L2 Bridging Mechanics
Bridges move assets between chains by locking tokens on the source chain and minting representations on the destination. The architecture varies dramatically: canonical bridges inherit rollup security but impose long withdrawal delays, liquidity networks use pre-funded pools for instant transfers, and lock-and-mint bridges rely on external validator sets. Each model makes different trust and speed tradeoffs.
🌉 Bridge Flow Visualization
Canonical Cost
$2.10
Fast Bridge Cost
$18.50
Liquidity Net Cost
$35.00
Fast Bridge Fee
0.05%
Amount Received
9.995 ETH
⚖️ Bridge Comparison
| Type | Speed | Fee | Trust | Examples |
|---|---|---|---|---|
| Canonical | 7 days (optimistic) | Gas only | Rollup security | Arbitrum Bridge, OP Bridge |
| Fast Bridge | 1-20 minutes | 0.04-0.1% | Relayer + rollup | Across, Connext |
| Liquidity Net | Seconds-minutes | 0.05-0.3% | LP solvency | Stargate, Synapse |
| Lock & Mint | 10-30 minutes | 0.05-0.2% | External validators | Wormhole, Multichain |
💀 Notable Bridge Hacks
Ronin — $625M
March 2022. Compromised 5/9 validator keys on the Ronin bridge (Axie Infinity). Social engineering + insider access.
Wormhole — $320M
February 2022. Signature verification bypass on Solana side. Attacker minted 120k wETH without depositing on Ethereum.
Nomad — $190M
August 2022. Faulty upgrade made every message provable. Hundreds of copycats drained the bridge in a chaotic free-for-all.
🛡️ Risk Radar
Canonical (Safest)
Inherits full rollup security. No external trust assumptions. Slow withdrawals are a feature, not a bug — the 7-day delay is the challenge window that keeps funds safe.
External Validators (Riskiest)
Trust assumptions outside the rollup. Validator key compromise = total fund loss. Bridges hold massive TVL, making them high-value targets for state-sponsored attackers.