Bridges

Bridges are mechanisms that connect two blockchains together, enabling interoperability between the two. This connection enables users to transfer data or digital assets across separate blockchains that may have different protocols, consensus mechanisms, and other underlying technologies.

Amendment draft XLS-38d introduces bridges to the XRP Ledger. To learn more about the specifics of the XRPL bridge implementation, see: XLS-38d-XChainBridge.

Bridge Governance

XLS-38d uses an XChainCreateBridge transaction to create a bridge by designating door accounts to manage the transfer of assets between blockchains. Door accounts are managed by a list of signers, requiring a specific quorum to approve transactions.

These specialized door accounts don't exist natively on EVM compatible blockchains, so Gnosis Safe is used as an alternate signer list system to manage bridge governance. Gnosis Safe uses smart contracts to manage multisig accounts; the smarts contracts are audited and used in other projects, such as Makr, ENS, and AAVE.

Before creating a bridge, you must create a Gnosis Safe account with a list of owners and a quorum threshold. You can then use the Gnosis account as a door account to manage assets, signers, and quorum.

Notes:

• The XRPL EVM sidechain offers a custom implementation of the Gnosis Safe management service. See: https://safe-evm-poa-sidechain.peersyst.tech/
• You can learn more about Gnosis Safe from their public documents. See: https://docs.safe.global/

XRPL EVM Sidechain Bridge Implementation

The XRPL EVM sidechain utilizes these components in its implementation of the bridge:

• Solidity smart contracts to implement the new transactions introduced by XLS-38d.
• Witness servers to sign attestations.
• A Bridge client UI to interact with the bridge.