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 0x592ff1466090a7a1fd91be3d9b3e9014f8f9407ae004635ab30d866188ffe642. Chain 2 (Bitcoin): anchored in block 954631 (2026-06-21T02:46:24Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/cecd63a0-0056-47b7-a947-cd70f629c5e1.json and https://artists.proofprofile.net/proofs/artist/cecd63a0-0056-47b7-a947-cd70f629c5e1.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.
Voices from the Past, Vol. 1: Instruments of The Bate Collection, Oxford
Le Cor Mélodique: Mélodies, Vocalises & Chants by Gounod, Meifred & Gallay
Beyond Beethoven: Works for Natural Horn and Fortepiano