thumb|upright=0.8|In painting, Leonardo da Vinci's Mona Lisa ( 1503–06) is considered an archetypal masterpiece, although it was not produced for admission to a guild or academy. A masterpiece, , or
1. Compute SHA-256 of OTSCanonicalRecord value → must equal OTSHash 2. Open OTSProofURL → extract Bitcoin block number → must equal OTSBitcoinBlock 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Read CopyrightID inside OTSCanonicalRecord → must equal the CopyrightID above 5. GET OTSVerificationAPI → pre-computed 6-check result from server 6. If all match: this entity was registered on CopyrightChains at OTSTimestamp, independently verifiable on Bitcoin Note: an OTS proof may carry multiple Bitcoin attestations; OTSBitcoinBlock is the earliest confirmed one — a later attestation inside the proof corroborates it and is not a mismatch
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5f3c316129e03be288fa0dfe1b0b0cdfb4319ab498e38a2acb30e79dd591ee10. Chain 2 (Bitcoin): anchored in block 953610 (2026-06-14T07:58:09Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/141eb246-eb28-41f5-894f-a4d6329c322d.json and https://artists.proofprofile.net/proofs/artist/141eb246-eb28-41f5-894f-a4d6329c322d.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).