When you look under the hood, bridges like Ronin’s typically work by locking up cryptocurrency in smart contracts on one chain, and then re-issuing those tokens in “wrapped” form on a destination chain. So for example, if you were to use the Ronin Bridge to move ether (ETH) from Ethereum to Ronin, ETH would get locked up on Ethereum to serve as 1:1 backing for wrapped ether (WETH) issued on Ronin.
Source: https://www.coindesk.com/layer2/2022/04/05/ronin-attack-shows-cross-chain-crypto-is-a-bridge-too-far/?utm_medium=referral&utm_source=rss&utm_campaign=headlines