Preventing Cross-Chain Replay Attacks
Constructed unique domain separators per chain ID and incorporated monotonic nonces per user address, verified inside the destination smart contract before token minting.
Omnichain Asset Bridge
Two-Chain Trust-Minimized Asset Relayer & Bridge
Source codeThe engineering problem.
Cross-chain bridges are frequently targeted by replay attacks, relayer desynchronization, and front-running during gas price spikes.
Overview
The Omnichain Asset Bridge facilitates decentralized asset transfers between two EVM blockchain environments. It combines on-chain escrow contracts with an off-chain TypeScript relayer that listens for emission events, collects validator signatures, and delivers verifiable mint/unlock payloads to the destination network.
- EVM Chains
- 2
- Replay Protection
- 100%
- Confirmation Blocks
- 12
Decentralized Lock-and-Mint with Relayer Verification
The architecture decouples the locking mechanism on Source Chain from the minting mechanism on Destination Chain through an authenticated relayer daemon.
Architecture / Two-chain asset bridge
BridgeVault.sol: Escrows user tokens on Source Chain, emitting an indexed BridgeDeposit event with nonce, recipient, and amount.
Technical challenges & mitigations.
Relayer RPC Liveness & Network Reorgs
Implemented confirmation depth requirements (e.g. 12 block confirmations) before queuing payloads, coupled with SQLite WAL logging for crash-resilient message dispatch.
Key features.
- 01Two-way asset transfer between EVM testnets and local nodes
- 02EIP-712 typed data hashing for tamper-proof relayer signatures
- 03Gas-efficient batch verification algorithm
- 04Automated confirmation depth tracker with SQLite queue
Next study / 02