How Walrus submits Proof of Availability to Sui

Walrus submits its Proof of Availability PoA to Sui as a specialized onchain transaction via Move smart contracts, creating an immutable record that confirms data custody across the network. This process anchors the blob’s availability in Sui’s ledger, triggering storage obligations and enabling composable interactions. Upload Initiation. Users start by submitting an initial Sui transaction through a Publisher client, registering the blob’s metadata like its unique commitment a hash of the encoded data, size, and storage duration while paying fees in SUI or WAL upfront to a Storage Fund contract. The data gets encoded into slivers offchain, with commitments ensuring integrity, and distributed to a quorum of storage nodes typically two f plus one for fault tolerance in Byzantine settings. Nodes verify their assigned primary and secondary slivers against the commitments, recompute hashes to confirm validity, and sign cryptographic acknowledgments if correct. The client collects these signatures needing at least two f plus one to guarantee honest nodes hold reconstructible shares, forming the raw write certificate. PoA Transaction Submission. The client bundles this write certificate into a PoA transaction and broadcasts it to Walrus’s designated Move modules on Sui. Sui’s parallel execution processes it swiftly. The contract validates signatures, quorum threshold, and fee sufficiency, then mints or updates an onchain Blob object marking the PoA as the official point of availability. This object includes the blob ID, PoA details, deletion parameters for refunds, and links to proofs, all as first class Sui assets. Economic settlement happens atomically. Funds are allocated to staked WAL delegators and nodes for the paid epochs, with slashing risks applied for failures. Verification and Finality. Once onchain, the PoA serves as Sui’s canonical truth. Anyone can query the blob object for proofs, triggering reads via aggregators that reconstruct data from nodes. If challenged later, nodes prove ongoing custody, but the initial PoA upfront minimizes costs compared to constant proofs used by systems like Filecoin. Sui’s object model makes this programmable. dApps can reference the PoA directly in logic, such as gating NFT reveals until availability is confirmed. This tight integration keeps latency low with sub second finality and costs at pennies, avoiding the inefficiencies of sequential chains. $WAL {spot}(WALUSDT) @WalrusProtocol #Walrus