1 Introduction

Since the introduction of Bitcoin, blockchain technology and the concept of decentralization have progressively gained popularity. Ethereum, with its smart contracts, opened the door to nearly limitless applications for distributed ledger technology. Early blockchain technology primarily addressed concerns related to security and decentralization, emphasizing the resolution of trust issues. As the demand for transaction processing capacity surged, Solana and other permissionless blockchains proposed solutions to scale processing performance to tens of thousands of TPS. Nevertheless, the current pivotal challenge lies in delivering an improved experience for users and developers, given the explosive growth of decentralized applications like Defi, GameFi, and NFTs. For instance, users must rely on the encryption method provided by each blockchain exclusively, and nothing will help if they happen to lose their private keys. Besides, DApps also cannot share transaction fees, even if they have significant contribution to the transaction volumes. This is not conducive to the formation of an ecosystem. The inflexibility in user operations and the fee mechanism are hindering the development of the decentralized economy.

Account abstraction solution of Ethereum community has alleviated the mentioned issues above to some extent, but not in a somewhat thorough, native manner. Additionally, there is currently a lack of fee-sharing mechanisms which are widely used within decentralized communities to attract applications and foster ecosystem economic alignment.

Flexibility of the blockchain need to be increased in order to address the issues. Therefore, we propose NERO, a next-generation modular blockchain featuring native abstract account mechanism, that is secure, scalable, and most importantly, flexible. NERO introduces a more structured and native mechanism for account abstraction, including integrated smart contracts, user operation pool, Paymaster, and more. This enables users to navigate the web3 world with the familiarity of web2 experiences. Additionally, NERO has devised a gas fee economics model that empowers DApps by sharing the gas fee according to the contribution, encouraging DApps to make every effort to optimize themselves. Moreover, NERO adopts a modular design to ensure high-performance transaction processing. The entire process is vertically divided into execution, settlement, and data availability. NERO employs a ZK Rollup-based Validium solution as its execution engine, along with a settlement chain fully compatible with EVM and Ethereum protocols, with consensus which supports large-scale node participation. And its data availability is based on data sampling validation schemes, which currently has the highest efficiency.

NERO is designed to collaborate with and support the development of dApps within its ecosystem. It establishes a novel foundation by leveraging a high-performance underlying permissionless blockchain, gradually adding flexibility enhancement in phases. NERO actively supports the development of Web 3.0 through innovative concepts, forming a permissionless blockchain with complete underlying capabilities that everyone can participate in. Compared with other permissionless blockchains, NERO is committed to making innovations and contributions in flexibility as well as transaction scaling, with the following 5 core technical features:

• Utilizing native account abstraction for a Web2-like user experience
• Blockspace 2.0: Implementing a multidimensional gas fee economy with transaction fee redistribution across the ecosystem dApps
• Adopting modular layered architecture, incorporating ZK Rollup and data availability solutions for high-performance transaction processing
• Employing a pipelined optimized BFT consensus mechanism, ensuring high throughput, decentralization, security, and fast transaction confirmation
• Ensuring full compatibility with Ethereum protocols and EVM, facilitating seamless application migration within the ecosystem