Darwinia Msgport Use Case: Helix xToken Bridge

Helix Bridge is a fully open-source and decentralized cross-chain asset bridge using Darwinia Msgport as its cross-chain messaging service provider.

xToken Bridge

Helix Bridge offers a cross-chain mapping token service, which is built on a cross-chain token backing-issuing protocol based on the Cryptocurrency Backed Asset (CBA) model. This model ensures that tokens transferred across different blockchain networks are backed by equivalent cryptocurrency assets on the source chain.

The xToken protocol is currently less used because the business requires custody of users’ assets. This may be more vulnerable to hackers than the LN bridge.

When does cross-chain occur?

Currently, there are two places that are using the cross-chain messaging service of Darwinia Msgport. All two steps involve cross-chain messages that contain a proof to prove that something has happened on another chain.

Mapped Token Insurance

After completing asset registration, users can lock their original tokens into the Backing module on the source chain. Once the message to prove this locking action was sent to the target chain, the Issuing module mints an equivalent amount of the mapped token into the user-specified account.

contracts/helix-contract/contracts/mapping-token/v3/base/xTokenBacking.sol at…

Original Token Redeem

The mapped tokens on the target chain can initiate a burn process. The Message Relayer then transmits this burn message to the source chain. Subsequently, the Backing module releases or unlocks the original token into the user’s account.

contracts/helix-contract/contracts/mapping-token/v3/base/xTokenIssuing.sol at…

Summary

While xToken Bridge is less commonly used in Helix products, it offers a robust token cross-chain transfer functionality. Leveraging Darwinia Msgport and the Cryptocurrency Backed Asset (CBA) model, Helix xToken Bridge has implemented a transparent cross-chain issuance and burning logic for mapped tokens.

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