Since its launch in August 2021 with its built-in security feature, Arbitrum’s mainnet has remained untouched by any fraud proof submissions, as confirmed by Ed Felten, the co-founder and chief scientist of Offchain Labs, the team behind Arbitrum.
Arbitrum operates as an Ethereum layer-2 solution, employing an interactive multi-round fraud proof mechanism. This mechanism allows a layer-1 verifier contract to assess the validity of a challenger’s fraud-proof submission. When a submission is found to be valid, the fraudulent validator faces the consequence of having their stake slashed.
The purpose of fraud proofs is to address situations where challenging validators suspect that another validator has fraudulently or incorrectly assembled a batch of incoming transactions for the next block.
Remarkably, since its inception, Arbitrum’s mainnet has not seen a single attempt at a fraud proof, let alone a successful challenge, as revealed by Felten during Korean Blockchain Week on September 4th.
It’s noteworthy that both Arbitrum and Optimism function as optimistic rollups, albeit with differing approaches to fraud-proof mechanisms. Arbitrum employs a multi-round process, resulting in longer confirmation times but greater security, while Optimism adopts a single-round approach, leading to faster validations.
Felten explained that the scarcity of fraud proof attempts can be attributed to the substantial risk faced by malicious validators, who risk losing their entire stake. The strong disincentive to attempt fraud proofs has effectively deterred any such endeavors.
To bolster its security measures, Arbitrum introduced the ‘BOLD’ protocol (Bounded Liquidity Delay) on August 3rd, which introduces permissionless validation for Arbitrum chains. This advancement aims to reduce reliance on permissioned validation and significantly enhance decentralization.
Felten also revealed that there is currently a select group of approximately 12 validators participating in the fraud proof game. However, he expressed optimism that Arbitrum’s fraud proof feature will soon transition to a permissionless model, allowing anyone to contribute to the chain’s correctness by initiating challenges.
In summary, Arbitrum’s journey in the realm of fraud proofs has been uneventful thus far, with a clear path towards increased decentralization and security on the horizon