Ethereum’s rollups are ‘gold standard’ but Plasma needs a revisit: Buterin

November 15, 2023 Coin Telegraph

Vitalik Buterin called the early Ethereum scaling solution Plasma “underrated” and a “significant security upgrade” for chains that would otherwise be validiums.

Plasma, a once-prominent Ethereum layer 2 scaling solution, should be revisited by teams currently working on zero-knowledge Ethereum Virtual Machines (EVMs), says Ethereum co-founder Vitalik Buterin.

Invented in 2017, Plasma diverts data and computation — except deposits, withdrawals and Merkle roots — to an off-chain environment.

It was superseded by optimistic and zero-knowledge (ZK)-rollups as the two solutions offered cheaper client-side data storage costs and security properties that “cannot be matched,” Buterin explained in a Nov. 14 X (Twitter) post.

Exit games for EVM validiums: the return of Plasmahttps://t.co/QgyzXAl0wv
— vitalik.eth (@VitalikButerin) November 14, 2023

Buterin said rollups remain the “gold standard,” but Plasma is an “underrated design space” that shouldn’t be forgotten.

“Plasma can be a significant security upgrade for chains that would otherwise be validiums.” Buterin added.

“The fact that ZK-EVMs are finally coming to fruition this year makes it an excellent opportunity to re-explore this design space, and come up with even more effective constructions to simplify the developer experience and protect users' funds.”

Like Plasma, validums move data and computation off-chain but implement ZK-proofs to validate transactions. Plasma, on the other hand, uses fraud proofs — which are much slower.

Buterin argued improvements in ZK-proofs, such as validity proofs, address the past limitations of Plasma, making it more viable as a scaling solution.

Adapting Plasma for applications beyond payments has also proven to be an Achilles heel for Plasma before ZK-proofs entered the mainstream, Buterin acknowledged.

Buterin expects the Ethereum layer 2 ecosystem to evolve with diverse technological approaches.

Babe wake up Vitalik just revived Plasma
— sassal.eth (@sassal0x) November 14, 2023

Minimal Viable Plasma, Plasma Cash and Plasma Cashflow are among the iterations that have stemmed from Plasma.

Ethereum layer 2 scaling-focused firm Polygon Labs implemented Plasma in 2019 but has implemented several other solutions since.

The movement away from Plasma was partially attributed to Plasma Group, a nonprofit research firm announcing that they would cease working on Ethereum-based scalability in January 2020.

OMG, the token of OMG Network — which uses Plasma — spiked 28.6% to $0.78 in a three-hour window following Buterin’s post, according to CoinGecko. However, it has since fallen 14.3% to $0.67.

Magazine: ZK-rollups are ‘the endgame’ for scaling blockchains: Polygon Miden founder

Optimism network launches testnet fault-proof system in pursuit of decentralization

October 3, 2023 Coin Telegraph

Coin Telegraph

OP Labs implemented its modular fault-proof system on the OP Goerli testnet.

OP Labs, the developer of the Optimism network, launched a testnet version of its fault-proof system, according to an Oct. 3 blog post. Once it completes testing, it will allow for “a more decentralized and efficient Superchain,” the post stated. The new system is currently deployed to the Optimism Goerli network.

*Optimism Goerli block explorer. Source: Etherscan*

Currently, OP Stack-based networks use centralized sequencers to bundle transactions and submit them to Ethereum. Users cannot submit fraud proofs to block the sequencer if it submits incorrect data, creating the possibility of fraudulent transactions being confirmed if an attacker can control it. L2Beat has warned of this risk in its report on Optimism, stating, “users need to trust block Proposer to submit correct L1 state roots.”

OP Stack-based networks like Optimism and Base are intended to be optimistic rollups — a type of layer 2 that relies on Ethereum for its security. In a January 2021 essay, Ethereum co-founder Vitalik Buterin argued that optimistic rollups must allow users to submit fraud proofs to block fraudulent withdrawals to Ethereum. Otherwise, they’re not truly decentralized.

In November 2022, Buterin claimed that some rollups could have “training wheels” that keep them temporarily centralized while they work on a fraud-proof system but argued that they should work toward decentralization.

OP Labs claims the new fault-proof system will help fulfill the goal of decentralization for OP Stack networks: “The system is designed to eventually enable secure bridging without central fallback.”

In addition, it claimed the new system is modular, allowing each network to develop its own system for preventing fraud. It consists of three separate components: a fault-proof program (FPP), a fault-proof virtual machine (FPVM) and a “dispute game protocol.” Because these three components can be implemented separately, it opens up the possibility for each network to “custom-build a fault proof system.”

According to the post, this will create more diversity in the Optimism Superchain, ultimately making the whole ecosystem more secure. A network could even decide to use zero-knowledge proofs (ZK-proofs) as a type of fraud-proof, the team stated. ZK-proofs are generally utilized in zero-knowledge rollups, but not Optimistic ones.

OP Labs has been trying to build an interconnected web of blockchain networks called the “Superchain.” To accomplish this, it created the OP Stack, a set of software tools that can be used to create custom blockchain networks. Avail network has created “OpEVM” software designed to accomplish the same objective while using Avail as the base layer instead of Ethereum. Polygon’s ZK Supernets and zero-knowledge Ethereum Virtual Machine Hyperchain are other examples of Superchain competitors.

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

September 11, 2023 Coin Telegraph

Arbitrum One

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.

Both Arbitrum and Optimism operate as optimistic rollups!

However, Optimism and Arbitrum differ in their approaches to fraud-proof mechanisms.

Arbitrum: multi-round → longer confirmation times, more secure
Optimism: single-round → faster

4/ pic.twitter.com/mp0Nj86Fxz
— The Smart Ape (@the_smart_ape) September 1, 2023

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.”

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

After months in dev, we’re announcing BOLD (Bounded Liquidity Delay), a new dispute protocol that enables permissionless validation for Arbitrum chains, potentially removing the need for permissioned validation, dramatically improving decentralization. https://t.co/SHegVRGqXf
— Offchain Labs (@OffchainLabs) August 3, 2023

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.

Magazine: DeFi Dad, Hall of Flame: Ethereum is ‘woefully undervalued’ but growing more powerful

Fraud Proofs