Walrus's operation on Sui is quite interesting. The file metadata—such as owner, size, storage cycle—are not stored in an off-chain database, but are directly part of the Sui object state. What are the benefits of this? Anyone can verify at any time whether a file is genuinely stored and available, without relying on any centralized service for endorsement.

The upload process is as follows: you submit the file to Walrus, and the first step is to register the metadata information on-chain—this is the first on-chain record, and the network is already aware of your write request. Next, storage nodes divide the file into chunks and store them; after completion, they return a signature proof. Users compile these signatures into an availability certificate and submit it on-chain. This certificate generates a second on-chain event, which effectively announces: "This file is indeed accessible during the current cycle."

The roles of these two on-chain events go far beyond storage verification. They can also trigger internal smart contract logic. For example, a media file associated with an NFT can automatically extend its storage period based on specific conditions—this automated execution precisely depends on the triggering of these on-chain events.

More notably, the metadata is fully public on-chain, meaning other protocols can directly access this information. Cross-chain bridges, file indexing services, decentralized content delivery networks can all utilize it. Every storage operation in the Walrus network changes Sui's state tree, turning storage behavior itself into an on-chain economic activity.