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 0x6b1373c2d05616ec9b012094f1a713964855847f959b74e1b269c2267a1a02fd. Chain 2 (Bitcoin): anchored in block 954615 (2026-06-20T22:44:50Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/c5b64e40-1e3a-4f8e-8f9b-f50ddf5ba9e6.json and https://artists.proofprofile.net/proofs/artist/c5b64e40-1e3a-4f8e-8f9b-f50ddf5ba9e6.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Another Someday Blues (Acoustic Duets from Chicago)