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 0xfaaf9172ef9fc3396cf30acdcaaf0ba43d6f67b0d099583e125cf74c34d8b14d. Chain 2 (Bitcoin): anchored in block 953996 (2026-06-16T20:04:35Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/3009e480-20e9-4ae7-8445-49cf182eae8a.json and https://artists.proofprofile.net/proofs/artist/3009e480-20e9-4ae7-8445-49cf182eae8a.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.