Register a local file fingerprint on Base Sepolia.
A polished transaction flow for timestamping a SHA-256 fingerprint without sending the file anywhere.
This MVP uses Base Sepolia testnet. No real funds are required.
Select file
Choose one or many files locally.
Generate fingerprint
Hash with Web Crypto.
Connect wallet
Use Base Sepolia.
Register proof
Write hash onchain.
Download receipt
Save JSON locally.
Create a proof
Network: Base Sepolia
Proof registration is disabled until your connected wallet is on Base Sepolia.
Select a file to begin.
Local JSON, no upload.
After registration, OpenProof generates a receipt with chain, contract, wallet, timestamp, BaseScan, and verification details.
Receipt appears after registration
Register a proof to see the downloadable receipt and BaseScan transaction link.
Recent Proofs
Stored only in this browser. Nothing is uploaded.
No local history yet
Proofs and verifications you complete in this browser will appear here.