Cross-Chain Bridges & Risks

At a Glance

Bridges let DeFi users move collateral across chains, but they introduce smart contract and liquidity risks. You'll learn safer bridging practices and design differences.

Lock-and-MintLiquidity NetworksAttack VectorsSafety Checklist

Who Is This For?

•DeFi users active on multiple chains or rollups
•Traders moving collateral for better yields or fees

Learning Objectives

01Describe lock-and-mint vs liquidity network bridges
02Identify main attack vectors on bridges
03Follow a checklist for safer cross-chain transfers

Section 1

Why Bridge?

DeFi doesn't live on one chain. The best yields, cheapest fees, and most active protocols are spread across ecosystems.

💸

Cheaper Transactions

Ethereum L1 gas can cost $5-50+ per transaction. L2s like Arbitrum and Base offer the same DeFi protocols for pennies. Bridging unlocks massive gas savings.

🎯

Access Opportunities

Unique protocols, incentive programs, and yield farms often launch on specific chains. GMX on Arbitrum, Aerodrome on Base, Jupiter on Solana — bridging gets you there.

⚡

Position Collateral

Need to add margin to a perps position on dYdX? Rebalance LP on Arbitrum? Your collateral needs to be where the action is.

Bridge Route Planner

Select your route and priority to get a recommendation:

From Chain

To Chain

Priority

→ Canonical Bridge

Low Risk · 10-15 min deposit

Official Arbitrum Bridge

Safest option. L1 security guarantees. Deposits are fast (10-15 min).

Section 2

Bridge Designs & Risks

Each bridge type makes different tradeoffs between speed, security, and token format. Know what you're using.

Compare Bridge Designs

🔒

Lock-and-Mint

Your tokens are locked in a smart contract on the source chain. Validators confirm the deposit, and equivalent wrapped tokens are minted on the destination chain. To return, you burn wrapped tokens and the originals unlock.

How It Works:

Lock tokens

Smart contract holds your ETH on Ethereum

Validators confirm

Bridge validators attest to the deposit

Mint wrapped

wETH minted on destination chain

Speed

Slow to Medium (10-60 min)

Trust Model

Validator set / Multisig

You Receive

Wrapped (e.g., WETH, wUSDC)

Best For

Moving assets to chains without native liquidity

Key Risk:

If the lock contract is exploited, wrapped tokens become worthless — they're no longer backed 1:1. The Wormhole hack ($320M) was exactly this.

DeFi Note:

Wrapped tokens may not be accepted as collateral everywhere. Check if your destination protocol accepts wETH vs native ETH.

WormholePortalPolygon PoS BridgeMultichain (defunct)

Attack Vector Explorer

Bridges are crypto's most exploited infrastructure. Over $2.5B has been stolen from bridge hacks.

🔑

Validator / Multisig Compromise

critical

Attackers gain control of enough validator keys or multisig signers to authorize fraudulent withdrawals. They mint unbacked tokens or drain the locked pool.

Real Example:

Ronin Bridge — $625M (March 2022)

Social engineering, phishing, or operational security failures compromise private keys. If a bridge uses 5-of-9 multisig and 5 keys are compromised, the attacker controls the bridge.

How to Protect Yourself:

Prefer bridges with decentralized validator sets (not small multisigs). Check how many signers are required and who they are.

Potential Loss: All locked funds

Section 3

Safety Steps

A repeatable process for every bridge transfer — from choosing a route to confirming arrival.

The 5-Step Bridge Process

1. Choose Your Route

Decide which chain you need funds on and why. Different DeFi protocols live on different chains — check where the opportunity is.

Tip: Match the bridge to your priority: canonical for safety, liquidity network for speed, aggregator for best price.

Step 1 of 5

Pre-Bridge Safety Checklist

Check off each item before confirming a bridge transaction:

🔗Verified official bridge URL (bookmarked, not from search)critical

🧪Sent a small test transaction firstcritical

⛽Have native gas token on destination chainhigh

📡Checked bridge and network status pageshigh

🔧No bridge upgrades or maintenance in progresshigh

📋Verified contract address matches official docscritical

🎁Understand if receiving native or wrapped tokensmedium

📊Transfer amount is appropriate (not entire portfolio)high

Safety Score:0/8 Not safe — complete critical items

Watch Out

Common Mistakes & Gotchas

🎣

I Googled 'Stargate bridge' and clicked the first result

Phishing sites bid on Google Ads for bridge keywords. Always bookmark official URLs from the protocol's verified Twitter or docs. Navigate directly — never from search.

🚦

Network is congested but I need to bridge now for this yield opportunity

Bridging during congestion leads to stuck transactions, failed transfers, and wasted gas. If the yield opportunity requires rushed bridging, it's probably not worth the risk.

⛽

I bridged 50 ETH to Arbitrum — I'll figure out gas later

Without ARB or ETH for gas on the destination chain, your 50 ETH is stranded. Always ensure you have native gas tokens on both sides before bridging.

🎁

I got wETH.e from the bridge — that's the same as ETH everywhere

Wrapped bridge tokens vary by bridge. Aave on Arbitrum accepts WETH but maybe not wETH.e from a specific bridge. Always check which token version your DeFi protocol requires.

Golden Rule: When in doubt, use the canonical bridge. It's slower, but it carries no trust assumptions beyond the chain itself. Speed is a luxury — security is a necessity.

Test Yourself