, a platform specializing in industry analytics for Layer 2 solutions, has expressed a viewpoint contrasting Berckmans’. L2Beat argues that validiums, including Optimiums, do not qualify as L2s.
This stance is based on the premise that by not publishing data on Ethereum’s Layer 1, these solutions introduce additional trust assumptions on top of the blockchain’s existing security model.
The shifting landscape of Layer 2 solutions
The debate ignited by Vitalik Buterin’s comments underscores the evolving and dynamic nature of the Layer 2 scaling solutions ecosystem in the Ethereum network. As the blockchain industry continues to innovate, it is not uncommon for terminology and classifications to be revisited and redefined to accurately reflect emerging solutions’ distinct features and security models.
Layer 2 scaling solutions, which aim to alleviate congestion on Ethereum’s mainnet and enhance its overall scalability, play a pivotal role in the blockchain’s evolution. Rollups and validiums represent two approaches to achieving this goal, each with advantages and trade-offs.
