ZK Fraud Proofs Available Now: An Incremental Step Toward Full ZK with Succinct Labs

We’re excited to announce that OP Stack rollups on Conduit can now implement ZK Fraud Proofs through our partnership with Succinct Labs and their new OP-Succinct Lite offering. ZK fraud proofs can move your rollup to Stage 1 decentralization, decrease finality time from seven days to one day, and allow you to take the first step towards full ZK proving. 

One Conduit rollup, Donatuz, has already committed to use ZK fraud proofs from Succinct, putting it among the first to adopt the technology. We expect others to follow as well, and look forward to supporting them as they help accelerate Ethereum’s ZK endgame. 

If you’d like to transition your rollup to ZK fraud proofs, contact us here. Keep reading to learn more about ZK fraud proofs work and how you can implement them on your rollup today.

How ZK fraud proofs work

You can think of ZK fraud proofs as a middle ground between the fraud proofs of the optimistic rollup model and the validity proofs of the ZK rollup model. A quick refresher: Under the optimistic model, a challenger has seven days to submit a fraud proof challenging the validity of rollup transactions in any given block submitted by the proposer, and the L1 smart contract checks the proof by replaying all transactions. The proposer or challenger loses their ETH bond if they’re incorrect.  Under the ZK model, the rollup provides a ZK proof immediately proving the validity of all transactions for each batch.

Source: Succinct Labs

Under the ZK fraud proof model, the rollup behaves as an optimistic rollup until a challenger submits a dispute. At that point, the proposer submits a ZK proof defending the validity of their block, and an L1 smart contract checks the proof and distributes the bond to whoever is right. In other words, ZK fraud proof rollups only turn to ZK proving when they really need it – in the case of a dispute.

Advantages of ZK fraud proofs

ZK fraud proofs come with several advantages over the standard optimistic model:

• Faster finality. While not as fast as ZK rollups’ 1 hour validity, ZK fraud proofs can reduce finality time from the optimistic model’s seven days to just one day, as the dispute resolution process is much faster.
• More capital-efficient due to lower bonds. The simplification of the dispute process to a single ZK proof also makes the bond size needed to secure the chain up to 20x lower. The rollup operator can operate with more capital-efficiency, and the challenger role becomes much more accessible, enhancing decentralization.
• Stage 1 decentralization. The use of open smart contracts for ZK fraud proof checking can satisfy the decentralization requirements for Stage 1 rollup designation.

ZK fraud proofs are also highly configurable, with rollups having the ability to customize finality times through a range of parameters – the default end-to-end setting is 24 hours. 

What about full ZK with validity proofs? While we remain steadfast that full ZK is the endgame for Ethereum rollups, the extra proving costs can be significant for some rollups. At a certain threshold of activity, rollups can distribute ZK proving costs across enough users and transactions to make them essentially negligible. But the extra cost per transaction is too high for many smaller rollups. ZK fraud proofs are an excellent option for those rollups to begin the ZK journey now and enhance their decentralization at a lower cost, then go full ZK later as their chains grow and ZK proving costs continue to fall.

Get ZK fraud proofs now

Conduit makes it easy to implement ZK fraud proofs from Succinct. If you’re launching a new chain, we can work with you during the setup process to add ZK fraud proofs quickly. If your chain is already up and running, we can switch you from the optimistic model to the ZK fraud proof model quickly, with virtually no extra effort on your part.

Contact us here to get Succinct ZK fraud proofs on your Conduit rollup.