Smart contracts are good at executing rules but not good at handling large files—this is a common challenge for blockchain developers. Walrus has come up with a solution: have contracts reference verifiable data blocks instead of piling everything onto the chain.

In simple terms, it's like installing a "trusted external hard drive" for smart contracts. Contracts don't need to store specific byte data but can verify that data blocks indeed exist, who paid for them, and what the current version is. This "contract-aware" storage is achieved through cryptographic commitments and on-chain pointers.

When uploading files, Walrus records an tamper-proof digital fingerprint on Sui. The smart contract then verifies this fingerprint to execute corresponding logic (renewal, access control, or triggering payments). The entire process remains lightweight. There's no need to upload massive data during execution, nor to trust a centralized server.

This approach opens up new possibilities: governance proposals can reference immutable evidence, DeFi applications can rely on certified datasets, and blockchain games can link assets to verifiable content. Developers' code becomes simpler, and guarantees for off-chain data become even stronger.

The core idea is "separation but accountability"—fast execution with deterministic results, scalable and persistent storage, cryptography-based interfaces, and contracts that can verify key data at any time. It's not magic; it's about using testable, elegant design to run real applications based on real data, without breaking the fundamental rules of blockchain.