Polygon Nightfall

EY And Polygon Unveil ZK and Optimistic Rollup Hybrid

Accounting firm Ernst & Young and Ethereum scaling company Polygon has launched the mainnet beta of its rollup for businesses, Nightfall.

Ernst & Young (EY), one of the ‘Big Four’ financial services behemoths, started work on Nightfall in 2019 to make its customers’ Ethereum transactions private. But the company was so swamped by Ethereum’s high gas fees that in September 2021 it started working with Polygon to cut the costs of those private transactions.  

On May 17, the pair deployed the beta version of Nightfall’s third iteration. Nightfall 3 is a rollup – a scaling solution that collects batches of transactions, settles them on another blockchain, then rolls them up into a single transaction on Ethereum. Rollups benefit from Ethereum’s security while cutting costs and speeding things up.

Nightfall is a hybrid of two popular types of rollups: privacy-preserving zero-knowledge proofs, which only publicly disclose the time and date of a transaction, and optimistic rollups, which assume the transactions are accurate but allow validators to contest them. ZK rollups are faster but optimistic rollups are similar to the Ethereum Virtual Machine, making things easier for developers.

Polygon said Nightfall can be applied to things like supply chain management, private NFT marketplaces, and blockchain mixers. EY is already using Nightfall to develop software that lets businesses trace their supply chains. Polygon and EY want to release the finished version of Nightfall by 2023.

Vitalik Buterin has long emphasized the importance of zero-knowledge technologies for scaling Ethereum. ZK proofs have featured in Ethereum’s roadmap since 2016. But so far, optimistic rollups have emerged as Ethereum’s leading Layer 2s so far. According to L2beat, optimistic rollups Arbitrum and Optimism represent 66% of the sector’s $5B in total value locked combined.

Polygon said ZK proofs comprise its “strategic bet moving forward.” Last August, Polygon allocated $1B to build on zero-knowledge proofs. It merged with ZK scaling solution Hermez the same month, and in November announced an EVM-compatible rollup, Polygon Miden. In December came recursion ZK proof Polygon Zero, and in March a piece of ZK-powered ID software.