June Blockchain Technology Update: OP_RETURN Limit Increased to 4 MB, Discuss EIP-7782 Halves Ethereum Block Time, Solana Asynchronous Execution

Written by: GaryMa, Wu Blockchain

The WuBlockchain summarizes key developments in the blockchain technology space for June:

Bitcoin

● The Bitcoin Core development team announced that the Core 30 version, set for release in October, will modify the default OP_RETURN settings, increasing the data carrier limit from 80 bytes to nearly 4 MB. This decision marks a milestone victory for reformists led by Antoine Poinsot in their ongoing debate with conservatives like Luke Dashjr.

● Bitcoin developer Peter Todd is developing a mechanism to enable Bitcoin Core nodes to automatically disconnect from nodes launching “sweeper” attacks against his Libre Relay software. Previously, Todd advocated raising the Bitcoin Core default OP_RETURN limit to nearly 4 MB, sparking controversy. Opponents used “sweeper” software to mimic nodes and disrupt the propagation of large data transactions. The new rules are planned for the Core v30 release in October, with Todd intensifying countermeasures to defend his on-chain data expansion proposal.

● BitVM founder Robin Linus shared details on the BitVM3 protocol, which uses optimistic computation and garbled circuit technology to reduce the on-chain footprint of SNARK proof verification from 2–4 MB in BitVM2 to 56 kB (assertTx) and 200 bytes (disproveTx), achieving over 1,000x efficiency improvement. Introduced by Linus in 2023, BitVM aims to bring complex computations and smart contract functionality to Bitcoin through optimistic computation, where calculations are performed off-chain and verified on-chain only in case of disputes. Linus also leads the BitVM Alliance, including members like Fiamma, Zerosync, Element Labs, and Citrea.

Ethereum

● The Fusaka upgrade’s consensus layer (CL) specifications have been “frozen,” with execution layer specifications to be finalized at the next ACD meeting, preparing for Devnet 3 launch.

● Ethereum developer @Arvolear proposed the Confidential Wrapped Ethereum (cWETH) concept to enhance user privacy through application-layer technology. Using EC Twisted ElGamal commitment schemes and zk-SNARKs to encrypt balances and transfer amounts, cWETH supports anonymous P2P payments, donations, and transactions without relying on centralized entities. The cWETH draft is open for community feedback, with plans to develop it into a formal EIP standard.

● Ethereum core developer Barnabé Monnot discussed EIP-7782, which proposes reducing block generation time from 12 seconds to 6 seconds, planned for inclusion in the Glamsterdam upgrade by late 2026. Technical adjustments include compressing block proposal time from 4 seconds to 3 seconds and validation time from 4 seconds to 1.5 seconds, saving 6 seconds of latency. The proposal is in early discussion and requires rigorous testing to avoid smart contract compatibility issues.

● Nethermind’s Anshu Jalan and Lin Oshitani proposed a Blob sharing protocol based on EIP-7702 to address low Blob fill rates in Based Rollups (e.g., Taiko, with 7%-55% fill rates). Unlike Rollups with centralized sequencers that batch transactions for efficient Blob usage, Based Rollups face efficiency bottlenecks due to non-delayed publishing. The Blob sharing protocol aggregates data from multiple Rollups via L1 proposers, optimizing Blob usage and reducing costs for diverse Rollup ecosystems.

Ethereum L2s

● Taiko announced the launch of Based Preconfirmation on its Hekla testnet, enabling configurable block times targeting 2 seconds, with potential for further reduction. Currently, it operates with whitelisted sequencers, supported by three open-source clients: Nethermind, Chainbound, and Gattaca.

● Polygon released its “Gigagas” scaling roadmap, aiming to expand network capacity to 100,000 TPS to support global payments and real-world asset (RWA) on-chain applications. Short-term goals (by July 2025) include the Bhilai upgrade for 1,000 TPS, reducing finality to ~5 seconds and stabilizing gas fees. By year-end, Polygon targets 5,000 TPS, integrating Agglayer for cross-chain liquidity and introducing single-block finality to eliminate reorg risks. Long-term, enhanced validation architecture and Agglayer connections aim for 100,000 TPS to support large-scale institutional transactions and payments.

● ZKsync unveiled Airbender, claimed to be the “world’s fastest open-source RISC-V zkVM,” achieving ~21.8 MHz base proving speed on a single H100 GPU, nearly 6x faster than the second-fastest system. Integrated into ZKsync chains like Era, Abstract, and Sophon, Airbender reduces single-transfer costs to $0.0001. It enables Ethereum block end-to-end proving in 35 seconds and is fully open-source, supporting use cases like gaming, identity, and AI.

