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 0x389332b3da744c6cdc8ee6fd97f5ffa9452e6d8df5186cda95114a1a5701ce2b. Chain 2 (Bitcoin): anchored in block 953770 (2026-06-15T09:50:11Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/a60599d3-8be5-48ba-a63b-e228cf1db4c2.json and https://artists.proofprofile.net/proofs/artist/a60599d3-8be5-48ba-a63b-e228cf1db4c2.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.