Stargate

In the long run, FVM will eventually be part of a broader family of blockchains. In such a scenario, bridges are necessary between FEVM and EVM chains. Stargate is a cross-chain interoperability protocol. It enables FEVM to be connected to other EVM chains. Stargate is a protocol for cross-chain messaging and interoperability for FEVM. Stargate can be used to send cross-chain messages between FEVM and other EVM chains. It can also be used for implementing cross-chain transactions, wherein Filecoin actors can send transactions that are fulfilled on another EVM chain. Smart contracts sitting on other chains benefit from accessing the storage capabilities of the Filecoin network. Similarly, Filecoin actors should be able to interact with code on other chains, or generate proofs of Filecoin state or events that can be understood by agents sitting on other chains. There are various use-cases and applications which subsequently arise, this includes token and NFT bridging, connecting liquidity across DEX's, cross-chain governance, metaverse interoperability and even chain-agnostic data DAOs. As an example, we demonstrate token bridging between the Goerli testnet and FEVM Hyperspace testnet using the Stargate bridge. We make use of a lock-and-mint mechanism for bridging tokens.

The project is built using solidity smart contracts, on Goerli and FEVM Hyperspace testnet. In order to prove the inclusion of messages, we maintain Merkle trees on either chains. They can be used to generate and verify proofs, for which we made use of the OpenZeppelin library. We built a relay agent to watch events on the source chain and relay messages to the destination chain. The example application was built using Next.js, TailwindCSS, wagmi and RainbowKit.