Crypto Bridges explained
Bridges are fundamental pieces in the crypto puzzle: they are the key to interoperability, as they allow tokens to travel from one chain to another.
The word “bridge” is an unfit metaphor; it certainly does not define how bridges work in crypto. Tokens do not seamlessly travel from one end of a bridge to the other. Instead, when a token transfer is performed through a bridge, the token gets locked in a smart contract on the blockchain of origin, and a synthetic version of that token is minted and transferred on the other side. The word “wrapped” is usually used to define the synthetic version on the other side of the bridge because what you get when a token crosses a bridge is some encapsulated version of the original token that can circulate in the new blockchain.
For example, to transfer your ETH to the Polygon network, you’d lock ETH in Polygon’s PoS bridge and receive wETH on your Polygon address on the other side.
This creates a vector for hacks: bridges end up in the custody of massive amounts of funds and become an attractive single point of failure for hackers. Many of the most notorious hacks in crypto have targeted bridges. Three of the top five hacks, according to Rekt, have involved bridges.
Crypto bridges are as critical as they are risky. Interoperability is a core feature of Decentralized Finance, and there are many innovations taking place.
