Faster Fraud-Proofing: Chronicle Halves ScribeOptimistic’s Challenge Period
Bianca Buzea
Bianca Buzea·
After a successful year and a half of ScribeOptimistic oracles, Chronicle lowered the challenge period for its ScribeOptimistic from 20 minutes to 10 minutes on January 28th, 2025. This marks a significant milestone in delivering faster updates while maintaining robust decentralized fraud-proof mechanisms.
Why Lower the Challenge Period?
Chronicle’s ScribeOptimistic fraud-proof system is the first of its kind in the oracle space.
ScribeOptimistic builds upon Scribe, Chronicle’s extremely gas-efficient Oracle based on aggregated Schnorr signatures. It enhances Scribe by adding an optimistic poke functionality, opPoke(). ScribeOptimistic is designed for Layer 1 blockchains like Ethereum Mainnet, where expensive calldata and network congestion can result in prohibitive gas costs.
The challenge period has been gradually reduced to ensure the system remains resilient and reliable. User safety is of the utmost importance at Chronicle, ScribeOptimistic has now had a year and a half of real-world operation in production. The first production test of opChallenge occurred on August 1st, 2024. We have seen that valid challenges are successfully issued in the block following the submission of an invalid signature; the equivalent of about 12 seconds.
This change in the challenge period aims to ensure prices are kept fresher while still effectively maintaining the same level of security and resilience.
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:
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.
This automated fraud-proof mechanism ensures that only correct values are finalized, while incentivizing participants to monitor the system.
Implications of a Shorter Challenge Period
Lowering the challenge period to 10 minutes offers several advantages and considerations:
Faster Updates: Users benefit from more frequent price updates
Lending Protocols: The “margin call” feature, enabled by the challenge period, allows users to predict liquidation events and take preventive actions. With a reduced challenge period, users must act more swiftly to adjust their positions in the event of a liquidation.
Looking Ahead
Chronicle’s transition to a 10-minute challenge period for ScribeOptimistic highlights the system’s strength and adaptability. For detailed guides and resources, visit our documentation portal to learn more about ScribeOptimistic and consider running a challenger to actively participate in the network.
Chronicle Protocol has a long history. Born in 2017, it is still one of the oldest, continuously operating protocols in the space. Scribe, on the other hand, is new and novel. But what is it? In this short piece, we will dive deeper into this novel Oracle design recently launched by the core contributors to Chronicle Protocol, Chronicle Labs.
