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Arbitrum’s fraud proofs haven’t been used in the two years since it launched

Offchain Labs co-founder Ed Felten said there were one or two fraud challenges submitted on a version of Arbitrum running on the Ethereum proof-of-work fork after the Merge, which was defeated.

Not a single fraud proof has been submitted on Arbitrum since it first launched its mainnet with the built-in security feature in August 2021, according to Ed Felten, co-founder and chief scientist of the Arbitrum-building Offchain Labs.

Operating as an Ethereum layer-2, Arbitrum’s interactive, multi-round fraud proofs work by allowing a layer-1 verifier contract to decide whether the challenger’s fraud-proof submission is valid. If so, the fraudulent validator’s stake is slashed.

Fraud proofs are submitted by challenging validators when it considers another validator to have fraudulently or otherwise incorrectly assembled an incoming batch of transactions into the next block.

However, Arbitrum’s mainnet is yet to see a fraud-proof attempt let alone a successful challenge, Felten told Cointelegraph at Korean Blockchain Week on Sept. 4:

“Not on mainnet. We did have one or two on Ethereum proof-of-work (POW). After the Merge, [...] there was a version of Arbitrum running on the Ethereum POW fork and somebody did try to steal all the data and there was a successful challenge which defeated that.”

Felten said few fraud proof attempts have been made because malicious-intended validators are risk losing their entire stake.

“If any one person notices it and disputes your claim then you will surely lose your stake, so there’s a stronger disincentive to try,” Felten added.

Felten said there’s currently a permission set of validators — roughly 12 — that participate in the fraud proof game.

He also added that Arbitrum is rolling out a new iteration of the fraud proofs called “BOLD” protocol — (Bounded Liquidity Delay) which he says gives Arbitrum a faster guarantee for challenges.

“In the current version [...] an adversary who's willing to sacrifice multiple stakes can arrange to cause “N” weeks of delay if they're willing to sacrifice “N” stakes [...] But the BOLD protocol says no matter how many stakes they sacrifice, they'll be defeated in about eight days.”

Related: Arbitrum founder says Stylus is a game changer for EVMs

Arbitrum’s BOLD protocol was rolled out by Offchain Labs on Aug. 4.

Felten said Arbitrum’s fraud proof feature will soon be permissionless, allowing anyone to push towards ensuring the correctness of the chain when challenges are made.

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Artbitrum founder says Stylus is a game changer for EVMs

The Arbitrum-building Offchain Labs co-founder Ed Felten said its new tool would allow more seasoned devs to build EVMs, possibly making them safer.

A recently released tool for Arbitrum developers could onboard more devs to Ethereum Virtual Machines (EVM) and improve its code, says Offchain Labs co-founder Ed Felten.

Speaking to Cointelegraph at Korea Blockchain Week, Felten lauded Arbitrum Stylus, which Offchain released on a testnet on Aug. 31, allowing developers to use languages including Rust, C, and C++ to build Arbitrum apps.

Felten said Stylus would allow non-Web3 native devs to “use the languages and the development tools that they're used to.”

He added it would onboard “a lot more developers” to building EVMs with more mature tools and cited the larger number of devs that program in Rust over Solidity — the latter being the programming language for building Ethereum smart contracts.

“One of the things that comes from those much more mature tools is it's much faster. So it's 10 to 15 times faster for typical computations than EVM.”

According to Felten, the benefit of supporting legacy languages is the amount of code that already exists written in languages such as Rust which is already “battle-tested and audited.”

Felten identified Rust as a language that was designed to help catch development errors, with its tools being “really good at reducing the odds that you'll introduce a bug in your code.”

“You can just use it. Now you can use that directly on-chain. You're gonna build less from scratch and you're gonna be able to take better advantage of things that other people have done.”

Felten also highlighted the gas cost was 10 to 15 times lower, which allows for “more complex stuff [to be] done in the same transaction” and opens up the possibility of being able to perform iPhone-compatible cryptography.

Related: Decentralized asset management system launches for Arbitrum, Optimism

Felten explained that iPhones use a different digital signature standard than Ethereum, which is not supported well, so “cryptography on Ethereum that’s compatible with the iPhone has an extremely high gas cost.”

“But in Stylus, you can drive that down so it becomes really feasible. It’s not prohibitively expensive.”

This could give way to having a crypto wallet integrated on an iPhone — unlocking the ability to use Apple’s FaceID to verify wallet transactions similar to bank card purchases.

Other use cases Felten saw with the lower gas fees were higher levels of realism in blockchain-based games and the on-chain evaluation of machine learning models against live application data.

Ultimately, Felten thought Stylus could help burgeoning projects ship faster as allowing for mature programming languages means they may be better protected against bugs, and errors along with having extra performance.

“You don't have to squeeze out every last tiny bit of performance in your code and that also reduces a lot of friction for developing protocols.”

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Additional reporting by Andrew Fenton.

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