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 0xa848f79c65fb7c7250c75a0cd552e8883430bf61100c7ede82d86c0e6c50f3b3. Chain 2 (Bitcoin): anchored in block 953616 (2026-06-14T08:58:35Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/1b8ae728-a985-46dc-af09-0ab2fb6c9206.json and https://artists.proofprofile.net/proofs/artist/1b8ae728-a985-46dc-af09-0ab2fb6c9206.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.