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Introduction

ERC-7786 is a proposed standard that defines an interface for contracts to send and receive cross-chain messages. It aims to improve composability and interoperability among the various cross-chain messaging protocols. Instead of developing applications against the proprietary and isolated interface of a single protocol, ERC-7786 allows app developers to use a common framework, minimizing lock-in to specific vendors or technologies. If needed, protocol-specific features can remain available under this common framework through non-standard attributes, without breaking interoperability of the core functionality of simple cross-chain messaging. Messaging protocols that do not natively implement this standard can be brought into the framework via adapters, ensuring broad compatibility.

Key Features

  1. Universal Interface: Smart contracts can use a single interface for cross-chain messaging, reducing vendor lock-in and improving portability.
  2. Extensibility: Protocol-specific features can be implemented as attributes, making the standard flexible while maintaining a shared core of functionality.
  3. Compatibility Beyond EVM: ERC-7786 is designed to work with chains outside of Ethereum and EVM ecosystems, fostering broader adoption.
  4. Post-Processing Support: Some protocols require additional parameters or actions to complete message delivery. ERC-7786 accommodates these requirements via post-processing or attributes.
  5. Secure Message Handling: The standard ensures that cross-chain messages are verified and processed securely, protecting assets and permissions.

How It Works

  • Sending Messages: A SourceGateway contract allows a sender to specify the destination chain, receiver address, message payload, and optional attributes. The gateway processes the request and emits a MessagePosted event.
  • Receiving Messages: A DestinationGateway validates the message using the cross-chain protocol and delivers it to the receiver contract via the executeMessage function.
  • Attributes: Attributes enable advanced functionality such as setting gas limits, passing metadata, or handling protocol-specific requirements.

Example Use Cases

  1. Cross-Chain Token Transfers: Transfer tokens across blockchains while including metadata, such as gas fees or payment conditions, in a decentralized manner.
  2. Cross-Chain Governance: Execute governance decisions across multiple chains by sending proposals or votes from one chain to another.
  3. Cross-Chain NFT Actions: Enable users to mint or transfer NFTs on one chain while reflecting changes on another.

ERC-7786 is currently in the draft stage, and the community is actively discussing enhancements to attributes, payload structures, and metadata handling. By standardizing cross-chain messaging, ERC-7786 opens the door for a new class of cross-chain native applications while reducing the complexities and risks associated with proprietary implementations.