Gas Optimization Audit: Hyperliquid Bridge

Hyperliquid Bridge, a high-value, permissionless bridge that connects ERC-20, ERC-721 and custom token assets between Ethereum L1 and multiple L2 rollups, has undergone a gas optimization audit. The bridge's contract suite includes BridgeCore.sol, Verifier.sol, Governance.sol, TokenVault.sol, and Utils.sol with approximately 2,100 lines of Solidity code.

The audit focused on gas consumption of the most frequently called external entry points (deposit, withdraw, finalizeWithdrawal, claimRefund) and on gas-critical internal routines (proof verification, bitmap updates, batch processing).

The key findings reveal several gas inefficiencies that directly increase the bridge's operational costs and, consequently, user fees. These include unpacked struct fields causing unnecessary storage operations, loop-based batch processing that scales linearly with batch size, redundant external calls, hashing in proof verification, unchecked arithmetic operations, event emission with full byte payloads, and use of legacy libraries.

These issues collectively contribute to an average gas cost of approximately 210k on L1 and 85k on L2 per deposit/withdrawal, which is 30% higher than comparable bridges like Connext and Hop.

The gas inefficiencies can lead to economic risks, including user friction, potential relayer DoS attacks, and the possibility of partial state updates causing inconsistent accounting. While none of these vectors directly result in a loss of funds, they degrade the bridge's availability and increase operational costs. The overall risk score is 6 out of 10, indicating that while the bridge is functionally sound, gas-related issues are non-trivial and require immediate remediation.