In a recent blog post, Ethereum co-founder Vitalik Buterin has suggested that teams currently developing zero-knowledge (ZK) Ethereum Virtual Machines (EVMs) should revisit Plasma, a once-prominent Ethereum layer-2 scaling solution. Plasma, a class of blockchain scaling solutions introduced in 2017, offers the potential for significant scalability gains by allowing most data and computation to be kept off-chain.
Plasma’s Role in Ethereum’s Evolution
While Plasma saw various iterations, it has largely been overshadowed by rollups due to issues like large client-side data storage costs and fundamental limitations that hinder generalization beyond payments. However, Buterin believes that the emergence of validity proofs, specifically zero-knowledge succinct non-interactive arguments of knowledge (ZK-SNARKs), could address these challenges.
Validity proofs could efficiently handle the main challenge faced by Plasma for payments – client-side data storage. They also provide tools to run an EVM on a Plasma-like chain, although limitations remain for complex applications.
The blog post delves into extending Plasma ideas, focusing on the simplest version, Plasma Cash. This model treats each coin as a separate non-fungible token (NFT), allowing for efficient tracking of ownership. It addresses the potential risks associated with operator misbehavior, emphasizing the need for prompt user exits.
The article explores challenges in applying Plasma to fungible tokens and proposes solutions to optimize coin transfers and exits. Additionally, it discusses the complexities of extending Plasma to the Ethereum Virtual Machine, highlighting the absence of clear ownership in many state objects.
Buterin suggests that validity proofs can simplify Plasma designs by proving the validity of each Plasma block on-chain, addressing concerns related to unavailable blocks and history challenges. He also highlights the potential for instant withdrawals in the common case.
While acknowledging the prominence of rollups in the current landscape, Buterin argues that Plasma’s ability to circumvent data availability issues makes it an underrated design space, especially with the development of ZK-EVMs. He encourages further exploration of the Plasma design space to enhance user protection and simplify the developer experience in 2023.