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 0x63fbc7367c2a09c07d2de4ada4a1f27f2478d1ac7f104daf2287f5331725e94e. Chain 2 (Bitcoin): anchored in block 953724 (2026-06-15T01:43:13Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/8f5dc7c5-311a-4ab9-a9b7-491e6df86956.json and https://artists.proofprofile.net/proofs/artist/8f5dc7c5-311a-4ab9-a9b7-491e6df86956.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.
Musica Sacra a S. Barbara all'epoca di Guglielmo Gonzaga - Gastoldi: Missa "Ne timeas Maria" & Quattro Antifone Mariane