tl;dr
Optimism, a leading layer-2 blockchain, is introducing "fault proofs" to its mainnet, addressing a long-standing security issue. This technology aims to ensure the accuracy of transaction data and power decentralized withdrawal mechanisms, enhancing trust in Ethereum's operator network. With fault p...
Optimism, a leading layer-2 blockchain, is introducing "fault proofs" to its mainnet, addressing a long-standing security issue. This technology aims to ensure the accuracy of transaction data and power decentralized withdrawal mechanisms, enhancing trust in Ethereum's operator network. With fault proofs, users can rely on Ethereum for fund withdrawals, rather than the rollup network's internal systems. The implementation of fault proofs marks a crucial advancement for Optimism, signaling a shift towards greater decentralization. Other chains using Optimism's technology will also benefit from this upgrade.
Optimism, a leading layer-2 blockchain, aims to help Ethereum users transact quickly and for lower fees. Its tech serves as the foundation for some of the biggest names in blockchain, including the Coinbase exchange's popular Base blockchain and Worldcoin's World Chain–from OpenAI founder Sam Altman. But for years, Optimism had a problem. All of the blockchains that used Optimism's technology were built according to a core underlying premise: They "borrowed" Ethereum's security apparatus. In reality, however, that wasn't the case. Until now, Optimism has been missing a core feature at the heart of its security design: "Fault proofs." On Monday, that long-promised tech is finally coming to Optimism's mainnet.
HOW DO ‘FAULT PROOFS’ WORK? Over the past two years, layer-2 rollup networks like Optimism have become the go-to method for operating on the notoriously expensive Ethereum blockchain. When a user submits a transaction to a rollup network, it is bundled with transactions from other users before it is passed down to Ethereum. Those bundles are written to Ethereum's transaction ledger all at once, a setup that lets users transact faster and for just a fraction of the fees. In theory, rollup transactions are secured by "proofs," which are cryptographic methods that allow observers on Ethereum to check whether transaction details have been recorded accurately. This is most relevant in the context of withdrawals, allowing users to trust Ethereum–rather than the rollup network–to pull their funds out of the layer-2 chain. Without fault proofs, users who deposited their funds into Optimism needed to trust the rollup's "security council" to return their funds–a system that exposed the rollup to potential human error or bias. With fault proofs, those users should only need to trust Ethereum.
The Optimism team previously shared in March that it was testing its fault proofs system on their Sepolia testnet. Since then, they had an audit conducted by blockchain security firm Sherlock, and found a few bugs that they were able to patch out. “So we fixed everything that we did find, and we got a lot of confidence in the actual implementation being ready for prime time,” Floersch said. Starting this week, the network will again rely on a fault-proof system to power withdrawals, but it will still retain "training wheels" meant to ensure that things run smoothly. The Security Council will remain intact and can intervene in the event that the fault-proof system goes down. This combination of the two entities is what Optimism is calling “Stage 1 decentralization.” The goal is to eventually reach Stage 2 decentralization, where the network will not have to rely on the Security Council at all.
With fault proofs finally shipping to Optimism's mainnet, other chains that use Optimism's OP Stack will gain access to the tech as well. (According to DefiLlama, Two blockchains that use Optimism's OP Stack, Blast and Base, currently surpass Optimism's mainnet in terms of total value locked.) “We're going to start with OP mainnet for this upgrade, it's a decently large upgrade,” Floersch told CoinDesk. “However, it should not be too long” for Coinbase's Base chain to implement the fault proof system, too, Floersch added.