Bonded Bridging and Capital Efficiency in Fast Cross-Chain Transfers
Summary
The paper presents Across Prime, a bonded design for fast cross-chain bridges. In conventional escrowed bridges, users pay into an origin-chain contract, and relayers advance their own funds on the destination chain while waiting for fulfillment verification. Across Prime instead lets a relayer receive the origin-chain payment immediately, with a security bond backing its uncompleted obligations. The bond can be reused once the destination action is complete, even if the settlement oracle takes longer to finalize.
The paper outlines a protocol using origin and destination contracts, cumulative payment tracking, and matching Merkle roots to track fills and limit simultaneous exposure. It also proposes adding a user’s funds to the bond when the existing deposit cannot cover a payment. A worked example compares capital throughput under stated block-time, bond-size, and oracle-delay assumptions. These are illustrative figures, not measured performance. The design still depends on correct fulfillment tracking, adequate collateral, and secure settlement; its claimed efficiency and security are not supported here by empirical evaluation.
Key ideas
- A relayer bond can secure payments made directly to the relayer on the origin chain.
- The bond becomes reusable after destination fulfillment, reducing dependence of capital use on oracle settlement time.
- Cumulative payment values and matching Merkle roots help track which intents have been fulfilled.
- The turnstile contract is designed to prevent simultaneous payments from exceeding the relayer’s available security.
- When a relayer’s bond is insufficient, adding the user’s funds can provide just-in-time collateral.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.