Bridging the Gap: How Cross-Chain Bridges Actually Work

Why Cross-Chain?

Users want to move assets between Ethereum, Polygon, Solana, etc. Bridges let you do this — but how?

Diagram: Asset Movement Across Chains

Bridge Architecture

Key Components

• Lock/Mint or Burn/Mint patterns
• Validators / Relayers
• Proof Verification (e.g. Merkle proofs)

Sample Bridge Contract

solidityCopy
contract EthereumBridge {
    mapping(bytes32 => bool) public processedProofs;

    function verifyAndMint(bytes32 txHash, address to, uint amount, bytes memory proof) external {
        require(!processedProofs[txHash]);
        require(verifyProof(txHash, proof), "Invalid proof");

        processedProofs[txHash] = true;
        _mint(to, amount);
    }
}

Tools to Explore

• LayerZero
• Axelar
• Wormhole

Security Notes

• Watch for bridge hacks (over $2B stolen in 2022)
• Favor audited, decentralized bridges