The significance of ERC-7786 lies not only in making cross-chain interactions more convenient but also in its attempt to establish a unified standard for 'multi-chain collaboration' to combat 'entropy increase' at its core. This not only further promotes a 'unified' program for on-chain liquidity but also drives the multi-chain ecosystem towards maturity. (Background: Securing Ethereum EIP-7702 upgrade: a safe EOA to smart wallet transition proxy model) (Supplementary background: Human struggles that code cannot solve: internal strife, exodus, and future within the Ethereum core circle). The Ethereum ecosystem may soon transition from the chaotic phase of L2 'Warring States' into a unified era. The key to this lies in the ongoing ERC-7786, which attempts to set a universal cross-chain communication 'interface standard' for Ethereum, thereby integrating various messaging standards under a unified API to enable communication between smart contracts across different blockchain networks within the Ethereum ecosystem. As early as April 15, Ethereum Foundation member joshrudolf.eth publicly emphasized that 'cross-chain messaging is one of the key elements in solving the cross-chain user experience problems of Ethereum.' So what exactly is ERC-7786, what problems does it aim to solve, and why is it important? This article will help you understand this new standard that all Ethereum users should pay attention to. 01 Ethereum needs a unified cross-chain communication protocol. As is well known, from the initial multi-chain concept of Cosmos and Polkadot to the prosperity of Rollup in the Ethereum L2 era, especially with the significant development of application chains such as OP Stack, Arbitrum Nova, and Starknet, liquidity has become increasingly fragmented across Ethereum and L2. According to L2BEAT's incomplete statistics, there are more than a hundred Ethereum L2s in a broad sense, leading to a long-discussed issue - the extreme fragmentation of liquidity. It is worth noting that even though they are all based on the Ethereum ecosystem, different L2s do not communicate with each other. Users wishing to transfer assets from Arbitrum to Starknet or interact with contracts across different L2s can only rely on cross-chain bridges or cross-chain messaging protocols to achieve safe interactions between contracts, users, and assets across multiple networks. Source: L2BEAT This not only results in users incurring friction costs annually due to cross-chain barriers but more critically, the synergistic effects between different L2s within the Ethereum ecosystem have also been severely weakened. Although there are already several protocols that have implemented inter-chain communication functions, each protocol has its own interface, calling methods, and security models. Developers find it nearly impossible to reuse code or interface logic across different protocols, which directly leads to each party repeatedly 'reinventing the wheel' and high operational costs, with the user experience being extremely fragmented. Therefore, the proposal of ERC-7786 is aimed at breaking this fragmented ecology by providing a unified standard interface for all inter-chain communication protocols, allowing DApps to communicate securely with any chain through the same 'gateway' without binding to a specific protocol: This standard is led by OpenZeppelin and supported by multiple cross-chain and modular projects including the Ethereum Foundation and Axelar, aiming to standardize a universal interface for decentralized applications (DApps) to safely send and receive messages across multiple blockchains. Source: erc7786.org 02 ERC-7786: Cross-chain communication 'unified interface' If we summarize ERC-7786 in one sentence, it is like the 'ERC-20' of the cross-chain communication field. Just as ERC-20 provides a standard interface for tokens and ERC-721 defines a general specification for NFTs, ERC-7786 also attempts to establish a unified, general 'communication interface' for cross-chain messaging - you can liken it to the 'USB standard' in the Web3 world, allowing any protocol to plug and play as long as it connects to the standardized interface. The following diagram presents the core components and processes of ERC-7786, demonstrating how to send and receive messages across different blockchains through standardized interfaces, where one ERC-7786 message includes four basic elements: Sender: identified in CAIP-10 format (e.g., eip155:1:0xabc...) Receiver: also identified as a CAIP-10 target address Payload: any executable data (bytes) Attributes: additional parameters, such as gas limits, processing priority, etc., expressed in function signature form (e.g., minGasLimit (uint256)) Source: erc7786.org Among them, sendMessage() is used to initiate messages from chain A, and executeMessage() is used for chain B to receive and execute. This 'send-receive closed loop' constitutes the foundational logic of cross-chain communication, allowing DApps to package the standard interface once and be compatible with multiple cross-chain protocol modules, achieving true 'protocol decoupling + communication freedom'. Currently, ERC-7786 has also announced that its interface functionality is complete and is awaiting the final merging of the binary interoperability address specification (i.e., unified address encoding). In the future, there are plans to add a 'Gas sponsorship' extension package that allows users to have third parties prepay gas when executing transactions on the target chain, thereby optimizing the user experience of inter-chain interactions. More critically, the design of ERC-7786 supports modular adaptation, allowing developers to build Adapters for existing mainstream cross-chain protocols (such as Axelar, LayerZero, Wormhole, etc.) without needing to restructure logic, enabling rapid compatibility with the ERC-7786 standard interface. This means that even if users, liquidity, and applications are distributed across multiple L2s or heterogeneous chains, DApps can utilize ERC-7786 to construct native cross-chain calling capabilities without being tied to specific bridge protocols or relying on cumbersome UI switches, significantly enhancing the overall experience and reducing integration complexity. It is worth mentioning that the attribute mechanism (Attributes) of ERC-7786 also allows the integration of extension functionalities from different cross-chain protocols, such as validation logic, state proofs, quota control, etc., without affecting the standard main process, thus leaving ample flexible interface space for the evolution of middleware and validation mechanisms. From this perspective, the significance of ERC-7786 goes beyond merely 'being compatible with multiple cross-chain protocols'; it also represents a new era in which the multi-chain architecture of Web3 is moving from 'cross-chain deployment' to 'native interoperability'. 03 What can ERC-7786 bring? For this reason, ERC-7786 is widely regarded as an important infrastructure driving Ethereum and the multi-chain ecosystem towards higher interoperability, breaking down long-standing protocol barriers and laying a unified standard infrastructure for future cross-chain functionality expansion, validation mechanism upgrades, and multi-chain collaboration. From a practical implementation perspective, the value brought by ERC-7786 can be summarized into two core beneficiaries - developers and end-users: For developers, they only need to open...

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