Solana

● Anza’s Andrew Fitzgerald submitted SIMD-0290 (Relax Fee Payer Constraint), proposing to relax handling of invalid fee payers. Current rules reject entire blocks due to invalid fee payers, but the new proposal allows such transactions to be included without execution, enabling asynchronous verification/execution and reducing processing costs. The proposal balances efficiency and security risks, ensuring backward compatibility, but requires addressing community concerns about CUs computation and potential attacks.

● Anza’s chief economist Max Resnick submitted SIMD-0301 (Asynchronous Execution), introducing asynchronous execution to eliminate replay bottlenecks in the consensus critical path (where validators re-execute block transactions). Unlike synchronous execution, where validators wait for transaction replays before voting, SIMD-0301 allows voting before block execution, reducing confirmation latency under the Alpenglow consensus and supporting multi-leader concurrency (MCL) and pipelined consensus. The proposal, still in draft, requires multiple prerequisites and is planned for activation post-Alpenglow consensus implementation.

● The Solana Foundation disclosed a second zero-knowledge proof vulnerability in the ZK ElGamal Proof native program. Reported by suneal_eth on June 10, the vulnerability allowed forging private transfer proofs. On June 11, the engineering team disabled Confidential Transfers via a multisig upgrade to the Token-2022 program. Validators were urged to upgrade to Agave/Jito-Solana v2.2.16 or Firedancer v0.505.20216, activating a feature switch at mainnet epoch 805 (June 19, 06:00 UTC) to fully disable ZK ElGamal pending a comprehensive audit. No funds were lost, as private transfers were not widely used. This follows a prior ZK ElGamal vulnerability on April 16 (fixed in v2.1.21/v2.2.11) due to a Fiat-Shamir hash field omission. Re-enabling private transfers will take months, pending audit and governance approval. Regular SPL tokens and transactions remain unaffected.

BNB Chain

● BNB Chain implemented the Maxwell upgrade on June 30, reducing BSC block time from 1.5 seconds to 0.75 seconds to enhance transaction confirmation speed and network responsiveness. The upgrade includes three proposals: BEP-524 (shorter block intervals), BEP-563 (improved validator communication), and BEP-564 (optimized block sync). Consensus parameters were adjusted, increasing Epoch length from 500 to 1,000 and TurnLength from 8 to 16 blocks, achieving ~1.875-second fast finality.

Aptos

● Aptos Labs announced a collaboration with Tsinghua University’s Wingtecher Labs to develop a cutting-edge testing tool for consensus algorithms. Combining automated testing, protocol state space exploration, and logic error detection, the tool aims to ensure the stability and security of Aptos’ next-generation Raptr consensus protocol. The project is expected to complete by Q2 2026, with the first integration phase already live for experimental testing.

● Aptos Labs and Jump Crypto launched Shelby, a decentralized hot storage network for high-performance Web3 applications like streaming, AI, social, and DePIN. Shelby’s Devnet is slated for Q4 2025, supporting Aptos, Ethereum, Solana, and other ecosystems.

Others

● Berachain announced its “Bectra” hard fork, becoming the first non-Ethereum chain to fully implement Ethereum’s Pectra execution layer features. The upgrade enhances tools for over 100 on-chain applications, improving user and developer interactions. Features include smart account functionality for wallets, batch transactions, spending limits, HONEY stablecoin gas payments, and recurring payments. While not adopting Pectra’s consensus layer changes, EVM compatibility ensures over 200 existing apps require no contract rewrites.

● Filecoin introduced FilCDN, a high-performance CDN by Space Meridian optimized for Filecoin data retrieval, accelerating content delivery and simplifying decentralized app development. FilCDN uses PDP (Proof of Data Possession) transactions for hot data retrieval, addressing compliance issues from high egress costs, improving retrieval compliance by 20x. Developers can leverage FilCDN via the Modular Worlds hackathon, while Checker Network and Filecoin Spark continue supporting network transparency.

● Kaspersky discovered SparkKitty, a new virus targeting iOS and Android crypto apps, stealing mnemonic phrase screenshots from user photo albums. Affected apps include “币 coin” on the App Store and SOEX (over 10,000 downloads) on Google Play. Linked to the earlier SparkCat virus, SparkKitty has been active since early 2024, primarily targeting Southeast Asia and China.

● Privacy Pools, backed by Ethereum co-founder Vitalik Buterin, added stablecoin support, allowing anonymous transfers of USDT, USDC, and DAI via zero-knowledge proofs for cash-like privacy transactions. Using Vitalik’s 2023 “association set provider” mixing scheme, it ensures privacy while filtering illicit funds.

● Decentralized prover network Succinct launched Stage 2.5, the final phase of its Prover Network testnet, introducing top-tier zero-knowledge proof hardware teams to build the world’s largest proving cluster. Stage 2.5 supports competitive auctions, Sybil-resistant staking, and high-throughput settlement, enabling anyone to run proving nodes. The testnet will airdrop PROVE tokens to incentivize staking, preparing for mainnet launch.

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