What is Scribe Optimistic?
ScribeOptimistic is a contract that builds upon Scribe, Chronicle’s novel Schnorr Oracle, providing additional optimistic poke functionality.
Chronicle Protocol's Oracle system, called
Scribe, is a first of its kind. It uses an efficient
Schnorr multi-signature aggregation mechanism. The signature aggregation scheme allows data compression, enabling multiple validators to produce a single Schnorr signature. This mechanism addresses the scalability issue of oracles and helps save on gas fees
by over 60% on L1 and over 68% on L2 vs Chronicle’s previous ECDSA iteration.
Chronicle’s ScribeOptimistic is designed for Layer 1 blockchains where computation is expensive, such as Ethereum Mainnet. On these chains, signature aggregation, an integral process for oracle networks, uses a lot of gas, making onchain verification of Schnorr signatures costly. To address this issue, ScribeOptimistic introduces an additional function called opPoke(), which enables offchain verification of Schnorr signatures.
How Does ScribeOptimistic Work?
With ScribeOptimistic all values optimistically proposed by the Oracle network validators are put into a public “buffer” and get automatically accepted after the challenge period has concluded. During the challenge period:
- Offchain Verification: anyone can verify the signature offchain
- OpChallenge(): if a challenger finds an invalid signature, the challenger can call opChallenge() to trigger an onchain verification
- Rewards and Accountability: successful challengers receive an ETH reward, the optimistic value is discarded, and the validator responsible for the invalid value is removed. This automatic kick ensures a validator has exactly one chance to push invalid data. They cannot exploit challenger wallets by repeatedly submitting invalid opPokes.
Incentivizing optimistic pokes: using ETH rewards to incentivize monitoring and challenging optimistic pokes
Scribe Optimistic provides a mechanism for incentivizing monitoring and challenging optimistic pokes. This is done through an ETH reward which is sent directly inside the opChallenge() transaction to the challenger if the opPoke is invalid. In other words, in the unlikely event a malicious value is reported, Chronicle Protocol will pay you to challenge the invalid data.
For checking the current challenge period, you can check the opChallengePeriod’s value using opChallengePeriod() which returns a value in seconds. Similarly, you can check the reward for successfully challenging the opPoke using the challengeReward().
This automated fraud-proof mechanism ensures that only correct values are finalized, while incentivizing participants to monitor the system.
Running a Challenger
Running a challenger is a permissionless process, meaning anyone can participate. The community is encouraged to run a challenger to help maintain the integrity of the ScribeOptimistic system. By doing so, participants contribute to the security and accuracy of Chronicle’s Oracle network while earning ETH rewards for any valid challenges.
