ERC-6170: Cross-Chain Messaging Interface

A common smart contract interface for interacting with messaging protocols.

Metadata

Status: DraftStandards Track: ERCCreated: 2022-12-19

Authors

Links

GitHub page Discussion on Ethereum Magicians

Abstract

This EIP introduces a common interface for cross-chain arbitrary message bridges (AMBs) to send and receive a cross-chain message (state).

Motivation

Currently, cross-chain arbitrary message bridges lack standardization, resulting in complex competing implementations: Layerzero, Hyperlane, Axelar, Wormhole, Matic State Tunnel and others. Either chain native (or) seperate message bridge, the problem prevails. Adding a common standardized interface to the arbitrary message bridges provides these benefits:

Ease Of Development: A common standard interface would help developers build scalable cross-chain applications with ease.
Improved Scalability: Cross-chain applications can efficiently use multiple message bridges.
Improved Security: Confronting security to specific parameters. At present, every message bridge has its diverse security variable. E.g., In Layerzero, the nonce is used to prevent a replay attack, whereas Hyperlane uses the Merkle root hash.
Improved Robustness: Message bridges involving off-chain components are not censorship-resistant and are prone to downtimes. Hence, apps built on top of them have no choice but to migrate their entire state (which is highly impossible for large complex applications).

Specification

The keywords "MUST," "MUST NOT," "REQUIRED," "SHALL," "SHALL NOT," "SHOULD," "SHOULD NOT," "RECOMMENDED," "MAY," and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.

Every compliant cross-chain arbitrary message bridge must implement the following interface.

Rationale

The cross-chain arbitrary messaging interface will optimize the interoperability layer between blockchains with a feature-complete yet minimal interface. The light-weighted approach also provides arbitrary message bridges, and the freedom of innovating at the relayer level, to show their technical might.

The EIP will make blockchains more usable and scalable. It opens up the possibilities for building cross-chain applications by leveraging any two blockchains, not just those limited to Ethereum and compatible L2s. To put this into perspective, an easy-to-communicate mechanism will allow developers to build cross-chain applications across Ethereum and Solana, leveraging their unique advantages.

The interface also aims to reduce the risks of a single point of failure (SPOF) for applications/protocols, as they can continue operating by updating their AMB address.

Security Considerations

Fully permissionless messaging could be a security threat to the protocol. It is recommended that all the integrators review the implementation of messaging tunnels before integrating.

Without sender authentication, anyone could write arbitrary messages into the receiving smart contract.

This EIP focuses only on how the messages should be sent and received with a specific standard. But integrators can implement any authentication (or) message tunnel-specific operations inside the receive function leveraging data_ parameter.