# A Practical Example To further clarify the role of [[ZKP/ZKP Base Layer/Core Concepts/Zero-Knowledge Proofs|ZK]] wrappers, consider a practical example in the context of a decentralized [[ZKP/Data Marketplace/Intro|data marketplace:]] - **Process:** A [[ZKP/ZKP Base Layer/ZKP Blockchain/Storage Layer/Network Security Under Load/Circuit Design for AI Tasks|circuit]] defines a computation, such as verifying the validity of a dataset ([[Zero-Knowledge Proofs|e.g., "Does the dataset meet specific quality criteria?]]"). The proof is generated off-chain using Substrate's off-chain workers, ensuring that the dataset's contents remain private, and submitted to either an EVM verifier contract or a native Substrate pallet for validation. The verification process is lightweight and weight-efficient within Substrate's execution model, ensuring minimal impact on blockchain resources [9, 19]. - **Example Scenario:** In a [[ZKP/Data Marketplace/User Interactions/Interactions of Dataset Consumers|data trade scenario]], a seller uploads a dataset to the marketplace and generates a [[ZKP/Data Marketplace/Technical Basis/Cryptographic Foundations/Lifecycle of zk-SNARKs|zk-SNARK]] proof to confirm its validity (e.g., size, format, or quality metrics) without exposing the dataset itself. The buyer's smart contract (implemented in either EVM Solidity or native Substrate pallet) verifies the proof on-chain, confirming that the dataset meets the agreed-upon criteria. If the proof is valid, the transaction proceeds through Substrate's unified state management system, and the buyer gains access to the dataset via a content identifier (CID) stored on-chain. This ensures trust between parties without compromising data privacy, leveraging Substrate's cross-runtime communication capabilities and demonstrating a key advantage of ZK wrappers in decentralized marketplaces [36, 46]. See also: [[ZKP/ZKP Base Layer/ZKP Blockchain/Technical Build Application Layer/EVM Compatibility|EVM Compatibility]]