## Cross-Chain Interoperability Explained We can't move assets between blockchains directly, like two islands. We need a bridge! A bridge is a protocol that acts as a pathway between blockchains. ### Why We Need Bridges We need bridges for several reasons: * **Gas Fees:** We need to pay gas fees to process transactions on blockchains. * **Currency Conversion:** The currency needs to be converted for the appropriate chain. ### Bridging Terminology Here are some important terms related to bridging: * **Bridging:** The transfer of assets, like tokens, cross-chain. * **Cross-Chain Messaging:** The transfer of data cross-chain. ### How Bridges Work We'll look at two methods bridges use: * **Burn & Mint:** Tokens are burnt on the source chain, removed from circulation. The same number of tokens are then minted and given to the user on the destination chain. * **Lock & Unlock:** Tokens on the source chain are locked in a vault. A new, wrapped version of the token is then minted on the destination chain, and given to the user. ### Types of Bridges * **Native Bridges:** Built by the blockchain team. * **Third-Party Bridges:** Developed independently. These are often faster, but have higher fees. ### Security We also need to be aware of security risks. Because we don't need to wait for finality with third-party bridges, there is a possibility of a roll-back or reorg that could reverse our transaction. ### Auditing To ensure that the bridges we use are secure, we need to get them audited: * **Competitive Audit:** Placing the code on platforms like CodeHawks * **Private Audit:** Reaching out to a company like Cipher directly ### Cross-Chain Applications Vitalik Buterin, founder of Ethereum, stated the future is multi-chain, not cross-chain, due to security issues. He stated billions of dollars have been bridged across chains, but there is a need for applications to ensure security. We should ensure we audit applications before interacting with them!