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 0x690c3e37adf0a3e98c4ee1e0396e7b35a8e962361ead11f943df6c762de1a115. Chain 2 (Bitcoin): anchored in block 953750 (2026-06-15T06:12:23Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/ab1781ee-20a6-443c-bd09-237ad8cbca7c.json and https://artists.proofprofile.net/proofs/artist/ab1781ee-20a6-443c-bd09-237ad8cbca7c.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.