Two Ways to Move Crypto Between Chains, and the Line Between Them
Cross-chain swaps are not one thing. There are two distinct mechanisms people call a "crypto bridge," and the difference matters once real money is on the line. Pick the wrong one and you wait, pay, or get rekt. Pick the right one and the whole thing takes about two minutes.
Both solve the same problem: you have tokens on Chain A and want tokens on Chain B. A centralized exchange can do it if the pair exists, but that means depositing, trading, withdrawing, and trusting a custodian with your assets for the duration. A crypto bridge does it without handing custody to a middleman, and that's why the term exists at all.
Locked and minted: the custodial bridge
The first type locks your tokens in a smart contract on the source chain, then mints an equivalent wrapped token on the destination chain. Think of it as a collateralized IOU. You send 1 ETH to the bridge contract on Ethereum, and 1 wETH appears in your wallet on, say, Arbitrum. When you bridge back, the wrapped token is burned and the original is released. The locked assets back the wrapped ones 1:1, audited by the contract code rather than a company's promise.
The risk lives in the contract. If the lock-up contract has a bug, or its validator set gets compromised, the collateral backing every wrapped token in circulation can vanish. The Wormhole exploit in February 2022 drained roughly $320 million by forging signatures on the Solana side. The bridged tokens were still in the contract, but the wrapped versions on the other chain had effectively been counterfeited. That kind of failure is specific to this model.
Swapped and settled: the liquidity bridge
The second type uses liquidity pools on both ends. You deposit Token A on Chain A, and a relayer or smart contract releases Token B from a pool on Chain B. No minting, no wrapping, no 1:1 IOU. The bridge acts more like a forex desk: it holds reserves of common assets on multiple chains and matches deposits against them.
This design is faster, usually cheaper per transaction, and the worst-case failure is bounded by the pool's depth. Lose the pool and liquidity providers take the haircut, not every user with a wrapped balance. The trade-off is slippage on large transfers and dependence on the relayer staying online. If you're moving $200 of USDC, you won't notice either issue.
Where the line falls
The split comes down to whether wrapped tokens are created. Lock-and-mint bridges issue new assets that represent claims on locked ones. Liquidity bridges settle in the destination chain's native tokens, no claim required. The first is structural and capital-efficient for institutions moving eight figures. The second is friendlier for the person bridging $500 to use a dApp on a cheaper chain.
For a first move between two chains you control, a crypto bridge that routes through liquidity pools is the simpler path. Connect the source wallet, connect the destination, pick the asset, confirm. The wrapped-asset model is worth understanding before you trust it with anything you can't afford to lose, and it dominates where large, infrequent transfers justify the trust assumption.