Optimistic Rollup is one of several types of Rollup solutions in the blockchain space, each with its own unique characteristics and trade-offs. Here, I'll explain the key differences between Optimistic Rollup and other Rollup solutions
Arbitrum
Arbitrum is an Optimistic roll-up technology much like Optimism. It’s believed that Arbitrum fine-tuned the source code of Optimism to form a distinct layer 2 network.
The main difference between optimism and Arbitrum is the way they handle fraud-proofs. Optimism uses a single round fraud-proof, while Arbitrum uses multiple round fraud-proof. With single-round fraud-proof, optimism carries out instant verification as it relies on Layer 1 to complete the transaction. So, this approach completes transactions quickly, but the consequence is a high gas fee. While multiple round fraud-proof takes time with validation during transactions but this helps reduce gas costs. Optimism is “only” EVM-compatible while Arbitrum uses an Arbitrum Virtual Machine, Optimism has a Solidity compiler while Arbitrum supports all EVM programming languages.
Polygon
Polygon is one of those scaling solutions referred to as sidechains. It is a Defi scaling solution. And unlike Optimism which relies on Ethereum’s Layer 1 for transaction security, this scaling solution runs parallel to Layer 1 and has a built-in security framework.
Polygon makes use of the same virtual machine Ethereum uses, so it’s easy to outsource smart contracts to Polygon. Polygon uses Matic tokens to secure its network and pay transaction fees, so users will have to exchange Ether for the protocol’s native MATIC Token.
zkSync
zkSync is a type of ZK-Rollup. “zk” stands for zero-knowledge, which means that one party can prove to another party that it possesses certain information (in this case, transaction details) without revealing the details. To confirm the validity, each transaction is moved to an off-chain prover which generates a cryptographic proof called ZK-SNARK. SNARK stands for Succinct Non-Interactive Argument of Knowledge. The proof generated is thereafter posted on Layer 1.
Optimism and zkSync are closely related but the zkSync method of validating transactions can be somewhat complex. It ensures a higher throughput and lower cost without giving up security. On the downside, ZkSync is not an ideal model for building DApps and the different ZK-Rollup apps cannot interact with themselves on Layer 2.
Generally, the difference between Optimism and All Other ZK-rollups are as follows:
Security Model: The fundamental difference between Optimistic Rollup and ZK-Rollup is the security model. Optimistic Rollup assumes most transactions are valid, and disputes are resolved on-chain. In contrast, ZK-Rollup provides a more secure approach, where cryptographic proofs ensure the validity of all transactions without relying on an off-chain dispute resolution process.
Transaction Finality: ZK-Rollup typically offers faster transaction finality because there's no need for a dispute resolution phase, as is the case with Optimistic Rollup.
Data Availability: ZK-Rollup's use of cryptographic proofs can make it more storage-efficient, as it doesn't rely on storing all transaction data on the Ethereum mainnet.
Use Cases: Optimistic Rollup may be well-suited for applications that require compatibility with the EVM and can tolerate some trade-offs in terms of security and transaction finality. ZK-Rollup is often chosen for applications where security is a paramount concern, and faster transaction finality is desirable.
It's important to note that both Optimistic Rollup and ZK-Rollup have their own advantages and use cases. The choice between them depends on the specific requirements and trade-offs that best suit the applications and projects being developed on these Layer 2 scaling solutions.
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