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 0x8d71ca3cbc2a2818d29f47809ec499cec170fee2a7bd98c78223c4b412edc8af. Chain 2 (Bitcoin): anchored in block 954035 (2026-06-17T02:39:28Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/3c0a15c0-3f6d-4998-86f4-c0907839eb5d.json and https://artists.proofprofile.net/proofs/artist/3c0a15c0-3f6d-4998-86f4-c0907839eb5d.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.