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 0x673960a3b2ee11d976cfc735f4a57aafcee053af0fd7351ebc4d9fc917fc9aa9. Chain 2 (Bitcoin): anchored in block 953903 (2026-06-16T07:05:05Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/14f234f4-0adb-45bd-a092-362199dd7853.json and https://artists.proofprofile.net/proofs/artist/14f234f4-0adb-45bd-a092-362199dd7853.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.
Lunde, L.: Alto Saxophone Sonata No. 1 / Higgins, D.: Alto Saxophone Suite / Pierce, B.: 3 Street Scenes / Bruno, M.: Encore