Optimism and ZK Roll-ups are both scaling solutions for Ethereum, but they have different approaches to solving the scalability problem:
Optimism: Optimism is a layer 2 scaling solution for Ethereum that uses a combination of optimistic virtual execution and fraud proofs to allow for faster and cheaper transactions. It works by moving some of the transactions off the main Ethereum blockchain and into a separate layer where they can be processed more efficiently. The result is a faster and cheaper user experience while still maintaining the security of the Ethereum blockchain.
ZK Roll-ups: ZK Roll-ups, on the other hand, use zk-SNARKs (Zero-Knowledge Succinct Non-Interactive Argument of Knowledge) to batch multiple transactions into a single transaction, which is then confirmed on the Ethereum blockchain. This results in reduced transaction costs and increased scalability, as many transactions can be processed in a single confirmation. However, the trade-off is that ZK Roll-ups require a more complex setup and a deeper understanding of zk-SNARKs technology.
In summary, Optimism is a layer 2 scaling solution that offers faster and cheaper transactions while maintaining the security of the Ethereum blockchain. ZK Roll-ups, on the other hand, offer improved scalability by batching transactions and reducing costs, but at the cost of added complexity and a deeper understanding of zk-SNARKs technology.